Jeep+2.5TD+Motor+VM

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FUEL SYSTEM—2.5L DIESEL ENGINE TABLE TA BLE OF CONTENT S page

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FUEL DE FUEL DELIVE LIVERY RY SYST SYSTE EM— 2. 5L DIES DIESE EL ENG NGINE INE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

FUEL INJE FUEL INJEC CTION SYS SYSTE TEM— M— 2. 5L DIES DIESE EL ENG NGINE INE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3

FUEL DELIVERY SYSTEM—2.5L DIESEL ENGINE TABLE OF CONTENTS page

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DESCRIPTION AND OPERATION INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . 1 FUEL SYSTEM PRESSURE WARNING . . . . . . . . . 2 FUEL TANK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 FUEL FU EL TAN TANK K MODUL MODULE E ......................2 FUEL FU EL GAUGE GAUGE SEND SENDIN ING G UNIT UNIT . . . . . . . . . . . . . . . . 2 FUEL FILTER/WATER SEPARATOR . . . . . . . . . . . . 2 FUEL FUE L SHUTDOW SHUTDOWN N SOLENOID SOLENOID . . . . . . . . . . . . . . . 3 FUEL FU EL INJ INJEC ECTI TION ON PUMP PUMP . . . . . . . . . . . . . . . . . . . . 3 FUEL INJECTORS . . . . . . . . . . . . . . . . . . . . . . . . . 4 FUEL TUBES/LINES/HOSES AND CLAMPS— LOWLO W-PR PRES ESSUR SURE E TYPE TYPE . . . . . . . . . . . . . . . . . . . 4 QUICK-CONNECT FITTINGS—LOW PRESSURE TYPE. . . . . . . . . . . . . . . . . . . . . . . . 5 HIGH-PRESSURE FUEL LINES . . . . . . . . . . . . . . . 5 FUEL DRAIN TUBES . . . . . . . . . . . . . . . . . . . . . . . 6 FUEL HEATER. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 FUEL FU EL HEA HEATE TER R RELA RELAY . . . . . . . . . . . . . . . . . . . . . . 6 DIAGNOSIS DIAGNOS IS AND TESTING GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . 6 VISUAL INSPECTION. . . . . . . . . . . . . . . . . . . . . . . 6 AIR IN FUEL SYSTEM . . . . . . . . . . . . . . . . . . . . . . 9 FUEL HEATER RELAY TEST . . . . . . . . . . . . . . . . . 9 FUEL FU EL INJ INJEC ECTO TOR R TEST TEST . . . . . . . . . . . . . . . . . . . . 10 FUEL INJECTOR / NEEDLE MOVEMENT SENSOR TEST . . . . . . . . . . . . . . . . . . . . . . . . . 10

FUEL INJECTION PUMP TEST. . . . . . . . . . . . . . . 10 FUEL SUPPLY RESTRICTIONS . . . . . . . . . . . . . . 11 FUEL FUE L SHUTDOW SHUTDOWN N SOLENOID SOLENOID TEST . . . . . . . . . . 11 HIGH-PRESSU HIGHPRESSURE RE FUEL LINE LEAK TEST . . . . . . 11 SERVICE PROCEDURES AIR BLEED PROCEDURES . . . . . . . . . . . . . . . . . 12 FUEL INJECTION PUMP TIMING . . . . . . . . . . . . . 13 REMOVAL AND INSTALLATION ACCE AC CELE LERA RATO TOR R PEDAL PEDAL . . . . . . . . . . . . . . . . . . . . 13 FUEL DRAIN TUBES . . . . . . . . . . . . . . . . . . . . . . 14 FUEL FILTER/WATER SEPARATOR . . . . . . . . . . . 14 FUEL FU EL HEA HEATE TER R . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 FUEL HEATER RELAY . . . . . . . . . . . . . . . . . . . . . 15 FUEL LEVEL SENSOR. . . . . . . . . . . . . . . . . . . . . 15 FUEL FU EL INJ INJEC ECTI TION ON PUMP PUMP . . . . . . . . . . . . . . . . . . . 15 FUEL INJECTORS . . . . . . . . . . . . . . . . . . . . . . . . 19 FUEL TANK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 FUEL RESERVOIR MODULE . . . . . . . . . . . . . . . . 21 HIGH-PRESSURE LINES . . . . . . . . . . . . . . . . . . . 22 SPECIFICATIONS FUEL FU EL TAN TANK K CAPAC CAPACIT ITY Y . . . . . . . . . . . . . . . . . . . . 22 IDLE SPEED . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 FUEL INJECTOR FIRING SEQUENCE . . . . . . . . . 22 FUEL SYSTEM PRESSURE . . . . . . . . . . . . . . . . . 22

DESCRIPTION AND OPERATION

trolled by the PCM, refer to the Fuel Injection System—2.5L Diesel Engine section of this group. T h e fu e l h e a t e r r e la la y, y, fu e l h e a t e r a n d fu e l g a u g e are not operated by the PCM. These components are controlled by the ignition (key) switch. All other fuel system sys tem el elec ectric trical al compone mponents nts nec necessary essary to operate the engine are controlled or regulated by the PCM.

INTRODUCTION DESCRIPTION This Fu el Delivery Delivery sec section tion will will co cover ver co components mponents n ot ot con t r o ll ll ed ed b y t h e P C M. M. F or or com p o on n e n t s con -

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DESCRIPTION DESC RIPTION AND OPERATION OPERATION (Con (Continued) tinued)

FUEL SYSTEM PRESSURE WARNING

FUEL TANK MODULE

DESCRIPTION

DESCRIPTION

WARNING: HIGH–PR WARNING: HIGH–PRESSURE ESSURE FUEL LINES DELIVER DIESEL FUEL UNDER EXTREME PRESSURE FROM THE INJ INJECT ECTION ION PUMP TO THE FUE FUEL L INJE INJECTO CTORS. RS. THIS MAY BE AS HIGH AS 45,000 KPA (6526 PSI). USE EXT EXTREM REME E CAU CAUTION TION WHE WHEN N INSP INSPECT ECTING ING FOR HIGH HI GH–P –PRE RESS SSUR URE E FU FUEL EL LE LEAK AKS. S. IN INSP SPEC ECT T FO FOR R HIGH–PRESSURE FUEL LEAKS WITH A SHEET OF CARD CA RDBO BOAR ARD D (F (Fig ig.. 1) 1).. HI HIGH GH FU FUEL EL IN INJE JECT CTIO ION N PRES PR ESSU SURE RE CA CAN N CA CAUS USE E PE PERS RSON ONAL AL IN INJU JUR RY IF CONTACT IS MADE WITH THE SKIN.

An e le le ct ct r i c fu fu e l p u m p i s n o t a t t a c h ed ed t o t h e fu e l t a n k m od od u le le for d ie ie se se l p ow ow er er e d e n gi gin e s. s. F u e l i s drawn by the fuel injection pump. The fuel tank module is installed in the top of the fuel tank. The fuel tank module contains the following components: • Fuel reservoir Electric tric fuel gauge sendi sending ng unit • Elec • Fuel supply line connection line li ne connecti nnectio on • Fuel return • Wire harness • Fuel inlet filter (Strainer)

FUEL GAUGE SENDING UNIT DESCRIPTION The fuel gauge sending unit is attached to the side of the fuel pump module. The sending unit consists of a fl oa oa t , a n a r m , a n d a v a r ia ia b le le r e s is is t or or (t r a ck ck ). ). T h e track is used to send an electrical signal used for fuel gauge operation. As the fuel level increases, the float and arm move up. This decreases the sending unit resistance, causing the PCM to send a signal to the fuel gauge on the i n s tr t r u m en en t p a ne n e l t o r ea e a d fu ll l l. As t h e fu el el leve l d ec ecr ea e a se s e s, s, t h e floa t a n d a r m m ov ove d ow ow n . T hi his i n cr cr e a s es es t h e s en en d i n g u n i t r e s is is t a n ce c e , ca u s i n g t h e PCM to send a signal to the fuel gauge on the instrument panel to move toward empty.

FUEL FILTER/WATER SEPARATOR Fig. 1 Typical Fuel Pressure Test at Injection Pump 1 – FI FITT TTIN ING G 2 – HIGH PRESS PRESSURE URE LINE LINE 3 – CAR CARDBO DBOAR ARD D

FUEL TANK DESCRIPTION T h e fu fu e l t a n k a n d t a n k m ou ou n t in i n g u s e d w it it h t h e diesel powered engine is the same as used with gasoline powered models, although the fuel tank module is different. T h e f u el el t a n k con t a i n s t h e fu e l t a n k m od od u le le a n d one rol rollo lover ver val valve. ve. Two Two fuel lines lines are routed to t he fuel tank module. One line is used for fuel supply to t h e fu e l f il il t er er /w /w a t e r s ep ep a r a t or or . T h e ot h e r i s u s e d t o return excess fuel back to the fuel tank. The fuel tank module contains the fuel gauge electrical sending unit. A n e l e c t r i c f u e l p u m p i s n o t used with the diesel engine.

DESCRIPTION The fuel fil ilter/w ter/water ater separator assembl assembly y is lo loccated in the engine compartment near the strut tower (Fig. 2). T h e com b in in a t i on on fu e l fi lt lt e r /w /w a t e r s e pa pa r a t o r p r oot e ct ct s t h e fu e l i n je je ct ct i on on p u m p b y h e lp lp in in g t o r e m ov ov e water and contaminants from the fuel. Moisture collects at the bottom of the filter/separator in a plastic bowl. The fuel fil ilter/w ter/water ater separator assembl assembly y conta ins the fuel filter, fuel heater element, and water drain valve. F or or i n fo for m a t i on on on t h e fu e l h e a t e r , r e fe fe r t o F u e l Heater in this group. Refer to the maintenance schedules in Group 0 in this manual for the recommended fuel filter replacement intervals. For periodic draining of water from the bowl, refer to Fuel Fil Filter/W ter/Water ater Separator Remo Removal val//Installatio Installation n in this group.

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DESCRIPTION DESC RIPTION AND OPERATION OPERATION (Con (Continued) tinued)

Fig. 3 Fuel Injection Pump

Fig. 2 Fuel Filter/Water Separator Location

FUEL SHUTDOWN SOLENOID

1 2 3 4 5 6

– – – – – –

FUEL INJECTIO INJECTION N PUMP ASSEMB ASSEMBL LY FUEL RETU RETURN RN LINE LINE FUEL SUPP SUPPLY LY LINE FUEL INJECTION PUMP PUMP 10–WAY 10–WAY CONNECTOR CONNECTOR TIMING SOLE SOLENOID NOID OVERFLOW OVER FLOW VAL VALVE VE

DESCRIPTION The fuel shutdown solenoid is controlled and operated by the ECM. The fuel shutdown (shut-o shut-offf) soleno solenoid id is used to electrically shut off the diesel fuel supply to the highp r es es su su r e fu el e l in je je ct ct io ion p u mp m p . T he h e s ol ole no n oid is mounted to the rear of the injection pump. The solenoid controls starting and stopping of the engine engi ne regardle regardless ss of t he po positi sitio on of t he acc accel elerator erator p e da da l . W h en en t h e i gn gn i t io ion (k e y) y) s w it it ch ch i s O F F, F, t h e solenoid is shut off and fuel flow is not allowed to the fu e l i n je je ct ct i on on p u m p . W h e n t h e k e y i s p la la ce ce d i n t h e ON or START positions, fuel supply is allowed at the injection pump.

FUEL INJECTION PUMP DESCRIPTION The fuel injectio injection n pump is a mec mechan han ic ical al distri distribubutor–type, tor–ty pe, Bosch Bosch VP3 VP36 6 seri series es (Fig Fig.. 3) 3).. A gear on the e n d of t h e in je je ct ct io i on p u m p s h a ft ft m e sh sh e s w it it h t h e d r iv iv e g e a r a t t h e fr on on t of e ng n g in e. e . T he h e p u mp mp is m e ch ch a n i ca ca l ly ly t i m ed ed t o t h e e n gi gi n e. e. T h e E C M r e gu gu lates the timing of the injection pump. T h e i n je je ct ct i on on p u m p con t a i n s t h e fu e l s h u t d ow ow n solenoid, fuel temperature sensor, control sleeve sensor, fuel quantity actuator and the fuel timing solenoid (Fig. 3). In the electronically controlled injection pump, the pump plunger works the same as the pump plunger in a mec mechan han ic icall ally y contr oll lled ed inj injec ectio tion n pump, but the

a m ou ou n t of fu fu e l a n d t h e t i m e t h e fu e l i s i n je je ct ct e d i s con t r o ll ll ed ed b y t h e v eh eh i cl cl e’ e’s E C M, M, i n st st e a d of b y a mechanical go governor vernor assembly assembly.. A solenoid solenoid co cont nt rol rolled led by the ECM is used in place of the mechanical governor assembly, and it moves a control sleeve inside t h e p u m p t h a t r e gu gu la l a t e s t h e a m ou ou n t of f u el el b ei ei n g injected. There is no mechanical connection between the accelerator pedal and the electronically controlled i n je je ct ct i on on p u m p . I n s t ea ea d , a s e n so sor con n e ct ct e d t o t h e accelerator pedal sends a signal to the ECM that represents the actual positio position n of th e acc accel elerator erator pedal. T h e E C M u s es es t h is i s i np n p u t , a l on on g w it it h in p u t fr om om other senso sensors rs to mov movee the contr ol sle sleev evee to del deliv iver er the appropriate amount of fuel. This system is known as “Drive-By-Wire” T h e a c t u a l t i m e t h a t t h e fu e l i s d e l iv iv er er e d i s v er er y important to the diesel combustion process. The ECM monitors moni tors outputs from the engi engine ne spee speed d senso sensorr (fly ly-wheel position in degrees), and the fuel injector sens or or (m e ch ch a n i ca ca l m ov ov em em e n t w it it h i n t h e # 1 cy li li n de de r fuel inj injec ector) tor).. Outputs from the Accel elerator erator Pedal P os os it it i on on s e n so sor , e n gi gi n e s p ee ee d s e n so sor (e n gi gi n e r p m ) and engine coolant temperature sensor are also used. The ECM will then compare its set values to these outputs to electrically adjust the fuel timing (amount of a d va va n ce ce ) w it it h in in t h e i n je je ct ct io ion p u mp m p . T hi h is i s r e fe fe r r e d t o a s “C lo los e d L oo oop ” o p er er a t i on on . T h e E C M m on on i t or or s fu e l t i m i n g b y com p a r i n g i t s s e t v a lu lu e t o w h en en t h e i n je je ct ct or or # 1 o p en en s . I f t h e v a lu lu e i s g r e a t e r than a preset value a fault will be set.

