ignition system - home page for l. w. (bill) hughes iii

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GENERAL INFORMATIONINTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . 1

DESCRIPTION AND OPERATIONAUTOMATIC SHUTDOWN (ASD) RELAY . . . . . . 3CAMSHAFT POSITION SENSOR . . . . . . . . . . . . . 4CRANKSHAFT POSITION SENSOR . . . . . . . . . . . 3DISTRIBUTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 2ENGINE COOLANT TEMPERATURE SENSOR . . . 5IGNITION COIL . . . . . . . . . . . . . . . . . . . . . . . . . . 3IGNITION SWITCH AND KEY LOCKCYLINDER . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

IGNITION SYSTEM . . . . . . . . . . . . . . . . . . . . . . . 1INTAKE MANIFOLD AIR TEMPERATURESENSOR . . . . . . . . . . . . . . . . . . . .

. . . . . . . . .. 5

MANIFOLD ABSOLUTE PRESSURE (MAP)SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

POWERTRAIN CONTROL MODULE . . . . . . . . . . 2SPARK PLUG CABLES . . . . . . . . . . . . . . . . . . . . 3SPARK PLUGS . . . . . . . . . . . . . . . . . . . . . . . . . . 2THROTTLE POSITION SENSOR . . . . . . . . . . . . . 5

DIAGNOSIS AND TESTINGAUTOMATIC SHUTDOWN (ASD) RELAY TEST . 5CAMSHAFT POSITION SENSOR . . . . . . . . . . . . . 8CHECK COIL TEST . . . . . . . . . . . . . . . . . . . . . . . 6CRANKSHAFT POSITION SENSOR TEST . . . . . . 8DISTRIBUTOR CAP . . . . . . . . . . . . . . . . . . . . . . . 7DISTRIBUTOR ROTOR . . . . . . . . . . . . . . . . . . . . 8ENGINE COOLANT TEMPERATURE SENSOR . . 10FAILURE TO START TEST . . . . . . . . . . . . . . . . . 7IGNITION TIMING . . . . . . . . . . . . . . . . . . . . . . . . 8INTAKE MANIFOLD AIR TEMPERATURESENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

GENERAL INFORMATION

INTRODUCTIONThis group describes the ignition systems for both

the 2 .5L 4-cylinder and the 4.OL 6-cylinder engines.On Board Diagnostics is described in Group 25,

Emission Control Systems .Group 0, Lubrication and Maintenance, contains

general maintenance information (in time or mileage

IGNITION SYSTEM

CONTENTS

page

IGNITION SYSTEM

80- 1

page

MAP SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 8SPARK PLUG CABLES . . . . . . . . . . . . . . . . . . . 10SPARK PLUG CONDITIONS . . . . . . . . . . . . . . . 11TESTING FOR SPARK AT COIL . . . . . . . . . . . . . 5

REMOVAL AND INSTALLATIONAUTOMATIC SHUTDOWN (ASD) RELAY . . . . . 15CAMSHAFT POSITION SENSOR . . . . . . . . . . . . 16CRANKSHAFT POSITION SENSOR . . . . . . . . . . 15DISTRIBUTOR . . . . . . . . . . . . . . . . . . . . . . . . . . 17ENGINE COOLANT TEMPERATURE SENSOR . . 16IGNITION COIL . . . . . . . . . . . . . . . . . . . . . . . . . 14IGNITION SWITCH AND KEY CYLINDER . . . . . 20INTAKE MANIFOLD AIR TEMPERATURESENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

MANIFOLD ABSOLUTE PRESSURE (MAP)SENSOR . . . . . . . . . . . . . . . . . . . .

. .. . . . . . . 16

POWERTRAIN CONTROL MODULE (PCM) . . . 20SHIFTER/IGNITION INTERLOCK . . . . . . . . . . . . 22SPARK PLUG CABLES . . . . . . . . . . . . . . . . . . . 13SPARK PLUGS . . . . . . . . . . . . . . . . . . . . . . . . . 13THROTTLE POSITION SENSOR . . . . . . . . . . . . 17

SPECIFICATIONSENGINE FIRING ORDER-2 .5L 4-CYLINDERENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

ENGINE FIRING ORDER-4 .OL 6-CYLINDERENGINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

IGNITION COIL . . . . . . . . . . . . . . . . . . . . . . . . . 23IGNITION TIMING . . . . . . . . . . . . . . . . . . . . . . . 22SPARK PLUG CABLE RESISTANCE . . . . . . . . . 23SPARK PLUGS . . . . . . . . . . . . . . . . . . . . . . . . . 23TORQUE CHART . . . . . . . . . . . . . . . . . . . . . . . . 23VECI LABEL SPECIFICATIONS . . . . . . . . . . . . . 22

intervals) for ignition related items . The Owner'sManual also contains maintenance information .

DESCRIPTION AND OPERATION

IGNITION SYSTEMThe ignition systems used on the 2.5L 4-cylinder

and the 4.OL 6-cylinder engine are basically identi-cal . Similarities and differences between the systemswill be discussed .

80-2

IGNITION SYSTEM

DESCRIPTION AND OPERATION (Continued)

The ignition system is controlled by the powertraincontrol module (PCM) on all engines .The ignition system consists of" Spark Plugs" Ignition Coil" Secondary Ignition Cables" Distributor (contains rotor and camshaft position

sensor)" Powertrain Control Module (PCM)" Crankshaft Position, Camshaft Position, Throt-

tle Position and MAP Sensors

POWERTRAIN CONTROL MODULEThe Powertrain Control Module (PCM) is

in the engine compartment (Fig . 1) .

PCMMOUNTINGBOLTS (3)

(3) 32-WAYCONNECTOR

located

~NXI \N PONE RTRAINCONTROL MODULE

(PCM)

Fig. 1 Powertrain Control Module (PCM) LocationThe ignition system is controlled by the PCM.

NOTE:

Base ignition timing by rotation of distribu-tor Is not adjustable .

The PCM opens and closes the ignition coil groundcircuit to operate the ignition coil. This is done toadjust ignition timing, both initial (base) andadvance, and for changing engine operating condi-tions .The amount of electronic spark advance provided

by the PCM is determined by five input factors :engine coolant temperature, engine rpm, intake man-