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FUEL SYSTEM— 2.5L DIESEL ENGINE

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DESCRIPTION AND OPERATION (Continued) Actua l electric fuel timing (amount of advance) is accomplished by the fuel timing solenoid mounted to the bottom of the injection pump (Fig. 3). Fuel timing will be adjusted by the ECM, which controls the fuel timing solenoid. An overflow valve is attached into the fuel return l in e a t t h e r e a r of t h e fu e l i n je ct i on p u m p (F i g. 3 ). This valve serves two purposes. One is to ensure that a certain amount of residual pressure is maintained w it h i n t h e p u m p w h e n t h e e n gi n e i s s w it ch e d off. This will prevent the fuel timing mechanism within t h e i n je ct i on p u m p fr om r e t u r n i n g t o i t s z er o p os ition. The other purpose is to allow excess fuel to be r e t u r n ed t o t h e fu e l t a n k t h r ou gh t h e fu e l r e t u r n line. The pr essure values within t his valve ar e preset and can not be adjusted. T h e fu e l i n je ct i on p u m p s u p p li es h i gh – p r es s u r e fuel of a pproximately 45,000 kP a (6526 psi) t o each i n je ct or i n p r e ci se m e t e r ed a m ou n t s a t t h e cor r e ct time. F or m e ch a n i ca l i n je ct i on p u m p t i m in g , r e fe r t o F u e l I n je ct i on P u m p T im i n g i n t h e S e r vi ce P r o ce dures section of this group.

op en , it s en d s a s m a ll volt a ge s pik e p u ls e t o t h e ECM. This tells the ECM that the #1 cylinder injector is firing. It is not used with the other three injectors.

Fig. 5 Fuel Injector Sensor

FUEL INJECTORS DESCRIPTION The fuel injectors have controlled internal leakage which colls the injectors. Fuel drain tubes (Fig. 4) are used to route this fuel back to the overflow valve at t h e r e a r of t h e i n je ct i on p u m p . T h i s e xce s s f u e l i s t h en r et u r n ed t o t h e fu el t a n k t h r ou gh t h e fu el return line.

Fig. 4 Fuel Injectors and Drain Tubes The injectors are connected to the fuel injection p u m p b y t h e h i gh – p r e ss u r e fu e l l i n es . A s e pa r a t e i n je ct or i s u s e d for e a ch of t h e fou r cy li n de r s . A n i n je ct or con t a i n in g a s en s or (F i g. 5 ) i s u s e d on t h e nu mber one cylinder injector. Th is injector is called instrumented injector #1 or needle movement sensor. I t is u s ed t o t e l l t h e E C M w h e n t h e # 1 i n je ct or ’s i n t er n a l s p r in g -l oa d e d v a lv e s e a t h a s b ee n for ce d open by pressurized fuel being delivered to the cylind e r, w h ich i s a t t h e e n d of i t s com p r e ss ion s t r ok e . When the instrumented injector’s valve seat is force

1 2 3 4

– – – –

NEEDLE MOVEMENT SENSOR FUEL INJECTOR (NUMBER 1 CYLINDER ONLY) COPPER WASHER SENSOR CONNECTOR

F u e l e n t e r s t h e i n je ct or a t t h e fu e l i n l et (t op of injector) and is routed to the needle valve bore. When fuel pressure rises to approximately 15,000–15,800 kPa (2175–2291 psi), the needle valve spring tension is overcome. The needle valve rises a nd fuel flows t h r ou g h t h e s pr a y h ole s in t h e n ozzle t ip in t o t h e com b u s t ion ch a m b e r. T h e p r e ss u r e r e qu i r ed t o l ift the needle valve is the injector opening pressure setting. This is referred to as the “pop-off” pressure setting. Fuel pressure in the injector circuit decreases after injection. The injector needle valve is immediately closed by the needle valve spring and fuel flow into t h e com b u s t ion ch a m b e r i s s t op p ed . E x h a u s t g a se s a r e p r e ve n t e d fr om e n t e r in g t h e i n je ct or n oz zl e b y the needle valve. A cop pe r w a sh e r (ga s k et ) i s u s ed a t t h e b a se of each injector (Fig. 5) to prevent combustion gases from escaping. Fuel injector firing sequence is 1–3–4–2.

FUEL TUBES/LINES/HOSES AND CLAMPS— LOW-PRESSURE TYPE DESCRIPTION Also refer to the proceeding section on Quick–Connect Fittings.

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DESCRIPTION AND OPERATION (Continued) Inspect all h ose connections such as clamps, coup li n gs a n d fi t t in g s t o m a k e s u r e t h e y a r e s e cu r e a n d le a k s a r e n ot p r es en t . T h e com p on e n t s h ou ld b e replaced immediately if there is any evidence of degradation that could result in failure. Never attempt to repair a plastic fuel line/tube or a quick–conn ect fitting. Replace complete line/tube as necessary. Avoid contact of a ny fuel tubes/hoses with other v eh i cl e com p on e n t s t h a t cou l d ca u s e a b r a s ion s or scuffing. Be sure that the fuel lines/tubes a re prope r ly r ou t e d t o p r ev en t p in ch in g a n d t o a void h e a t sources. The lines/tubes/hoses are of a special construction. If it is necessary to replace t hese lines/tubes/hoses, use only original equipment type. T h e h os e c la m p s u s e d t o s ecu r e t h e r u b b er h os e s are of a special rolled edge constru ction. This cons t r u ct i on i s u s e d t o p r e v en t t h e e d ge of t h e cl a m p fr om cu t t i n g i n t o t h e h os e. O n ly t h e s e r ol le d e d ge t y pe cl a m p s m a y b e u s e d i n t h i s s y s t em . A ll ot h e r t yp es of c la m p s m a y cu t in t o t h e h os es a n d ca u s e fuel leaks. Wh er e a r u bb er h os e is join ed t o a m et a l t u be (s t a k e d), d o n ot a t t e m p t t o r e p a ir . R e p la ce e n t ir e line/tube assembly. U s e n e w or igi na l e qu ip m en t t yp e h os e cla m p s. Tighten hose clamps to 2 N·m (20 in. lbs.) torque.

QUICK-CONNECT FITTINGS— LOW PRESSURE TYPE DESCRIPTION Different types of quick-connect fittings are used to attach various fuel system components. These are: a single-tab type, a two-tab type or a plastic retainer ring type (Fig. 6). Refer to Quick-Connect Fittings in the Removal/Installation section for more information.

CAUTION: The interior components (o-rings, spacers) of quick-connect fitting are not serviced separately, but new pull tabs are available for some types. Do not attempt to repair damaged fittings or fuel lines/tubes. If repair is necessary, replace the complete fuel tube assembly.

HIGH-PRESSURE FUEL LINES DESCRIPTION CAUTION: The high–pressure fuel lines must be held securely in place in their holders. The lines cannot contact each other or other components. Do not attempt to weld high–pressure fuel lines or to

Fig. 6 Plastic Retainer Ring-Type Fitting 1 2 3 4 5 6 7 8

– – – – – – – –

FUEL TUBE QUICK CONNECT FITTING PUSH PLASTIC RETAINER PUSH PUSH PUSH PUSH

repair lines that are damaged. Only use the recommended lines when replacement of high–pressure fuel line is necessary. High–pressure fuel lines deliver fuel u nder press u r e of u p t o a p p r ox im a t e ly 4 5, 00 0 k P a (6 52 6 P S I ) fr om t h e i n je ct i on p u m p t o t h e fu e l i n je ct or s . T h e l in e s e xp a n d a n d con t r a c t fr om t h e h i gh – p r es s u r e fuel pulses generated during the injection process. All high–pressure fuel lines are of the same length and in s id e d ia m e t er . C or r e ct h ig h –p r es su r e fu e l lin e u s a g e a n d i n st a l la t i on i s cr i t ica l t o s m oot h e n gi n e operation.

WARNING: USE EXTREME CAUTION WHEN INSPECTING FOR HIGH–PRESSURE FUEL LEAKS. INSPECT FOR HIGH–PRESSURE FUEL LEAKS WITH A SHEET OF CARDBOARD. HIGH FUEL INJECTION PRESSURE CAN CAUSE PERSONAL INJURY IF CONTACT IS MADE WITH THE SKIN.

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DESCRIPTION AND OPERATION (Continued)

FUEL DRAIN TUBES DESCRIPTION T h es e r u b b er t u b e s a r e l ow –p r e ss u r e t y pe . S om e fuel is continually being returned to the fuel injection pump. During injection, a small amount of fuel flows p a s t t h e i n je ct or n e ed le a n d i s n o t i n je ct e d i n t o t h e combustion chamber. This cools and lubricates the injectors. This fuel flows through the fuel drain tubes (F i g. 7 ) a n d b a ck t o t h e t e e b a n jo f it t i n g, w h ich i s connected to the same line as the overflow valve. The overflow valve is calibrated to open at a preset pressure. Excess fuel not required by the pump to maint a in t h e m in im u m p u mp ca vit y p r es su r e is t h en r e t u r n e d t h r ou g h t h e ov er fl ow v a lv e a n d on t o t h e fu e l t a n k t h r o u gh t h e fu e l r e t u r n l in e .

Fig. 8 Fuel Heater Temperature Sensor and Element Location 1 – TERMINAL 2 2 – FUEL HEATER 3 – TERMINAL 1

FUEL HEATER RELAY Fig. 7 Fuel Drain Tubes

FUEL HEATER DESCRIPTION The fuel heater is used to prevent diesel fuel from w a xin g a n d p lu ggi n g t h e fu e l filt e r d u r in g cold weather operation. The fuel heater is located in the bottom plastic bowl of the fuel filter/water separator (Fig. 8). The element inside the heater assembly is made of a Positive Temperature Coefficient (PTC) material, and has power applied to it by the fuel heater relay anytime the ignition key is in the “on” position. PTC m a t e r i a l h a s a h i gh r e s is t a n ce t o c u r r e n t fl ow w h en its temperature is high, which means that it will not generate heat when the temperature is above a certain value. When the temperature is below 7°C (45° F), the resistance of the P TC element is lowered, and a l low s cu r r e n t t o f low t h r o u gh t h e fu e l h e a t e r e le m e n t w a r m in g t h e fu e l. Wh e n t h e t e m pe r a t u re is a b ov e 2 9°C (8 5° F ), t h e P T C e le m en t ’s r e s is t a n ce r i se s , a n d cu r r e n t fl ow t h r o u gh t h e h e a t e r e le m en t stops. Voltage to operate the fuel h eater is supplied from the ignition (key) switch and through the fuel heater relay. Refer to the following Fuel Heater Relay for additional informa tion. Th e fu e l h e a te r a n d fu e l h e a t e r r e la y a r e n o t c o n t r o ll e d b y t h e P o w e r train Control Module (PCM).

DESCRIPTION Voltage to operate the fuel h eater is supplied from t h e ign it ion (k e y) s wit ch t h r ou g h t h e fu e l h e a t er relay. T h e P C M o r E C M i s n o t u s e d t o c o n t r o l this relay. T h e f u e l h e a t e r r e la y i s l oca t e d i n t h e P D C . T h e PDC is located next to the battery in the engine comp a r t m en t . F or t h e l oca t ion of t h e r e la y w it h in t h e PDC, refer to label on PDC cover.

DIAGNOSIS AND TESTING GENERAL INFORMATION This section of the group will cover a general diagnosis of diesel engine fuel system components. D i a g n o s t i c Tr o u b le C o d e s : Refer to On-Board Diagnostics in Group 25, Em ission Control System for a list of Diagnostic Trouble Codes (DTC’s) for certain fuel system components.

VISUAL INSPECTION A visual inspection for loose, disconnected, or incorrectly routed wires and hoses should be made before a t t e m pt in g t o d ia gn os e or s er vice t h e d ie se l fu e l injection system. A visua l check will help find these conditions. It also saves unnecessary test and diagnostic time. A thorough visual inspection of the fuel injection system includes th e following checks:

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DIAGNOSIS AND T ESTING (Continued) (1) Be sure that the battery connections are tight and not corroded. (2 ) B e s u r e t h a t t h e 6 0 w a y con n e ct or is fu lly engaged with the PCM (Fig. 9). (3 ) B e s u r e t h a t t h e 6 8 w a y con n e ct or is fu lly engaged with the MSA (Fig. 10)

(4) Verify that the electrical connections for the ASD relay are clean and free of corrosion. This relay i s l oca t e d i n t h e P D C . F o r t h e l oca t i on of t h e r e la y within the PDC, refer to label on PDC cover. (5) Verify that the electrical connections for the fuel heater relay are clean and free of corrosion. This r e la y i s l oca t e d i n t h e P D C . F o r t h e l oca t i on of t h e relay within the PDC, refer to label on PDC cover. (6) Be sure the electrical connectors at the ends of the glow plugs (Fig. 11) are tight and free of corrosion.

Fig. 9 PCM Location—Typical 1 2 3 4

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PCM HARNESS CONNECTOR C1 PCM HARNESS CONNECTOR C2 PCM HARNESS CONNECTOR C3 POWERTRAIN CONTROL MODULE (PCM)

Fig. 10 ECM Location—LHD 1 2 3 4

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ECM HARNESS CONNECTOR C1 ENGINE CONTROL MODULE (ECM) ECM HARNESS CONNECTOR C2 ACCELERATOR PEDAL POSITION SENSOR

Fig. 11 Glow Plug Connector 1 – GLOW PLUG ELECTRICAL CONNECTOR

(7 ) B e s u r e t h a t t h e e le ct r i ca l con n e ct i on s a t t h e glow plug relay ar e tight and not corroded. The glow plug relay is located in the engine compart ment on the left–inner fender (Fig. 12). (8 ) I n s p e ct t h e s t a r t e r m ot or a n d s t a r t e r s ol en oi d connections for tightness and corrosion. (9) Verify that the Fuel Injection Pump electrical connector is firmly conn ected. Inspect th e connector for cor r os ion or d a m a g ed w ir e s . T h e s ol en oi d i s mounted to the rear of the injection pump (Fig. 13). (10) Verify th at the fuel heater electrical connector is firmly attached to the filter bowl at the bottom of the fuel filter/water separator. Inspect the connector for corrosion or damaged wires. (11) Verify tha t the electrical pigtail connector (sensor connector) (Fig. 14) for the fuel injector sensor is firmly connected to t he engine wiring h arness. Inspect the connector for corrosion or damaged wires. This sensor is used on the #1 cylinder injector only. (12) Inspect for exhau st system restrictions such as pinched exhau st pipes or a collapsed or plugged muffler. (1 3) Ve r ify t h a t t h e h a r n e s s con n e ct or i s fi r m ly connected to the vehicle speed sensor (Fig. 15).

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DIAGNOSIS AND T ESTING (Continued)

Fig. 12 Glow Plug Relay Location 1 – MOUNTING BOLT 2 – GLOW PLUG RELAY 3 – ELECTRICAL CONNECTOR

Fig. 13 Fuel Shutdown Solenoid Location 1 2 3 4 5 6

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FUEL INJECTION PUMP ASSEMBLY FUEL RETURN LINE FUEL SUPPLY LINE FUEL INJECTION PUMP 10–WAY CONNECTOR TIMING SOLENOID OVERFLOW VALVE

(1 4) Ve r ify t u r b och a r g e r w a s t eg a t e op e r a t ion . Refer to Group 11, Exhaust System and Intake Manifold Group for information. (1 5) Ve r ify t h a t t h e h a r n e s s con n e ct or i s fi r m ly connected to t he engine coolant temperatur e sensor.

Fig. 14 Fuel Injector Sensor 1 2 3 4

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Fig. 15 Vehicle Speed Sensor—4 Wheel Drive 1 – 4WD TRANSFER CASE EXTENSION 2 – VEHICLE SPEED SENSOR 3 – SENSOR ELECTRICAL CONNECTOR

T h e s e n sor i s l oca t e d on t h e s id e of c yl in d e r h e a d near the rear of fuel injection pump (Fig. 16). (16) Check for air in the fuel system. Refer to the Air Bleed Procedure. (1 7) I n s p e ct a l l f u e l s u p p l y a n d r e t u r n l in e s for signs of leakage.

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Fig. 16 Engine Coolant Temperature Sensor Location 1 2 3 4

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PCM ENGINE COOLANT TEMPERATURE (ECT) SENSOR ECM ENGINE COOLANT TEMPERATURE (ECT) SENSOR ECM ECT SENSOR HARNESS CONNECTOR PCM ECT SENSOR HARNESS CONNECTOR

(18) Be sure that the ground connections are tight and free of corrosion. Refer to Group 8, Wiring for locations of ground connections. (1 9) I n s pe ct t h e a i r cl ea n e r e le m en t (fi lt e r ) for restrictions. (20) Be sure that the turbocharger output hose is p r op e r ly con n e ct e d t o t h e ch a r g e a i r cool er (i n t er cooler) inlet tube. Verify that the charge air cooler output hose is pr operly connected to t he cooler and the intake manifold. Refer to Group 11, Exhaust System and Intake Manifold for information. (2 1) B e s u r e t h a t t h e v a cu u m h os e s t o t h e v a cu u m p u m p a r e con n e ct e d a n d n ot l ea k i n g. T h e v a cu u m pump is located in the front of engine (internal) and is driven from the crankshaft gear (Fig. 17). Disconnect the hose and check for minimum vacuum from the pump. Refer to Group 5, Brake System for specifications and procedures. (2 2) B e s u r e t h a t t h e a cce s sor y d r iv e b e lt i s n ot damaged or slipping. (23) Verify th ere is a good connection at th e engine speed sensor. Refer to t he Fuel Injection System in this section for location of t he engine speed sensor location. (24) Verify there is a good connection at the Boost P r e ss u r e S e n s or, w h ich is a p a r t of t h e a ir in t a k e assembly.

Fig. 17 Vaccum Pump at Front of Engine 1 2 3 4 5 6

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VACUUM PUMP CAMSHAFT INJECTION PUMP TIMING MARKS OIL PUMP CRANKSHAFT

AIR IN FUEL SYSTEM Ai r w il l e n t e r t h e fu e l s y s t em w h e n ev er t h e fu e l supply lines, fuel filter/water separator, fuel filter bowl, injection pump, high–pressure lines or injectors are removed or disconnected. Air will also enter the fu e l s ys t em w h en e ve r t h e fu e l t a n k h a s b ee n r u n empty. Air trapped in the fuel system can result in hard start ing, a rough runn ing engine, engine misfire, low power, excessive smoke an d fuel kn ock. After service i s p er for m e d, a ir m u s t b e b le d fr om t h e s ys t em before starting the engine. Inspect the fuel system from the fuel tank to the injectors for loose connections. Leaking fuel is an indicator of loose connections or defective seals. Air can also enter the fuel system between the fuel tank a n d t h e in je ct ion p u m p. I n sp ect t h e fu e l t a n k a n d fu e l l in e s for d a m a g e t h a t m i gh t a l low a i r i n t o t h e system. For air bleeding, r efer to Air Bleed P rocedure in the Service Procedures section of this group.

FUEL HEATER RELAY TEST The fuel heater relay is located in the Power Distr ibution Center (PDC). Refer to Relays—Operat ion/

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DIAGNOSIS AND T ESTING (Continued) Te s t in g i n F u e l I n ge ct i on S ys t e m s ect i on of t h i s group for test procedures.

FUEL INJECTOR TEST The fuel injection nozzels, located in the engine cy li n d er h e a d , s p r a y fu e l u n d e r h i gh p r e ss u r e i n t o t h e i n di vi du a l com b u s t ion ch a m b e r s. P r e s su r i ze d fuel, delivered by the fuel injection pump, unseats a spring-loaded needle valve inside the injector, and the fuel is atomized as it escapes through the injector opening into th e engine’s combust ion chamber. If th e fuel injector does not operate properly, the engine may misfire, or cause other driveability problems. A leak in the injection pump–to–injector high–pressure fuel line can cause many of the same symptoms as a malfunctioning injector. Inspect for a leak in the high–pressure lines before checking for a malfunctioning fuel injector.

WARNING: THE INJECTION PUMP SUPPLIES HIGH –PRESSURE FUEL OF UP TO APPROXIMATELY 45,000 KPA (6526 PSI) TO EACH INDIVIDUAL INJECTOR THROUGH THE HIGH–PRESSURE LINES. FUEL UNDER THIS AMOUNT OF PRESSURE CAN PENETRATE THE SKIN AND CAUSE PERSONAL INJURY. WEAR SAFETY GOGGLES AND ADEQUATE PROTECTIVE CLOTHING. AVOID CONTACT WITH FUEL SPRAY WHEN BLEEDING HIGH–PRESSURE FUEL LINES. WARNING: DO NOT BLEED AIR FROM THE FUEL SYSTEM OF A HOT ENGINE. DO NOT ALLOW FUEL TO SPRAY ONTO THE EXHAUST MANIFOLD WHEN BLEEDING AIR FROM THE FUEL SYSTEM. To determine which fuel injector is malfunctioning, run the engine a nd loosen th e high–pressure fuel line nut at the injector (Fig. 18). Listen for a change in engine speed. If engine speed drops, t he injector was op er a t in g n or m a ll y. I f e n gin e s pe ed r e m a in s t h e same, the injector may be malfunctioning. After testin g, t igh t en t h e lin e n u t t o 1 9 N ·m (1 4 ft . lb s.) torque. Test all injectors in the same manner one at a time. Once an injector has been found to be malfunctioni n g, r e m o ve i t f r om t h e e n gi n e a n d t e s t i t . R efe r t o th e Removal/Inst allation section of this group for procedures. After the injector has been removed, install it to a b en ch – m ou n t in je ct or t e st e r. R efe r t o op er a t in g instructions supplied with tester for procedures. The opening pressure or “pop” pressure should be 15,000–15,800 kPa (2175–2291 psi). If the fuel injector needle valve is opening (“popping”) to early or to late, replace the injector.

Fig. 18 Typical Inspection of Fuel Injector 1 2 3 4

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FUEL INJECTOR LINE FITTING HIGH-PRESSURE FUEL LINE FUEL DRAIN TUBES

FUEL INJECTOR / NEEDLE MOVEMENT SENSOR TEST T h e n e ed le m ov em e n t s e n sor i s u s e d on l y o n t h e num ber–1 cylinder fuel injector (Fig. 19). It is not used on the injectors for cylinders number 2, 3, or 4. Testing the needle m ovement sensor requires the u s e of a D RB S ca n t ool . R e fe r t o t h e P ow er t r a in Diagnostic Procedures man ual for additional information.

FUEL INJECTION PUMP TEST Th e i n je c ti on p u m p i s n o t t o b e s e rv ic e d o r t h e w a r ra n ty m a y b e v o id e d . I f t h e i n je c ti on p u m p r e qu i re s s e r v ic e , t h e c o m p le t e a s s e m bl y must be replaced. I n cor r e ct i n je ct i on p u m p t i m in g (m e ch a n i ca l or electrical) can cause poor performan ce, excessive smoke and emissions and poor fuel economy. A defective fuel injection pump, defective fuel timing solenoid or misadjusted mechanical pump timing ca n ca u s e s t a r t i n g p r o bl em s or p r e ve n t t h e e n gi n e from revving up. It can also cause: • Engine surge at idle • Rough idle (warm engine) • Low power • Excessive fuel consumption • Poor performance • Low power

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HIGH–PRESSURE LINES Restricted (kinked or bent) high–pressure lines can ca u s e s t a r t i n g p r ob le m s , p oor e n gi n e p e r for m a n c e and black smoke from exhaust. E x a m in e a l l h i g h –p r e ss u r e l in e s for a n y d a m a g e. E a ch r a d iu s on e a ch h ig h –p r es su r e lin e m u s t b e smooth and free of any bends or kinks. Replace dam aged, restricted or leaking high–pressure fuel lines with the correct replacement line.

CAUTION: The high–pressure fuel lines must be clamped securely in place in the holders. The lines cannot contact each other or other components. Do not attempt to weld high–pressure fuel lines or to repair lines that are damaged. Only use the recommended lines when replacement of high–pressure fuel line is necessary. Fig. 19 Needle Movement Sensor Location 1 2 3 4

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Black smoke from the exhaust • Blue or white fog like exhaust • Incorrect idle or maximum speed T h e e le ct r on i ca l ly con t r o ll ed fu e l p u m p h a s n o mechan ical governor like older mechanically controlled fuel pu mps. Do not remove the top cover of t h e fu e l p u m p , or t h e s cr e ws fa s t en in g t h e w ir in g p i g t a i l t o t h e s i d e o f t h e p u m p . T h e w a r ra n t y o f t h e i n je c t io n p u m p a n d t h e e n g i n e m a y b e v o i d if those seals have been removed or tampered with. •

FUEL SUPPLY RESTRICTIONS LOW–PRESSURE LINES Restricted or Plugged supply lines or fuel filter can cause a timing fault that will cause the ECM to opera t e t h e e ngin e in a “L im p H om e” m od e. S ee t h e i n t r od u ct i on of t h e F u e l I n je ct i on S ys t e m i n t h i s group for more information on the Limp Home mode. Fuel supply line restrictions can cause starting probl em s a n d p r e ve n t t h e e n gi n e f r om r e vv in g u p . T h e s t a r t i n g p r ob le m s i n cl u de ; l ow p ow er a n d b lu e or white fog like exhau st. Test all fuel supply lines for restrictions or blockage. F lush or replace as necessary. Bleed the fuel system of air once a fuel supply line has been replaced. Refer to the Air Bleed Procedure section of this group for procedures.

FUEL SHUTDOWN SOLENOID TEST Refer to 2000 XJ 2.5L Diesel Powertrain Diagnostic Manual for the Fuel Shutdown Solenoid test.

HIGH-PRESSURE FUEL LINE LEAK TEST H i gh – p r es s u r e fu e l l in e l ea k s ca n ca u s e s t a r t i n g problems and poor engine performance.

WARNING: DUE TO EXTREME FUEL PRESSURES OF UP TO 45,000 KPA (6526 PSI), USE EXTREME CAUTION WHEN INSPECTING FOR HIGH–PRESSURE FUEL LEAKS. DO NOT GET YOUR HAND, OR ANY PART OF YOUR BODY NEAR A SUSPECTED LEAK. INSPECT FOR HIGH–PRESSURE FUEL LEAKS WITH A SHEET OF CARDBOARD. HIGH FUEL INJECTION PRESSURE CAN CAUSE PERSONAL INJURY IF CONTACT IS MADE WITH THE SKIN. S t a r t t h e e n gin e . M ov e t h e ca r d boa r d ove r t h e high–pressure fuel lines and check for fuel spray onto the cardboard (Fig. 20). If a high–pressure line connection is leaking, bleed the system and tighten the connection. Refer to t he Air Bleed P rocedure in this group for procedures. Replace damaged, restricted or l ea k i n g h i gh – p r es s u r e fu e l l in e s w it h t h e cor r e ct replacement line.

CAUTION: The high–pressure fuel lines must be clamped securely in the holders. The lines cannot contact each other or other components. Do not attempt to weld high–pressure fuel lines or to repair lines that are damaged. Only use the recommended lines when replacement of high–pressure fuel line is necessary.

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DIAGNOSIS AND T ESTING (Continued) e ngin e s t ar t –u p or s ta r t –u p a ft er a n • I n it ia l extended period of no engine operation • Running fuel tank empty

FUEL INJECTION PUMP BLEEDING (1 ) I f t h e fu e l i n je ct i on p u m p h a s b ee n r e p la ce d , a i r s h ou ld b e b le d a t t h e ov er flow va lv e b efor e a t t e m p t in g t o s t a r t e n gi n e. (a ) L o os e n t h e ov er fl ow v a lv e (F i g. 2 1) a t t h e rear of the injection pump. (b) Place a towel below the valve.

Fig. 20 Typical Fuel Pressure Test at Injection Pump 1 – FITTING 2 – HIGH PRESSURE LINE 3 – CARDBOARD

SERVICE PROCEDURES AIR BLEED PROCEDURES AIR BLEEDING AT FUEL FILTER A certain amount of air may become trapped in the fu e l s ys t e m w h e n fu e l s ys t e m com p on e n t s a r e s e rviced or replaced. Bleed the system as needed after fuel system service according t o t he following procedures.

WARNING: DO NOT BLEED AIR FROM THE FUEL SYSTEM OF A HOT ENGINE. DO NOT ALLOW FUEL TO SPRAY ONTO THE EXHAUST MANIFOLD WHEN BLEEDING AIR FROM THE FUEL SYSTEM. Some air enters the fuel system when the fuel filt e r or i n je ct i on p u m p s u p p ly l in e i s ch a n g e d. T h is small amount of air is vented automatically from the injection pump through the fuel dra in m anifold tu bes if the filter was chan ged according t o instru ctions. E n s u r e t h e t h e fu e l f il t er /w a t e r s e pa r a t o r i s f u ll of fuel It may be necessary to manually bleed the system if: • The bowl of the fuel filter/water separator is not partially filled before installation of a new filter • The injection pump is replaced • High–pressure fuel line connections are loosened or lines replaced

Fig. 21 Overflow Valve 1 2 3 4 5 6

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WARNING: WHEN CRANKING THE ENGINE TO BLEED AIR FROM THE INJECTION PUMP, THE ENGINE MAY START. PLACE THE TRANSMISSION IN NEUTRAL OR PARK AND SET PARKING BRAKE BEFORE ENGAGING THE STARTER MOTOR. CAUTION: Do not engage the starter motor for more than 30 seconds at a time. Allow 2 minutes between cranking intervals. (2 ) C r a n k t h e e n gi n e for 3 0 s e con d s a t a t i m e t o a l low a i r t r a p p e d i n t h e i n je ct i on p u m p t o v e n t ou t the fuel injector dr ain tubes. Continue this procedure until the engine starts. Observe the previous WARNING and CAUTION. (3) Tight en overflow valve.

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SERVI CE PROCEDURES (Continued)

HIGH–PRESSURE FUEL LINE BLEEDING WARNING: THE INJECTION PUMP SUPPLIES HIGH –PRESSURE FUEL OF APPROXIMATELY 45,000 KPA (6,526 PSI) TO EACH INDIVIDUAL INJECTOR THROUGH THE HIGH–PRESSURE LINES. FUEL UNDER THIS AMOUNT OF PRESSURE CAN PENETRATE THE SKIN AND CAUSE PERSONAL INJURY. WEAR SAFETY GOGGLES AND ADEQUATE PROTECTIVE CLOTHING AND AVOID CONTACT WITH FUEL SPRAY WHEN BLEEDING HIGH–PRESSURE FUEL LINES.

FUEL INJECTION PUMP TIMING R efe r t o t h e F u e l I n je ct ion P u m p R em ov a l a n d Installation procedure in Service Procedures later in this Group.

REMOVAL AND INSTALLATION ACCELERATOR PEDAL REMOVAL

WARNING: DO NOT BLEED AIR FROM THE FUEL SYSTEM OF A HOT ENGINE. DO NOT ALLOW FUEL TO SPRAY ONTO THE EXHAUST MANIFOLD WHEN BLEEDING AIR FROM THE FUEL SYSTEM. Bleed air from one injector at time. (1 ) L oos e n t h e h i gh – p r es s u r e fu e l l in e fi t t in g a t the injector (Fig. 22).

Fig. 23 Accelerator Pedal Mounting-Typical 1 – PEDAL POSITION SENSOR

Fig. 22 Bleeding High–Pressure Fuel Line—Typical 1 2 3 4

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(2 ) C r a n k t h e e n gin e u n t il a ll a ir h a s b ee n b le d from t he line. D o n o t o p e r a t e t h e s t a r t e r m o t o r fo r lo n ge r t ha n 30 s e co n ds . Wa it 2 m in u te s between cranking intervals. (3 ) S t a r t t h e e n gi n e a n d b le ed on e i n je ct or a t a time until the engine runs smoothly.

(1) Disconn ect electrical connector. (2 ) Re m ov e a cce le r a t or p e da l m ou n t i n g b r a ck e t nuts. Remove accelerator pedal assembly.

INSTALLATION (1 ) P la ce a cce le r a t or p e da l a s s em b ly ov er s t u d s protruding from floor pan. Tighten mounting nuts to 5 N·m (46 in. lbs.) torque. (2) Conn ect electrical conn ector. (3) Before starting the engine, operate the accelerator pedal to check for any binding.

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REMOVAL AND INSTALLATION (Continued)

FUEL DRAIN TUBES T h e fu e l d r a i n t u b e s (F i g. 2 4) a r e l ow –p r e ss u r e type. Pull each tube from the injector for removal. Push on for installation. Clamps are not required for these tubes.

Fig. 24 Fuel Injectors and Drain Tubes

FUEL FILTER/WATER SEPARATOR T h e fu e l fi lt e r /w a t e r s e pa r a t o r i s l oca t e d i n t h e engine compartment on the left side near the shock tower. (Fig. 25).

initially placed in the ON position. This is done for a bulb check.

WARNING: DO NOT ATTEMPT TO DRAIN WATER FROM THE FILTER/SEPARATOR WITH THE ENGINE HOT. (1 ) T h e b ot t om of t h e filt e r /s ep a r a t or b ow l is e qu ip p ed w it h a d r a in v al ve (F ig. 2 5). T h e d r a in v a lv e i s e qu i pp e d w it h a fi t t in g . At t a c h a p ie ce of rubber hose to this fitting. This hose is to be used as a drain hose. (2) Place a drain pan under the drain hose. (3) Open the vent valve at top of fuel filter/water separator. (4 ) Wi t h t h e e n gi n e n o t r u n n i n g , op e n t h e d r a in v a lv e b y u n s cr e w in g t h e v a lv e (d r ai n v a lv e h a s r i g h t h a n d t h r e a d s ) from the filter/separator bowl. To g a in a cce ss t o t h is fit t in g , t h e t w o fi lt e r –t o– mounting bracket n uts (Fig. 25) may ha ve to be loosened a few turns. (5) Hold the drain open until clean fuel exits the drain. (6) After dra ining, close dr ain valve. (7) Remove rubber drain hose. (8 ) D i sp os e of m i xt u r e i n d r a i n p a n a ccor d in g t o applicable local or federal regulations.

FUEL FILTER REMOVAL (1) Drain all fuel and/or water from fuel filter/water separator assembly. Refer to the previous Draining Water From Filter Bowl. (2) Unplug the electrical connectors at bottom of plastic bowl. (3) Remove plastic bowl from bottom of fuel filter (unscrews). (4) Remove fuel filter from bottom of filter base (unscrews).

FUEL FILTER INSTALLATION

Fig. 25 Fuel Filter/Water Separator Location The fuel filter/water separator assembly conta ins t h e fu e l fi lt e r, fu e l h e a t e r e le m en t , a n d fu e l d r a i n valve (Fig. 25).

DRAINING WATER FROM FILTER BOWL Moisture (water) collects at the bottom of the filter/ separator in a plastic bowl. Water entering the fuel in je ct ion p u m p ca n ca u s e s er iou s d a m a ge t o t h e pump. Note that the bulb will be illuminated for a p pr ox im a te l y 2 s e c on d s e a c h t im e t h e k e y i s

(1) Clean bottom of fuel filter base. (2) Apply clean diesel fuel t o new fuel filter gasket. (3) Insta ll and t ight en filter to filter base. The beve le d p a r t of t h e r u b b er g a sk e t s h ou l d b e fa ci n g u p towards the filter base. (4) Clean the inside of bowl with a soap and water mixture before installation. Carefully clean any residue between the two metal probes at the top of the water–in–fuel sensor. Do not use chemical cleaners a s d a m a g e t o t h e p la s t i c bow l m a y r e s u lt . (5) Insta ll filter bowl t o bottom of filter. (6) Install t he electrical connectors at bottom of bowl. (7 ) Ti gh t e n t h e fi lt e r –t o– m ou n t i n g b r a ck e t n u t s (Fig. 25) to 28 N·m (250 in. lbs.) torque.

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FUEL HEATER

REMOVAL

I f t h e fu e l h e a t e r e le m en t n e ed s r e p la ce m en t , t h e plastic filter bowl assembly must be replaced. Refer to Fuel Filter/Water Separator for information.

(1) Remove fuel tan k. Refer t o Fuel Tank Removal/ Installation. (2) Remove fuel pum p module. Refer to Fu el Pum p Module Removal/Installation (3) Remove electrical wire connector at sending unit terminals. (4) Press on release tab (Fig. 28) to remove sending unit from pump module.

FUEL HEATER RELAY T h e f u e l h e a t e r r e la y i s l oca t e d i n t h e P D C . F o r t h e l oca t i on of t h e r e la y w it h i n t h e P D C (F i g. 2 6), refer to label on PDC cover.

Fig. 26 Power Distribution Center (PDC) Location

FUEL LEVEL SENSOR The fuel level sensor is located on the side of the fuel pump module. (Fig. 27)

Fig. 28 Fuel Level Sensor Release Tab 1 2 3 4

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ELECTRICAL CONNECTOR FUEL LEVEL SENSOR RELEASE TAB FUEL RESERVOIR MODULE

FUEL INJECTION PUMP REMOVAL

Fig. 27 Fuel Level Sensor 1 – FUEL GAUGE FLOAT 2 – FUEL GAUGE SENDING UNIT 3 – PIGTAIL WIRING HARNESS

(1) Disconnect th e negat ive bat tery cable. (2) Thoroughly clean the area around the injection pump and fuel lines of all dirt, grease and other contaminants. Du e to t he close inte rnal toler anc es o f t h e i n je c ti on p u m p , t h is s t ep m u s t b e p e rformed before removing pump. (3) Remove th e engine a ccessory drive belt. Refer to Group 7, Cooling System for procedures. (4) Remove th e genera tor a ssembly. (5) Re move t h e r u bb er fu el r et u r n a n d s u pp ly hoses from the metal lines at the pump (Fig. 29). (6) Remove the electrical connector at engine coolant temperature sensor. (7) Disconnect the Fuel Injection Pump electrical connector at fuel pump. (Fig. 29).

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REMOVAL AND INSTALLATION (Continued) cover for reference to TDC. Remove the alignment tool from the clutch housing. (12) Remove access plug and plug washer at rear of pum p (Fig. 30). Thread special dial indicator and a d a p t e r t ool VM .1 011 (F i g. 3 1) i n t o t h i s op e n in g . Hand tighten only.

Fig. 29 Fuel Injection Pump 1 2 3 4 5

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FUEL INJECTION PUMP ASSEMBLY FUEL RETURN LINE FUEL SUPPLY LINE FUEL INJECTION PUMP 10–WAY CONNECTOR FUEL TIMING SOLENOID

(8 ) Dis con n e ct t h e m a in e n gin e w ir in g h a r n e ss from the glow plugs. (9) Disconnect the four high–pressure fuel lines from the fuel injection pump. Also disconnect fuel l in e s a t t h e fu e l i n je ct or s . F or p r oce d u r es , r e fe r t o High–Pressure Fuel Lines in this group. Place a rag beneath the fittings to catch excess fuel. (10) Remove the plug from timing gear cover. (11) The “Top Dead Center” (TDC) compression firing stroke for the #1 cylinder can be determined as follows: (a ) U s i n g a s ock e t a t t a c h ed t o t h e fr on t of t h e crankshaft, rotate the engine clockwise until speci al a lign m e n t t ool VM # 1 04 3 ca n b e in s er t e d through the hole in the bottom of the clutch housing, stopping the flywheel rotation. This position is TDC or 180° away from TDC. E n g in e m u s t b e a t T D C # 1 c o m p r e s s i o n f ir i n g s t r o k e . (b) To verify t hat you are at #1 TDC Compression. Remove the oil fill cap from the cylinder head cover and the alignment tool from the clutch housing. (c) R ot a t e t h e cr a n k s h a f t on e -q u a r t e r t u r n cl ock wise and counter-clockwise while observing the rocker a r m t h r ou g h t h e oi l fi ll ca p h ol e. I f t h e r ock e r a r m moves you are not at #1 TDC Compression. (d) If #1 TDC Compression was found continue, if not rotate t he cran kshaft one revolution until th e alignment tool can be r e-installed in the flywheel. You are now at TDC for the #1 cylinder compress ion fi rin g s t r ok e . M a r k t h e d a m pe r a n d t im in g

Fig. 30 Access Plug at Rear of Pump 1 – ACCESS PLUG 2 – WASHER

Fig. 31 Installing Dial Indicator and Special Adapter Tools 1 – DIAL INDICATOR TOOL 2 – ADAPTER TOOL VM1011

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REMOVAL AND INSTALLATION (Continued) (13) Slightly rotate the engine in a count er-clockw is e d ir e ct i on u n t i l t h e d ia l g a u ge i n di ca t or s t op s moving (20°-25° before TDC). (14) Remove injection pump drive gear nut (Fig. 32).

(a) Thread the adapter (Fig. 34) into the timing cover. (b ) T h r ea d t h e ge a r p u lle r i n to t h e in je ct ion pump drive gear (Fig. 34). This tool is also used to h old t h e g ea r in s yn ch r on iza t ion d u r in g p u m p removal. (c) R em ov e t h e t h r e e i n je ct i on p u m p – t o– ge a r cover mounting nut s (Fig. 35). CAUTION: This step must be done to prevent injection pump damage. (d ) I n st a ll t h e d r ive b olt in t o t h e ge a r p u ll er (Fig. 34). Tighten the drive bolt to press (remove) t h e d r iv e g e a r fr om i n je ct i on p u m p s h a ft w h il e driving injection pump rearward from timing gear cover mounting studs.

Fig. 32 Removing Pump Drive Gear Nut 1 – TIMING GEAR COVER 2 – INJECTION PUMP GEAR 3 – PUMP GEAR NUT

(1 5) A s pe cia l 3 –p ie ce g ea r r e mov a l t ool s et VM.1003 (Fig. 33) must be used to remove the injection pump drive gear from the pump shaft.

Fig. 34 Installing Pump Drive Gear Removal Tools 1 – ADAPTER 2 – DRIVE BOLT 3 – GEAR PULLER

(16) Remove pump from engine. D o n o t r ot at e e n g in e w h i le g e a r p u ll e r i s i n st al le d . E n gi n e damage will occur.

INSTALLATION/ADJUSTING PUMP TIMING Fig. 33 Pump Gear Tools 1 – DRIVE BOLT 2 – TIMING COVER ADAPTER 3 – GEAR PULLER

(1 ) C le a n t h e m a t i n g s u r fa ce s of i n je ct i on p u m p and timing gear cover. (2 ) I n s t a ll a n e w i n je ct i on p u m p –t o– t im i n g g ea r cover gasket. (3 ) Re m ov e t h e g ea r r e m ov in g b ol t (d r iv e b ol t ) from gear puller. C AU T IO N : D o n o t r e m o v e t h e s pe c ia l g e ar p u lle r o r t im in g c ov e r a da pt er tools from timing cover at this time. Gear misalignment will result.

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Fig. 35 Injection Pump Mounting Nuts 1 – MOUNTING FLANGE 2 – SLOTTED HOLES (3) 3 – PUMP MOUNTING NUTS (3)

Fig. 36 Access Plug at Rear of Pump (4 ) P l a ce t h e k e y w a y on t h e p u m p s h a ft t o t h e 1 1 o’clock position as viewed from the front of pump. I n s t a ll t h e p u m p i n t o t h e r e a r of t i m in g g ea r cov er w h il e a l ign in g k ey w a y o n p u m p s h a ft in t o p u m p gear. (5) Install and snug the 3 injection pump mounting nuts. This is not the final tightening sequence. (6 ) Re m ov e t h e s p eci a l g e a r p u ll er a n d a d a p t e r tools from timing gear cover. (7 ) I n st a ll t h e in je ct ion p u mp d r ive gea r n u t . Tighten nut to 88 N·m (65 ft. lbs.) torque. (8 ) R em ov e t h e a cce ss p lu g a n d p lu g w a sh e r a t rear of pump (Fig. 36). Thread special dial indicator a d a p t e r t ool VM .1 011 (F i g. 3 7) i n t o t h i s op e n in g . Hand tighten only. (9) Attach special dial indicator tool VM.1013 into the adapter tool (Fig. 37) (1 0) U s in g a s ock et a t t a ch e d t o t h e fr on t of t h e crank shaft, r otat e the engine in a count er-clockwise direction unt il the dial gage indicator stops moving (20–25° before TDC). (11) Set the dial indicator to 0mm. Be sure the tip of t h e d ia l i n d ica t or i s t ou ch i n g t h e t i p i n si de t h e adapter tool. (1 2) Rot a t e t h e e n gin e clock w is e u n t il s pe cia l alignment tool VM# 1043 can be inserted through the hole in the bottom of the clutch housing, stopping the flywheel rotation. This position is #1Cylinder TDC Compression. E n gi ne m u st b e a t T D C # 1 c o m p r e s s i o n f i r in g s t r o k e . (1 3) Th e ga u ge r ea d in g s h ou ld b e a t 0 .5 5 m m ( w i th n e w g e a rs i n s ta l le d s p e c if ic a t io n s h o u ld be 0.59–0.60mm) . I f n o t , t h e p u m p m u s t b e r o t a t e d for adjustment:

1 – ACCESS PLUG 2 – WASHER

Fig. 37 Installing Dial Indicator and Special Adapter Tools 1 – DIAL INDICATOR TOOL 2 – ADAPTER TOOL VM1011

(a ) L oos e n t h e t h r e e i n je ct i on p u m p m ou n t i n g n u t s a t t h e m ou n t in g fla n g es . T h es e fl a ng es a r e equipped with slotted holes. The slotted holes are used to rotate and position the injection pump for fu e l t i m in g . L oos en t h e t h r e e n u t s ju s t e n ou g h t o rotate the pump.

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REMOVAL AND INSTALLATION (Continued) (b) Rotate the pump until 0.55 mm is indicated on t h e d ia l i n di ca t or g a u ge . I f w h il e r o t a t i n g t h e pump the 0.55 mm specification is passed do not a t t e m p t t o r o t a t e t h e p u m p i n t h e op p os it e d ir e ct ion . You m u s t r ot a t e t h e p u m p b a ck b elow t h e 0.25 mm specification and start the procedure over from th e st art of the TDC procedure. This will prevent a false reading due to gear backlash. (c) T ig h t en t h e t h r e e p u m p m ou n t i n g n u t s t o 3 0 N·m (22 ft. lbs.) torque. (d ) R e ch e ck t h e d ia l i n d ica t or a ft e r t i gh t e n in g t h e p u m p m ou n t in g n u t s . G a u ge s h ou ld s t ill b e reading 0.55 mm. (14) Remove dial indicator and adapter tools. (1 5) I ns t all a cce ss p lu g a n d w as h er t o r ea r of injection pump. (16) Install plug at timing gear cover. (1 7) I n s t a ll a n d con n e ct t h e fou r h i gh – p r es s u r e fuel lines to the fuel injection pump. Also connect fuel lines at the fuel injectors. For procedures, r efer to High–Pressure Fuel Lines in this group. (18) Inst all electrical connector at engine coolant temperature sensor. (19) Connect electrical connector at fuel shutdown solenoid. (2 0) C on n e ct t h e m a i n e n gi n e w i r in g h a r n e s s t o the glow plugs. (21) Connect the fuel timing solenoid pigtail harn e s s t o t h e e n gi n e w ir i n g h a r n e ss . (22) Conn ect th e overflow valve/banjo fitting (fuel return line assembly). Replace copper gaskets before installing. (2 3) C on n e ct t h e r u b be r fu e l r e t u r n a n d s u pp ly hoses to metal lines at pump. Tighten hose clamps to 2 N·m (20 in. lbs.) torque. (24) Install generator assembly. (25) Install engine accessory drive belt. Refer to Group 7, Cooling System for procedures. (26) Install negative battery cable to battery. (27) Start the engine and bring to normal operati n g t e m p er a t u r e . (28) Check for fuel leaks.

Fig. 38 Fuel Injector Sensor — #1 Cylinder 1 2 3 4

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(2) Thoroughly clean the area around the injector with compressed air. (3 ) R em ov e t h e fu e l d r a i n h os e s (t u b e s) a t e a ch injector (Fig. 39) being serviced. Each of these hoses is slip–fit to the fitting on injector.

FUEL INJECTORS F ou r fu e l i n j ect or s a r e u s e d on e a ch e n gi n e. O f t h e s e fou r , t w o d i ffe r e n t t y pe s a r e u s e d. T h e fu e l i n je ct or u s e d on cy li n d er n u m b e r on e i s e qu i pp e d with a fuel injector sensor (Fig. 38). The other three fuel injectors are identical. D o n o t p l a c e t h e f u e l injector equipped with the fuel injector sensor i nt o a n y o th e r lo ca ti on e x ce p t t he c yli nd e r n u m b e r o n e p o s it i on .

REMOVAL (1) Disconnect negative battery cable at battery.

Fig. 39 Fuel Injector—Typical 1 2 3 4

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REMOVAL AND INSTALLATION (Continued) (4) Remove th e high–pressure fuel line at injector being removed. Refer to High–Pressure Fuel Lines in this group for procedures. (5) Remove the injector using special socket tool number VM.1012A. When removing cylinder number one injector, thread the wiring harness through the access hole on th e special socket (Fig. 40).

Fig. 40 Wiring Harness Through Socket 1 2 3 4

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FUEL INJECTOR WIRING HARNESS (NUMBER 1 CYLINDER ONLY) SPECIAL SOCKET FUEL INJECTOR SENSOR (NUMBER 1 CYLINDER ONLY)

Fig. 41 Fuel Tank Connections at Front of Tank 1 2 3 4

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FUEL SUPPLY LINE CONNECTION FUEL PUMP MODULE CONNECTOR FRONT OF FUEL TANK EVAP CANISTER VENT LINE CONNECTION

1 2 3 4 5 6 7 8

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FUEL TANK CLAMP INDEX MARKS TANK INDEX TANGS HOSE INDEX MARKS FUEL FILL HOSE CLAMP INDEX MARKS CLAMPS FUEL VENT HOSE

(6) Remove and discard the copper washer (seal) at bottom of injector (Fig. 38).

INSTALLATION (1) Clean the injector threads in cylinder head. (2) Install new copper washer (seal) to injector. (3 ) I n s t a l l i n je ct or t o e n gi n e. T ig h t en t o 7 0 N · m (52 ft. lbs.) torque. (4) Install high–pressure fuel lines. Refer to High– Pressure Fuel Lines in this group for procedures. (5) Install fuel drain hoses (tubes) to each injector. Do not use clamps at fuel drain hoses. (6) Connect negative battery cable to battery. (7) Bleed the air from the high–pressure lines. Refer to the Air Bleed Procedure section of this group.

FUEL TANK REMOVAL (1) Disconn ect negative cable from ba tter y. (2) Insert fuel siphon hose into fuel filler neck and push it into the tank. (3 ) Dr a in fu el t a n k d ry in t o h old in g t a n k or a properly labeled d i e s e l safety container. (4) Raise vehicle on hoist. (5) Disconnect both the fuel fill and fuel vent rubber hoses at the fuel tank. (6) Disconnect fuel su pply and return lines from the steel supply line (Fig. 41). T h e fu e l r e s e rv o i r m o d u l e e l e c tr ic a l c o n n e c t o r h a s a r e ta i n e r t h a t l o c k s i t i n p l ac e . (7) Slide electrical connector lock to un lock.

Fig. 42 Fuel Fill/Vent Hose Index Marks

(8) Push down on connector retainer (Fig. 43) and pull connector off module.

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FUEL RESERVOIR MODULE REMOVAL WARNING: THE FUEL RESERVOIR OF THE FUEL MODULE DOES NOT EMPTY OUT WHEN THE TANK IS DRAINED. THE FUEL IN THE RESERVOIR WILL SPILL OUT WHEN THE MODULE IS REMOVED.

Fig. 43 Module Connector Retainer and Lock 1 – PUSH DOWN ON RETAINER 2 – CONNECTOR LOCK

(9 ) U s e a t r a n s m i ss ion ja ck t o s u p p or t fu e l t a n k . Remove bolts from fuel tank straps. (10) Lower tank slightly. Carefully remove filler hose from tank. (11 ) L ow er t h e fu el t a n k. R em ove cla m p a n d remove fuel filler tube vent hose. Remove fuel t ank from vehicle.

(1) Disconnect negative cable from ba tter y. (2) D r ain fu el t a n k d r y in t o h old in g t a n k or a properly labeled d i e s e l safety container. (3) Raise vehicle on h oist. (4 ) U se a t r a n s m is sion ja ck t o s u pp or t t h e fu e l t a n k . R em ov e b olt s fr om fu e l t a n k s t r a ps . L ow er tank slightly. (5 ) C le a n a r e a a r o u n d fu e l r e s er v oi r m od u le a n d t a n k t o k e e p d i r t a n d for e ig n m a t e r ia l o u t of t a n k . (6 ) D is con n e ct fu e l l in e s fr om fu e l m od u le b y d ep r e ss in g q u ick con n e ct r e t a in e r s w it h t h u m b a n d fore finger. (7 ) S lid e m od u le e le ct r ica l con n e ct or lock t o unlock. (8) Push down on connector retainer and pull connector off module. (9) Usin g Special Tool 6856, rem ove plast ic lockn ut counterclockwise to release pump module (Fig. 44).

INSTALLATION (1) Position fuel t ank on tra nsmission jack. Connect fuel filler tube vent hose and replace clamp. (2 ) Ra i se t a n k i n t o p os it i on a n d ca r e fu l ly w or k filler tube into ta nk. A light coating of clean engine oil on the tube end may be used to aid assembly. (3) Feed filler vent line thorough frame rail. Careful not to cross lines. (4 ) T igh t e n s t r a p b olt s t o 9 N ·m (8 0 i n . lb s.). Remove transmission jack.

CAUTION: Ensure straps are not twisted or bent before or after tightening strap nuts. (5 ) C on n e ct m od u le e le ct r i ca l con n e ct or . P l a ce retainer in locked position. (6) Lubricate the fuel supply and return lines with clean 30 weight engine oil, install the quick connect fuel fitting. Refer to Tube/Fitting Assembly in the Fuel Delivery section of this Group. (7) Attach filler line to filler tube. Pull on connector to make sure of connection. (8) Fill fuel tank, replace cap, and connect battery negative cable.

Fig. 44 Fuel Reservoir Module Lock Nut Removal 1 – SPECIAL TOOL 6856 2 – LOCKNUT

(10) Carefully r emove module an d o-ring from tank. (11) Discard old o-ring.

INSTALLATION (1) Thoroughly clean locknut threads and mating fule tan k threads. U se a soap/water solution. D o N o t use carburetor cleaner to clean threads. (2) Apply clean water to the o-ring seal and place on the mating fuel tank threads.

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REMOVAL AND INSTALLATION (Continued) (3) Wipe seal area of tan k clean a nd place a new o-ring seal in position on pump. (4) Position fuel reservoir module in tank with locknut. (5) Tighten locknut to 75 N·m (55 ft. lbs.). (6) Conn ect fuel lines. (7) Plug in electrical connector. Slide connector lock into position. (8 ) Ra is e fu e l t a n k , in s t a ll b ol ts in t o fu e l t a n k straps and tighten. (9) Lower vehicle on hoist. (10) Connect negative cable from battery. (11) Fill fuel tank. Check for leaks. (12) Inst all fuel filler cap.

HIGH-PRESSURE LINES All high–pressure fuel lines are of the same length and inside diameter. Correct high–pressure fuel line usage and installation is critical to smooth engine operation.

CAUTION: The high–pressure fuel lines must be clamped securely in place in the holders. The lines cannot contact each other or other components. Do not attempt to weld high–pressure fuel lines or to repair lines that are damaged. Only use the recommended lines when replacement of high–pressure fuel line is necessary.

REMOVAL (1) Disconnect negative battery cable from battery. (2) Remove the necessary clamps holding the lines to the engine. (3 ) C l ea n t h e a r e a a r ou n d e a ch fu e l l i n e c on n e ct i on . D is con n e ct e a ch l in e a t t h e t op of e a c h fu e l injector (Fig. 45). (4) Disconnect each high–pressure line fitting at each fuel injection pump delivery valve. (5) Very carefully r emove each line from the engine. Note t he position (firing order) of each line while r emoving. D o n o t b e n d t h e l in e w h i l e r e m o v i ng .

CAUTION: Be sure that the high–pressure fuel lines are installed in the same order that they were removed. Prevent the injection pump delivery valve holders from turning when removing or installing high–pressure lines from injection pump.

INSTALLATION (1) Carefully position each h igh–pressure fuel line to the fuel injector and fuel injection pump delivery valve holder in the correct firing order. Also position each line in the correct line holder. (2) Loosely insta ll th e line clamp/holder bolts. (3 ) T ig h t en e a ch l in e a t t h e d e li ve r y v a l ve t o 1 9 N·m (168 in. lbs.) torque.

Fig. 45 Fuel Lines at Fuel Injectors 1 2 3 4

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(4) Tighten each line at the fuel injector to 19 N·m (168 in. lbs.) torque. B e s u re t he li ne s a re n o t c on ta ct in g e a ch o t h e r o r a n y o t h e r c o m p o n e n t. (5) Bleed a ir from th e fuel system. Refer t o the Air Bleed Procedure section of this group.

SPECIFICATIONS FUEL TANK CAPACITY 75 Liters (20.0 Gals.) Nominal refill capacities are shown. A variation may be observed from vehicle to vehicle due to manu fa ct u r in g t ole r a n ce s, a m b ie n t t e m pe r a t u r es a n d refill procedures.

IDLE SPEED 7 5 0 R P M 2 5 R P M with engine at normal opera t i n g t e m p er a t u r e .

FUEL INJECTOR FIRING SEQUENCE 1–3–4–2

FUEL SYSTEM PRESSURE Peak Injection Pressure/Fuel Injection Pump O pe r a ti n g P r e s s u re : 40,000–45,000 kPa (5801– 6526 psi). Op e ni ng P re ss ur e o f F u el In je c to r: 16,500– 17,300 kPa (2393–2509 psi).

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FUEL INJECTION SYSTEM—2.5L DIESEL ENGINE TABLE OF CONTENTS page

page

DESCRIPTION AND OPERATION FUEL INJECTION SYSTEM . . . . . . . . . . . . . . . . . 23 POWERTRAIN CONTROL MODULE (PCM) . . . . . 24 BOOST PRESSURE SENSOR . . . . . . . . . . . . . . . 25 VEHICLE THEFT ALARM . . . . . . . . . . . . . . . . . . . 25 BATTERY VOLTAGE—PCM INPUT. . . . . . . . . . . . 25 SENSOR RETURN—ECM/PCM INPUT (ANALOG GROUND). . . . . . . . . . . . . . . . . . . . . 26 IGNITION CIRCUIT SENSE—ECM/PCM INPUT . . 26 IGNITION CIRCUIT SENSE—PCM INPUT . . . . . . 26 POWER GROUND . . . . . . . . . . . . . . . . . . . . . . . . 26 NEEDLE MOVEMENT OR INTRUMENTED FIRST INJECTOR—ECM INPUT . . . . . . . . . . . . 26 FUEL INJECTOR SENSOR—GROUND. . . . . . . . . 26 ENGINE COOLANT TEMPERATURE SENSOR—ECM/PCM INPUT. . . . . . . . . . . . . . . 26 ENGINE SPEED SENSOR—ECM INPUT . . . . . . . 26 AIR CONDITIONING (A/C) CONTROLS—ECM INPUTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 BRAKE SWITCH—ECM INPUT. . . . . . . . . . . . . . . 28 DATA LINK CONNECTOR—PCM AND ECM INPUT AND OUTPUT . . . . . . . . . . . . . . . . . . . . 28 VEHICLE SPEED SENSOR—ECM INPUT . . . . . . 28 SPEED CONTROL—ECM INPUT . . . . . . . . . . . . . 28 ASD RELAY—ECM INPUT . . . . . . . . . . . . . . . . . . 29 FIVE VOLT POWER—ECM/PCM OUTPUT . . . . . . 29 ENGINE COOLANT GAUGE—PCM OUTPUT . . . . 29 ENGINE OIL PRESSURE GAUGE—PCM OUTPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 GLOW PLUG LAMP—PCM OUTPUT . . . . . . . . . . 29 SPEED CONTROL—PCM OUTPUTS . . . . . . . . . . 29

AIR CONDITIONING RELAY—ECM OUTPUT . . . . 29 TIMING SOLENOID—ECM OUTPUT . . . . . . . . . . 29 TACHOMETER—PCM OUTPUT . . . . . . . . . . . . . . 30 GLOW PLUG RELAY—ECM OUTPUT . . . . . . . . . 30 GLOW PLUGS . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 ELECTRIC VACUUM MODULATOR (EVM)— ECM OUTPUT. . . . . . . . . . . . . . . . . . . . . . . . . . 31 DIAGNOSIS AND TESTING DIESEL DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . 31 ASD RELAY TEST . . . . . . . . . . . . . . . . . . . . . . . . 31 ENGINE SPEED SENSOR TEST . . . . . . . . . . . . . 31 ENGINE COOLANT TEMPERATURE SENSOR TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 GLOW PLUG TEST . . . . . . . . . . . . . . . . . . . . . . . 31 GLOW PLUG RELAY TEST . . . . . . . . . . . . . . . . . 33 RELAYS—OPERATION/TESTING. . . . . . . . . . . . . 34 BOOST / PRESSURE SENSOR . . . . . . . . . . . . . . 34 VEHICLE SPEED SENSOR TEST. . . . . . . . . . . . . 35 DIAGNOSTIC TROUBLE CODES . . . . . . . . . . . . . 35 REMOVAL AND INSTALLATION ASD RELAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 A/C CLUTCH RELAY . . . . . . . . . . . . . . . . . . . . . . 35 ENGINE SPEED SENSOR . . . . . . . . . . . . . . . . . . 35 ENGINE COOLANT TEMPERATURE SENSOR. . . 35 GLOW PLUGS . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 GLOW PLUG RELAY . . . . . . . . . . . . . . . . . . . . . . 36 POWERTRAIN CONTROL MODULE (PCM) . . . . . 36 VEHICLE SPEED SENSOR . . . . . . . . . . . . . . . . . 37 SPECIFICATIONS GLOW PLUG CURRENT DRAW. . . . . . . . . . . . . . 38 TORQUE CHART—2.5L DIESEL. . . . . . . . . . . . . . 38

DESCRIPTION AND OPERATION

Certain fuel system component failures may cause a no start, or prevent the engine from running. It is im por t an t t o k now t h at t h e E CM h a s a fea t ur e where, if possible, it will ignore the failed sensor, set a code related to the sensor, and operate the engine in a “Limp Home” mode. When t he ECM is operating in a “Limp Home” mode, the Check Engine Lamp on the instrument panel may be constantly illuminated, and the engine will most likely have a noticeable loss of p er for m a n ce . A n e xa m p le of t h is w ou ld b e a n Accelerator Pedal Position Sensor failure, and in that s it u a t i on , t h e e n gi n e w ou l d r u n a t a con s t a n t 11 00 RPM, regardless of the actual position of the pedal. This is the most extreme of the three “Limp Home” modes. When the Check Engine Lamp is illuminated constantly with the key on and the engine running, it

FUEL INJECTION SYSTEM DESCRIPTION This section will cover components either regulated or controlled by the ECM contr oller and the Powert r a i n C on t r o l M od u l e ( P C M). T h e fu e l h e a t e r r e la y and fuel heater are not operated by the ECM controller or the PCM. These components are controlled by th e ignition (key) switch. All other fuel system elect r i ca l com p on e n t s n e ce s sa r y t o op e r a t e t h e e n gi n e are controlled or regulated by t he ECM controller, which interfaces with the PCM. Refer to t he following description for more informa tion.

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DESCRIPTION AND OPERATION (Continued) usually indicates a problem has been detected somewhere within the fuel system. The DRBIII scan tool is the best method for communicating with the ECM and PCM to diagnose faults within the system.

POWERTRAIN CONTROL MODULE (PCM) DESCRIPTION On LHD vehicles, the ECM is mounted behind the lower Instrument Panel to the right of the accelerat or p ed a l (F ig . 1 ). O n R H D v eh i cle s, t h e E C M i s m ou n t e d b e h i n d t h e l ow er I n s t r u m e n t P a n e l t o t h e left of the clutch pedal. The Powertrain Control Modu l e ( P C M) i s m ou n t e d i n t h e e n gi n e c om p a r t m e n t . (Fig. 2).

Fig. 2 PCM Location—LHD 1 2 3 4

Fig. 1 ECM Location—LHD 1 2 3 4

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ECM HARNESS CONNECTOR C1 ENGINE CONTROL MODULE (ECM) ECM HARNESS CONNECTOR C2 ACCELERATOR PEDAL POSITION SENSOR

The ECM Controller is a pre–programmed, digital computer. It will either directly operate or partially regulate the: • Speed Control • Speed Control lamp • Fuel Timing Solenoid • Check Engine Light • Glow Plug Relay • Glow Plugs • Glow Plug Lamp • ASD Relay • Air Condit ionin g • Tachometer • Electric Vacuum Modulator (EVM) T he E C M ca n a d ap t it s p r ogr a m m in g t o m ee t changing operating conditions.

– – – –


T h e E C M r e ce iv es in p u t s ign a ls fr om va r iou s s wit ch e s a n d s en s or s . B a se d on t h e se i np u t s, t h e ECM regulates various engine and vehicle operations through different system components. These compon e n t s a r e r e f e r r e d t o a s E C M O u t p u t s . The sensors a n d s wit ch e s t h a t p r ovi de in p u t s t o t h e E C M a r e considered E C M I n p u t s . E C M In p u t s a r e : • Air Conditioning Selection • Theft Alarm • ASD Relay • Control Sleeve Position Sensor • Fuel Temperature Sensor • Mass Air Flow Sensor • Accelerator Pedal Position Sensor Sensor • Engine Coolant Temperature • Low Idle Position Switch • 5 Volt Supply • Vehicle Speed Sensor • Engine Speed/Crank Position Sensor (rpm) • Needle Movement Sensor • Starter Signal • Brake Switch • Speed Control Switch • Power Ground • Ignition (key) Switch Sense ECM Outputs: Aft e r i n p u t s a r e r e ce iv ed b y t h e E C M a n d P C M, ce r t a in s e n sor s , s w it ch e s a n d com p on e n t s a r e con trolled or regulated by the ECM and PCM. These are considered E C M O u t p u t s . These outputs are for: • A/C Clutch Relay (for A/C clutch operat ion)

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DESCRIPTION AND OPERATION (Continued) Speed Control Lamp ASD Relay • 5 Volts Supply • Fuel Quantity Actuator • Fuel Timing Solenoid • Fuel Shutdown Solenoid • Glow Plug Lamp • Check Engine Lamp (“On/Off” signal) • Electric Vacuum Modulator (EVM) • Glow Plug Relay • Tachometer The PCM sends and recieves signals to and from the ECM controller. P C M i n p u t s a r e : • Power Gound • 5 Volts Supply • Vehicle Speed Sensor • Water-In-Fuel Sensor • Coolant Temperature Sensor • Low Coolant Sensor • Sensor Return • Fuel Level Sensor • Oil Pressure Sensor • Tachometer Signal • Glow Plug Lamp • Check Engine Lamp (“On/Off” signal) • Brake On/Off Switch • Battery Voltage • ASD Relay PCM Outputs: • A/C On Signal • Vehicle Theft Alarm “Ok to Run” signal • Body Control Module CCD Bus (+) • Body Control Module CCD Bus (–) • Scan Tool Data Link Recieve • Scan Tool Data Link Transmit • Low Coolant Lamp • Generator Control • •

BOOST PRESSURE SENSOR DESCRIPTION The Boost Pressure Sensor is mounted to th e top of the intake manifold (Fig. 3). It is a sensor that measures both manifold vacuum and turbo boost, and it a l so c on t a i n s a n i n t eg r a t e d i n t a k e a i r t e m p er a t u r e sensor. The Boost Pressure Sensor takes the place of the Mass Air Flow (MAF). In the Intake Air Temperature Sensor component, there is a ceramic element t h a t ch a n ge s it s r e sis t a n ce b a se d on t e m pe r a t u re . The ceramic element is par t of an electronic circuit connected to the PCM, and has a voltage applied to it. The ceramic element is exposed to the air inside t h e in t a ke . T his a ir h a s a coolin g e ffe ct on t h e ce r a m ic e le m en t , a n d i t s r e s is t a n ce ch a n g e s. T h is ca u s e s t h e v ol t a ge fl ow in g t h r o u gh t h e i n t a k e a i r temperatur e circuit to vary. The voltage signal pro-

duced by the Intake Air Temperature Sensor changes inversely to the temperature, and is measured by the PCM. As a general rule, when the temperature of the air in the intake is high, the voltage signal produced b y t h e I n t a k e A ir Te m p er a t u r e S e n sor i s l ow. T h e com p on e n t of t h e B oos t P r e s su r e S e n sor t h a t m e a s u r e s m a n i fol d v a cu u m a n d t u r b o b oos t p r od u ce s a voltage signal that is proportional to the pressure in the intake manifold. When the intake manifold pressure is low, the voltage is low, and when the pressure is high, the voltage is high. The PCM uses the voltage signals from the Boost Pressure Sensor, and the I n t a ke Air Te m pe r a tu r e S en s or t o d et e r m in e t h e amount of air flowing through the intake manifold.

Fig. 3 Boost Pressure Sensor Location 1 – BOOST PRESSURE SENSOR HARNESS CONNECTOR 2 – BOOST PRESSURE SENSOR

VEHICLE THEFT ALARM DESCRIPTION T h e P C M ca n l ea r n i f t h e v eh i cl e h a s a Ve h icl e Theft Alarm (VTA) system. Once it detects the vehicle having VTA, t h e c o n tr ol le r c a n ON LY B E USED ON VEHICLES WITH VTA. If the PCM is put it on a vehicle without VTA the Glow Plug Lamp will start to blink and the vehicle will not start. The PCM cannot be flashed to remove the VTA.

BATTERY VOLTAGE—PCM INPUT DESCRIPTION T h e b a t t e r y v ol t a ge i n pu t p r ov id e s p ow er t o t h e PCM. It also informs the PCM what voltage level is being supplied by th e generator once th e vehicle is running.

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DESCRIPTION AND OPERATION (Continued) The battery input also provides the voltage that is needed to keep the PCM memory alive. The memory s t or e s D ia g n os t ic Tr ou b le C od e (D TC ) m e s sa g es . Trouble codes will still be stored even if the battary voltage is lost.

FUEL INJECTOR SENSOR— GROUND

SENSOR RETURN—ECM/PCM INPUT (ANALOG GROUND) DESCRIPTION Sensor Return provides a low noise Analog ground reference for all system sensors.

IGNITION CIRCUIT SENSE— ECM/PCM INPUT DESCRIPTION T h e i gn i t ion ci r cu i t s e n se i n pu t s ig n a ls t h e E C M a n d P C M t h a t t h e ig ni tion (k ey) s wit ch h a s b ee n t u r n e d t o t h e O N p o s i t i o n . T h i s s i g n a l i n i t i a t e s t he g low p lu g con t r o l r ou t i n e t o b eg in t h e “p r e –h e a t ” cycle.

IGNITION CIRCUIT SENSE— PCM INPUT

Fig. 4 Fuel Injector Sensor 1 2 3 4

– – – –


T h e i gn i t ion ci r cu i t s e n se i n pu t s ig n a ls t h e P C M that the ignition (key) switch has been turned to the ON position. This signal initiates the glow plug control routine to begin the “pre–heat” cycle.

DESCRIPTION

POWER GROUND

Provides a low noise ground for the fuel injector sens or only.

DESCRIPTION Provides a common ground for power devices (solenoid and relay devices).

NEEDLE MOVEMENT OR INTRUMENTED FIRST INJECTOR— ECM INPUT DESCRIPTION T h is i n pu t fr om t h e E C M s u p p li es a con s t a n t 3 0 mA electrical current source for the first injector sens or . I t w il l v a r y t h e v ol t a ge t o t h i s s e n s or w h e n i t s e n se s a m e ch a n i ca l m ov em e n t w it h i n t h e i n je ct or needle (pintle) of the number–1 cylinder fuel injector. When this voltage has been determined by the ECM, it will then control an output to the fuel timing solenoid (the fuel timing solenoid is located on the fuel injection pu mp). Also refer to F uel In jection Pu mp for additional information. The first injector sensor is a magnetic (inductive) type. T h e fi r st i n je ct or s e n sor i s u s e d o n ly on t h e fu e l injector for the number–1 cylinder (Fig. 4). It is n ot used on the injectors for cylinders number 2, 3, or 4.

ENGINE COOLANT TEMPERATURE SENSOR— ECM/PCM INPUT DESCRIPTION The 0–5 volt input from this sensor tells the ECM a n d P C M t h e t e mp er a t u r e of t h e e n gin e cool a nt . B a s ed on t h e v ol t a ge r e ce iv ed a t t h e E C M , i t w il l then determine operation of the fuel timing solenoid, glow plug r elay, electrical vacuum modulator (emission component) and generator (charging system). The sensor is located on the side of the #3 cylinder head near the rear of fuel injection pump (Fig. 5).

ENGINE SPEED SENSOR— ECM INPUT DESCRIPTION The engine speed sensor is mounted to the transmission bellhousing at the left/rear side of the engine block (Fig. 6). The engine speed sensor produces its own output signal. If this signal is not received, the ECM will not allow the engine to start. The engine speed sensor input is used in conjunct i on w it h t h e fi r st i n je ct or s e n sor t o e s t a bl is h fu e l injection pump timing.

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– – – –

PCM ENGINE COOLANT TEMPERATURE (ECT) SENSOR ECM ENGINE COOLANT TEMPERATURE (ECT) SENSOR ECM ECT SENSOR HARNESS CONNECTOR PCM ECT SENSOR HARNESS CONNECTOR

Fig. 7 Speed Sensor Operation 1 – ENGINE SPEED SENSOR 2 – FLYWHEEL 3 – NOTCHES

of t h e g en e r a t or fi el d, v eh i cl e s p ee d con t r o l, a n d instrument panel mounted tachometer. If the engine speed sensor should fail, the system is unable to compensate for the problem and the car will stop.

AIR CONDITIONING (A/C) CONTROLS—ECM INPUTS DESCRIPTION

Fig. 6 Engine Speed Sensor Location 1 2 3 4 5

– – – – –

ENGINE SPEED SENSOR GROMMET MOUNTING BOLT(S) LEFT REAR OF ENGINE TRANSMISSION

T h e fl yw h e el h a s fou r n ot ch e s a t i t s o u t e r e d ge (Fig. 7). Each notch is spaced equally every 90°. The n ot ch e s ca u s e a p u ls e t o b e ge n er a t e d w h en t h e y p a s s u n d e r t h e s p ee d s e n sor (F i g. 7 ). T h es e p u l se s are the input to the ECM. The input from this sensor determines crankshaft position (in degrees) by monitoring the notches. T h e s e n sor a ls o g en e r a t es a n r p m s ign a l t o t h e ECM. This signal is used as an input for the control

The A/C control system information applies to factory installed air conditioning units. A/C REQUEST SIGNAL: When either the A/C or Defrost mode has been selected and the A/C low and high–pressure switches are closed, an input signal is sent to the ECM. The ECM uses this input to cycle the A/C compressor through the A/C relay. If the A/C low or high–pressure switch opens, the E C M w il l n o t r e ce iv e a n A/C r e q u es t s ig n a l. T h e PCM will then remove the ground from the A/C relay. This will deactivate the A/C compressor clutch. Also, if the engine coolant reaches a temperatur e outside normal of its normal range, or it overheats, the ECM will deactivate the A/C clutch.

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BRAKE SWITCH— ECM INPUT DESCRIPTION When the brake light switch is activated, the ECM r ece ives a n in p ut in d ica t in g t h a t t h e b ra k es a r e being applied. After receiving this input, the ECM is used to control the speed control system. There is a Primary and a Secondary brake switch. The Seconda r y b r a k e s w i t ch i s c los e d u n t i l t h e b r a k e p e d a l i s pressed.

DATA LINK CONNECTOR— PCM AND ECM INPUT AND OUTPUT The 16–way data link connector (diagnostic scan t ool con n e ct or ) l in k s t h e D ia g n os t ic R ea d ou t B ox (DRB) scan tool with the PCM and ECM. The data link connector is located under the instrument panel near the left body side cowl panel on left hand drive vehicles (Fig. 8). And near the right body side cowl panel on right hand drive vehicles (Fig. 9).

Fig. 8 Data Link Connector Location – LHD 1 – 16–WAY DATA LINK CONNECTOR

VEHICLE SPEED SENSOR— ECM INPUT The vehicle speed sensor is located in the transfer case extension housing (Fig. 10). The sensor input is used by t he ECM t o determine vehicle speed a nd distan ce traveled. T h e s p ee d s e n sor g en e r a t e s 8 p u ls e s p e r s e n sor r e vol u t ion . T h e se s ig n a ls , i n con j u n ct i on w it h a closed throttle signal from the accelerator pedal position sensor, indicate an idle deceleration to the ECM. When the vehicle is stopped at idle, a released pedal s ig n a l i s r e ce iv ed b y t h e E C M (b u t a s p ee d s e n sor signal is not received).

Fig. 9 Data Link Connector Location –RHD 1 – DATA LINK CONNECTOR

Fig. 10 Vehicle Speed Sensor—4 Wheel Drive 1 – 4WD TRANSFER CASE EXTENSION 2 – VEHICLE SPEED SENSOR 3 – SENSOR ELECTRICAL CONNECTOR

I n a d d it i on t o d e t er m i n in g d is t a n ce a n d v eh i cl e speed, the output from the sensor is used to control speed control operation.

SPEED CONTROL—ECM INPUT DESCRIPTION T h e s p ee d con t r ol s ys t em p r ovid es fiv e s ep a r a t e inputs to the ECM: On/Off, Set, Resume/Accel, Cancel, and Decel.. The On/Off input informs the ECM tha t the speed control system has been activated. The Set input

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DESCRIPTION AND OPERATION (Continued) i n for m s t h e E C M t h a t a fi xe d v e h icl e s p e ed h a s b ee n selected. The Resume input indicates to the ECM that the previous fixed speed is requested. Speed control operation will start at 50 km /h–142 km/h (35–85 mph ). The upper range of operation is n ot r e s t r ict e d b y v eh i cl e s p ee d . I n p u t s t h a t e ffe ct speed control operation are vehicle speed sensor and accelerator pedal position sensor. Refer to Group 8H for furt her speed control information.

ASD RELAY— ECM INPUT DESCRIPTION A 12 volt signal at this input indicates to the ECM t h a t t h e AS D r e la y h a s b ee n a ct iv a te d. T h e AS D relay is located in the PDC. The PDC is located next t o t h e b a t t er y in t h e e n gin e com p a r t m en t . F or t h e location of the relay within the PDC, refer to label on PDC cover. This input is used only to sense that the ASD relay is energized. If the ECM does not see 12 volts (+) at this input when t he ASD r elay should be activated, it will set a Diagnostic Trouble Code (DTC).

SPEED CONTROL— PCM OUTPUTS DESCRIPTION These two circuits control the fuel quantity actuator to r egulate vehicle speed. Refer to Group 8H for Speed Control information.

AIR CONDITIONING RELAY— ECM OUTPUT DESCRIPTION This circuit controls a ground signa l for opera tion of the A/C clutch relay. Also refer to Air Conditioning (A/C) Controls—ECM Input for additional information. The A/C relay is located in the Power Distribution Center (PDC). The PDC is located next to t he bat tery i n t h e e n gi n e c om p a r t m e n t . F or t h e l oca t i on of t h e relay within the PDC, refer to label on PDC cover.

TIMING SOLENOID— ECM OUTPUT DESCRIPTION The timing solenoid is located on the bottom of the fuel injection pump (Fig. 12).

FIVE VOLT POWER—ECM/PCM OUTPUT DESCRIPTION T h is cir cu it s u pp lie s a p p roxi ma t e ly 5 v ol ts t o power the Accelerator Pedal Position Sensor, and the Boost Pressure Sensor.

ENGINE COOLANT GAUGE— PCM OUTPUT DESCRIPTION Refer to the Instrument Panel and Gauges group for additional information.

ENGINE OIL PRESSURE GAUGE— PCM OUTPUT DESCRIPTION Refer to the Instrument Panel and Gauges group for additional information.

GLOW PLUG LAMP— PCM OUTPUT DESCRIPTION The Glow Plug lamp (malfunction indicator lamp) illuminates on t he message center each time th e ignit i on (k e y) s w it ch i s t u r n e d on . I t w il l s t a y on for about two seconds as a bulb test.

Fig. 11 Glow Plug Lamp Symbol

Fig. 12 Timing Solenoid 1 2 3 4 5 6

– – – – – –


This 12(+) volt, p ulse width modulated (duty–cycle) output controls the amount of fuel timing (advance) in the fuel injection pump. The higher the duty–cycle, the lower the advance. The lower the duty–cycle, the more advanced the fuel timing.

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DESCRIPTION AND OPERATION (Continued) T h e d u t y –cy cl e i s d e t er m i n ed b y t h e E C M fr om inputs it receives from t he fuel injector sensor and engine speed sensor.

TACHOMETER— PCM OUTPUT DESCRIPTION T h e P C M r e cie ve s e n gi n e r p m va lu e s fr om t h e ECM controller, and then supplies engine rpm values to the Body Controller that then supplies the instrument cluster mounted tachometer (if equipped). Refer to Group 8E for tachometer informat ion.

GLOW PLUG RELAY— ECM OUTPUT DESCRIPTION When the ignition (key) switch is placed in the ON position, a signal is sent to the ECM relating current engine coolant temperature. This signal is sent from the engine coolant temperature sensor. After receiving this signal, the ECM will determine i f, w h e n a n d for h ow l on g a p e r iod t h e g low p lu g relay should be activated. This is done before, during a n d a ft e r t h e e n gi n e i s s t a r t e d . W h en e ve r t h e g low plug relay is a ctivated, it will control th e 12V+ 100 amp circuit for the operation of the four glow plugs.

I n t h is ch a r t , P r e – H ea t a n d P os t –H e a t t im e s a r e mentioned. Pre–heat is the amount of time the glow plug relay circuit is activated when the ignition (key) switch is ON, but the engine has yet to be started. Post–heat is the amount of time the glow plug relay circuit is activated after the engine is operating. The G low P l u g l a m p w il l n o t b e i l lu m i n a t e d d u r i n g t h e post–heat cycle.

GLOW PLUG CONTROL

ENGINE WAIT-TOCOOLANT START TEMPLAMP ON ERATURE (SECONDS) KEY ON

PRE-HEAT CYCLE POST(GLOW HEAT PLUGS CYCLE ON) (SECONDS) (SECONDS)

-30 C

15 SEC.

45 SEC.

200 SEC.

-10 C

8 SEC.

35 SEC.

180 SEC.

+10 C

6 SEC.

25 SEC.

118 SEC.

+30 C

5 SEC.

20 SEC.

70 SEC.

+40 C

4 SEC.

16 SEC.

60 SEC.

+70 C

3 SEC.

16 SEC.

20 SEC.

GLOW PLUGS DESCRIPTION G low p lu g s a r e u s e d t o h e lp s t a r t a col d o r cool engine. The plug will heat up and glow to heat the combust ion cha mber of each cylinder. An ind ividual plug is used for each cylinder. Each plug is threaded into th e cylinder head above th e fuel injector (Fig. 14).


With a cold engine, the glow plug relay a nd glow p lu g s m a y b e a c t iv a t ed for a m a x im u m t i m e o f 2 00 seconds. Refer to the following Glow Plug Contr ol chart for a temperature/time comparison of glow plug relay operation.

Fig. 14 Glow Plug 1 – GLOW PLUG

Each plug will momentarily draw approximately 25 amps of electrical curr ent during the initial key–on

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DESCRIPTION AND OPERATION (Continued) cycle. Th is is on a cold or cool en gine. After heat ing, t h e cu r r e n t d r a w w il l d r op t o a p p r ox im a t e ly 9 –1 2 amps per plug. Total momentary current draw for all four plugs is approximately 100 amps on a cold engine dropping to a total of approximately 40 amps after the plugs are heated. E l ect r i ca l op e r a t ion of t h e g low p lu g s a r e con trolled by the glow plug relay. Refer to the previous Glow Plug Relay—ECM Output for additional information.

ELECTRIC VACUUM MODULATOR (EVM)— ECM OUTPUT DESCRIPTION This circuit contr ols operat ion of the Electric Vacuu m Modulat or (EVM). The EVM cont rols operat ion of the EGR valve. Refer to Group 25, Em ission Control System for information. See Electric Vacuum Modulator.

DIAGNOSIS AND TESTING


– – – –

PCM ECM ECM PCM

ENGINE COOLANT TEMPERATURE (ECT) SENSOR ENGINE COOLANT TEMPERATURE (ECT) SENSOR ECT SENSOR HARNESS CONNECTOR ECT SENSOR HARNESS CONNECTOR

DIESEL DIAGNOSTICS The ECM controllers perform engine off diagnostic tests, which may be heard for about 60 seconds after turning the key off.

ASD RELAY TEST To perform a test of the relay and its related circuitry, r efer to th e DRB scan tool. To test the relay only, refer to Relays—Operat ion/Testing in this section of the group. D i a g n o s t i c Tr o u b le C o d e s : Refer to On-Board Diagnostics in Group 25, Em ission Control System for a list of Diagnostic Trouble Codes (DTC’s) for certain fuel system components.

ENGINE SPEED SENSOR TEST To p e r for m a t e s t of t h e e n gi n e s p e ed s e n sor a n d i t s r e la t e d ci r cu i t r y, r e fe r t o t h e 3 .1 L P ow er t r a i n Diagnostic Procedures Manual. D i a g n o s t i c Tr o u b le C o d e s : Refer to On-Board Diagnostics in Group 25, Em ission Control System for a list of Diagnostic Trouble Codes (DTC’s) for certain fuel system components.

ENGINE COOLANT TEMPERATURE SENSOR TEST The sensor is located on the side of cylinder head near the rear of fuel injection pump (Fig. 15). For a list of Diagnostic Trouble Codes (DTC’s) for certain fuel system components, refer to On-Board

Diagnostics in Group 25, Em ission Control System. To test the sensor only, refer to the following: (1) Disconnect wire h arn ess connector from coolan t temperature sensor. (2 ) Te s t t h e r e s is t a n ce of t h e s e n sor w it h a h i gh input impedance (digital) volt–ohmmeter. The resist a n ce (a s m e a su r e d a cr os s t h e s en s or t e r min a ls ) s hou ld b e le ss t h a n 1 34 0 oh m s w it h t h e e ngin e w a r m . R efe r t o t h e follow in g S en s or R es is t a n ce (OHMS) chart. Replace the sensor if it is not within the range of resistance specified in the chart. (3 ) Te s t con t i n u it y of t h e w ir e h a r n e s s . D o t h i s b et w ee n t h e E C M w ir e h a r n e ss con n e ct or a n d t h e s en s or con n e ct or t e r m in a l . Al so t e s t con t i n u it y of wire harness to the sensor connector terminal. Refer to Group 8W for wiring connector and circuitry information. Repair the wire harness if an open circuit is indicated. (4) After tests are completed, connect electrical connector to sensor.

GLOW PLUG TEST Hard starting or a rough idle after starting may be caused by one or more defective glow plugs. Before testing the glow plugs, a test of the glow plug relays should be performed. This will ensure tha t 12V+ is a v a ila b le a t t h e p lu g s w h en s t a r t in g t h e e n gin e . Refer to the Glow Plug Relay Test for information. For accurate test results, the glow plugs should be removed from the engine. The plugs must be checked

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DIAGNOSIS AND T ESTING (Continued) SENSOR RESISTANCE (OHMS) SENSOR RESISTANCE (OHMS)—COOLANT TEMPERATURE SENSOR/INTAKE AIR TEMPERATU RE SENSOR

TEMPERATURE

RESISTANCE (OHMS)

C

F

MIN

MAX

−40

−40

291,490

381,710

−20

−4

85,850

108,390

−10

14

49,250

61,430

0

32

29,330

35,990

10

50

17,990

21,810

20

68

11,370

13,610

25

77

9,120

10,880

30

86

7,370

8,750

40

104

4,900

5,750

50

122

3,330

3,880

60

140

2,310

2,670

70

158

1,630

1,870

80

176

1,170

1,340

90

194

860

970

100

212

640

270

110

230

480

540

120

248

370

410

when cold. D o n o t c h e c k t h e p l u g s i f t h e e n g i n e h as re ce ntly be en o pe ra te d. If p lu gs a re c he ck ed w h e n w a rm , i nc orre ct a mp g au ge readings will result. U s e C h u r ch ill G low P lu g Te st e r D X. 90 0 or a n e qu i va l en t (F i g. 1 6) for t h e fol low in g t e s t s. T h is tester is equipped with 4 timer lamps. (1) Remove the glow plugs from the engine. Refer to Glow Plug Removal/Installation. (2 ) A t t a ch t h e r e d l e a d o f t h e t e s t er t o t h e 1 2V+ (positive) side of the battery. (3) Attach the black lead of the tester to the 12V– (negative) side of the battery. (4) Fit the glow plug into the top of the tester and secure it with the spring loaded bar (Fig. 16). (5) Attach the third lead wire of the tester to the electrical terminal at the end of the glow plug. (6 ) Wh e n p er for m in g t h e t e st , t h e t e st e r b u t t on (Fig. 16) should be held continuously without release for 2 0 s e con d s a s i n di ca t e d b y t h e 4 t i m er l a m p s. E a c h i ll u m in a t e d l a m p r e p r es en t s a 5 s econ d t i m e lapse. (a ) P r e ss a n d h old t h e t e st e r b u t t on (F ig. 1 6) and note the amp gauge reading. The gauge read-

Fig. 16 Typical Glow Plug Tester 1 2 3 4 5 6

– – – – – –

INSERT GLOW PLUG HERE OBSERVATION WINDOW SPRING LOADED BAR TIMER LAMPS (4) TEST LEADS TESTER BUTTON

i n g s h ou l d i n di ca t e a m om e n t a r y, i n it i a l cu r r e n t draw (surge) of approximately 25 amps. After the initial surge, the amp gauge reading should begin to fall off. The glow plug tip should start to glow an orange color after 5 seconds. If the tip did not glow after 5 seconds, replace the glow plug. Before discarding the glow plug, check the position of the circuit breaker on the bottom of the plug tester. It may have to be reset. Reset if necessary. (b ) C on t in u e t o h old t h e t e st e r b u t t on w h ile observing the amp gauge and the 4 timer lamps. When all 4 lamps are illuminated, indicating a 20 second time lapse, the amp gauge reading should i n di ca t e a 9 –1 2 a m p cu r r e n t d r a w. I f n o t , r e p la ce the glow plug. Refer to Glow Plug Removal/Installation. (7) Check each glow plug in t his man ner using one 20 second cycle. If the glow plug is to be retested, it must first be allowed to cool to room temperature.

WARNING: THE GLOW PLUG WILL BECOME EXTREMELY HOT (GLOWING) DURING THESE TESTS. BURNS COULD RESULT IF IMPROPERLY HANDLED. ALLOW THE GLOW PLUG TO COOL BEFORE REMOVING FROM TESTER. (8) Remove th e glow plug from the tester.

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GLOW PLUG RELAY TEST The glow plug relay is located in the engine compartment on the left–inner fender (Fig. 17).

10–12 volts + at each electrical connector. 10–12 volts + should be at each connector whenever the ECM is operating in the pre–heat or post–heat cycles (refer to the following Glow Plug Control chart). B e v e r y c are fu l n o t t o a llo w a n y o f t h e fo u r d i sc on n e c t e d g l o w p l u g e l e c t ri c a l c o n n e c t or s t o c o n tact a metal surface. When the key is turned to the ON position, approximately 100 amps at 12 v o lt s i s s u p p l i e d t o t h e s e c o n n e c t or s . If 10–12 volts + is not available at each connector, check continuity of wiring harn ess directly t o th e relay. If continuity is good directly to the relay, the fault is either with the relay or the relay input from the ECM. To test th e r elay only, r efer to Relays—Operat ion/Testi n g i n t h i s s e ct i on of t h e g r ou p . I f t h e r e la y t e s t i s good, refer to the DRB scan tool. D i a g n o s t i c Tr o u b le C o d e s : Refer to On-Board Diagnostics in Group 25, Em ission Control System for a list of Diagnostic Trouble Codes (DTC’s) for certain fuel system components.


When the ignition (key) switch is placed in the ON position, a signal is sent to the ECM relating current engine coolant temperature. This signal is sent from the engine coolant temperature sensor. After receiving this signal, the ECM will determine i f, w h e n a n d for h ow l on g a p e r iod t h e g low p lu g relay should be activated. This is done before, during a n d a ft e r t h e e n gi n e i s s t a r t e d . W h en e ve r t h e g low plug relay is a ctivated, it will control th e 12V+ 100 amp circuit for the operation of the four glow plugs. The Glow Plug lamp is tied to this circuit. Lamp operation is also controlled by the ECM. With a cold engine, the glow plug relay a nd glow p lu g s m a y b e a c t iv a t ed for a m a x im u m t i m e o f 2 00 seconds. Refer to the Glow Plug Control chart for a temperature/time comparison of glow plug relay operation. I n t h is ch a r t , P r e –H e a t a n d P os t –H e a t t im e s a r e mentioned. Pre–heat is the amount of time the glow plug relay circuit is activated when the ignition (key) switch is ON, but the engine has yet to be started. Post–heat is the amount of time the glow plug relay circuit is activated after the engine is operating. The G low P l u g l a m p w il l n o t b e i l lu m i n a t e d d u r i n g t h e post–heat cycle. TESTING: Disconnect and isolate the electrical connectors (Fig. 18) at all four glow plugs. With the engine cool or col d, a n d t h e k e y i n t h e O N p os it i on , ch e ck for

Fig. 18 Wiring Connection at Glow Plug 1 – GLOW PLUG ELECTRICAL CONNECTOR

GLOW PLUG CONTROL

ENGINE WAIT-TOCOOLANT START TEMPLAMP ON ERATURE (SECONDS) KEY ON

PRE-HEAT CYCLE POST(GLOW HEAT PLUGS CYCLE ON) (SECONDS) (SECONDS)

-30 C

15 SEC.

45 SEC.

200 SEC.

-10 C

8 SEC.

35 SEC.

180 SEC.

+10 C

6 SEC.

25 SEC.

118 SEC.

+30 C

5 SEC.

20 SEC.

70 SEC.

+40 C

4 SEC.

16 SEC.

60 SEC.

+70 C

3 SEC.

16 SEC.

20 SEC.

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RELAYS— OPERATION/TESTING T h e f ol lo w i n g d e s c ri p ti o n o f o p e r a t io n a n d tests apply only to the ASD and other relays . The terminals on the bottom of each relay are numbered (Fig. 19).

(3 ) C on n e ct t h e oh m m e t e r b et w e en t e r m in a l s 3 0 a n d 8 7A. T h e oh m m e te r s h ou ld s h ow con t in u it y between terminals 30 and 87A. (4 ) C on n e ct t h e oh m m e t e r b et w e en t e r m in a l s 8 7 and 30. The ohmmeter should not show continuity at this time. (5) Connect one end of a jumper wire (16 gauge or smaller) to relay terminal 85. Connect the other end of t h e ju m p e r w ir e t o t h e g r ou n d s id e o f a 1 2 v ol t power source. (6 ) C on n e ct on e e n d of a n ot h e r ju m p e r w ir e (1 6 g a u ge or s m a l le r ) t o t h e p ow er s id e of t h e 1 2 v ol t power source. D o n o t a t t a c h t h e o t h e r e n d o f t h e jumper wire to the relay at this time.

WARNING: DO NOT ALLOW OHMMETER TO CONTACT TERMINALS 85 OR 86 DURING THIS TEST.


OPERATION Terminal number 30 is connected to battery voltage. For both the ASD and other relays, terminal 30 is connected to battery voltage at all times. E C M gr ou n ds t h e coil s id e of t h e r ela y • T he t h r o u gh t e r m in a l n u m b e r 8 5. • Terminal number 86 supplies voltage to the coil side of the relay. • When the PCM de-energizes the ASD and other relays, term inal nu mber 87A connects to terminal 30. This is the Off position. In the off position, voltage is not supplied to the rest of the circuit. Terminal 87A is the center terminal on the relay. t h e E C M e n er giz es t h e A S D a n d ot h e r • Wh e n relays, terminal 87 connects to terminal 30. This is the On position. Terminal 87 supplies voltage to the rest of th e circuit.

(7 ) At t a ch t h e ot h e r e n d of t h e ju m p er w ir e t o relay terminal 86. This activates the relay. The ohmmeter should now show continuity between r elay term i n a ls 8 7 a n d 3 0. T h e oh m m e t e r s h ou l d n o t s h ow continuity between relay terminals 87A and 30. (8) Disconnect jumper wires. (9) Replace the relay if it did not pass the continuity and resistance tests. If the relay passed the tests, it operates properly. Check the remainder of the ASD and other relay circuits. Refer to group 8W, Wiring Diagrams.

BOOST / PRESSURE SENSOR

•

TESTING T h e fol low in g p r oce d u r e a p p li es t o t h e AS D a n d other relays. (1) Remove r elay from conn ector before test ing. (2) With the relay removed from the vehicle, use an ohmmeter to check the resistance between terminals 85 and 86. The resistance should be between 75 5 ohms.

Fig. 20 Boost Pressure Sensor Location 1 – BOOST PRESSURE SENSOR HARNESS CONNECTOR 2 – BOOST PRESSURE SENSOR

If the boost pressure sensor fails, the PCM records a D TC in t o m e mor y a n d con t in u e s t o o pe r a t e t h e

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DIAGNOSIS AND T ESTING (Continued) engine in one of the three “limp-in” modes. When the PCM is operating in this mode, a loss of power will be present, as if the turbocharger was not operating. The best method for diagnosing faults with the boost pressure sensor is with the DRB III scan tool. D i a g n o s t i c Tr o u b le C o d e s : Refer to On-Board Diagnostics in Group 25, Emission Control System for a list of Diagnostic Trouble Codes (DTC’s) for certa in fuel system components.

VEHICLE SPEED SENSOR TEST To perform a test of the sensor and its related circuitry, refer to DRB scan tool. D i a g n o s t i c Tr o u b le C o d e s : Refer to On-Board Diagnostics in Group 25, Em ission Control System for a list of Diagnostic Trouble Codes (DTC’s) for certain fuel system components.

DIAGNOSTIC TROUBLE CODES For a list of Diagnostic Trouble Codes (DTC’s), refer to Group 25, Emission Control System for information. See On-Board Diagnostics.

Fig. 21 Engine Speed Sensor 1 2 3 4 5

– – – – –

ENGINE SPEED SENSOR GROMMET MOUNTING BOLT(S) LEFT REAR OF ENGINE TRANSMISSION

ENGINE COOLANT TEMPERATURE SENSOR REMOVAL AND INSTALLATION ASD RELAY The ASD relay is located in the PDC. For the locat i on of t h e r e la y w it h i n t h e P D C , r e fe r t o l a b el on PDC cover.

A/C CLUTCH RELAY The A/C clutch relay is located in the PDC. For the location of the relay within the PDC, refer to label on PDC cover.

ENGINE SPEED SENSOR The engine speed sensor is mounted to the transmission bellhousing a t the rear of th e engine block (Fig. 21).

REMOVAL (1 ) D is con n e ct t h e h a r n e s s (on t h e s e n sor ) fr om the main electrical harness. (2) Remove the sensor mounting bolts. (3) Remove the sensor.

INSTALLATION (1) Install the sensor flush against the opening in the transmission housing. (2) Install and tighten the sensor mounting bolt to 19 N·m (14 ft. lbs.) torque. (3) Connect the electrical connector to the sensor.

The sensor is located on the side of cylinder head near the rear of fuel injection pump.

REMOVAL WARNING: HOT, PRESSURIZED COOLANT CAN CAUSE INJURY BY SCALDING. COOLING SYSTEM MUST BE PARTIALLY DRAINED BEFORE REMOVING THE COOLANT TEMPERATURE SENSOR. REFER TO GROUP 7, COOLING. (1) Part ially dra in cooling system. Refer to Group 7, Cooling. (2) Disconnect electrical connector from sen sor. (3) Remove sensor from cylinder h ead.

INSTALLATION (1) Install a new copper gasket to sensor. (2) Install sensor to cylinder h ead. (3) Tighten sensor to 18 N·m (13 ft. lbs.) torque. (4) Connect electr ical connector to sensor. (5) Replace an y lost engine coolan t. Refer to Group 7, Cooling System.

GLOW PLUGS The glow plugs are located above each fuel injector (Fig. 22). Four individual plugs are used.

REMOVAL (1 ) D is con n e ct t h e n e ga t i ve b a t t e r y ca b le a t t h e battery. (2) Clean the a rea a round th e glow plug with compressed air before removal.

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Fig. 22 Glow Plug 1 – GLOW PLUG


REMOVAL (1 ) D is con n e ct t h e n e ga t i ve b a t t e r y ca b le a t t h e battery. (2) Remove r elay mount ing bolt. (3 ) D is con n e ct e le ct r i ca l con n e ct or a t r e la y a n d remove relay.

INSTALLATION

Fig. 23 Glow Plug Electrical Connector 1 – GLOW PLUG ELECTRICAL CONNECTOR

(1) Check condition of electr ical connector for dam age or corrosion. Repair as necessary. (2) Insta ll electr ical connector to r elay. (3) Install relay t o inner fender. (4) Connect battery cable to battery.

POWERTRAIN CONTROL MODULE (PCM) (3) Disconn ect electrical conn ector (Fig. 23) at glow plug. (4) Remove the glow plug (Fig. 22) from cylinder head.

INSTALLATION

The PCM is mounted to a bracket mounted to the i n n er s id e of t h e r igh t fe n de r w ell b eh in d t h e a ir cleaner assembly. (Fig. 25).

REMOVAL

GLOW PLUG RELAY

(1 ) D is con n e ct t h e n e ga t i ve b a t t e r y ca b le a t t h e battery. (2) Loosen the 60–Way connector (Fig. 25). The electrical connector has a sliding bar which moves inward to lock or outward to unlock. (3 ) R em ov e t h e e le ct r i ca l con n e ct or b y p u ll in g straight out. (4) Remove P CM.

The glow plug relay is located in the engine compartment on the left–inner fender (Fig. 24).

INSTALLATION

(1) Apply high–temperatur e anti–seize compound to glow plug threads before installation (2 ) I n s t a ll t h e g low p lu g i n t o t h e cy li n de r h e a d . Tighten to 14 N·m (123 in. lbs.) torque. (3) Connect battery cable to battery.

(1 ) A ft e r t h e P C M e le ct r i ca l con n e ct or h a s b ee n separated from the PCM, inspect the pins for corro-

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Fig. 25 PCM Location 1 2 3 4

– – – –


Fig. 26 Vehicle Speed Sensor Location—4WD 1 – SENSOR ELECTRICAL CONNECTOR 2 – 4WD TRANSFER CASE EXTENSION 3 – VEHICLE SPEED SENSOR

s ion , b ei n g s p r ea d a p a r t , b en t or m i sa l ig n ed . A ls o i n sp e ct t h e p in h e ig h t s i n t h e con n e ct or . I f t h e p in h e ig h t s a r e d iffe r en t , t h i s w ou l d i n d i ca t e a p in h a s separated from the connector. Repair as necessary. (2 ) E n g a ge 6 0– wa y con n e ct or i n t o P C M . M ov e slide bar to lock connector. (3) Connect negative cable to battery.

VEHICLE SPEED SENSOR The vehicle speed sensor is located in the transfer case housing for 4 wheel drive vehicles (Fig. 26).

REMOVAL (1) Raise and support vehicle. (2) C lea n t h e a r ea a r ou n d t h e s en sor befor e removal. (3) Disconnect the electrical connector from the sensor (Fig. 27). (4) Remove the sensor mounting bolt (Fig. 27). (5 ) P u l l t h e s en s or fr om t h e s p ee d om e t er p in i on gear adapter for removal.

Fig. 27 Sensor Removal/Installation—Typical

INSTALLATION (1 ) I n st a ll n ew s en s or in t o s pe ed om et er ge ar adapter. (2) Tighten sensor mounting bolt. To prevent dama g e t o s e n sor or s p ee d om e t er a d a p t e r, b e s u r e t h e sensor is mounted flush to the adapter before tightening. (3) Conn ect electrical connector to sensor.

1 2 3 4 5 6 7

– – – – – – –

ELECTRICAL CONNECTOR SENSOR MOUNTING BOLT O-RING SPEEDOMETER PINION GEAR SPEEDOMETER PINION GEAR ADAPTER O-RING VEHICLE SPEED SENSOR

Jeep+2.5TD+Motor+VM

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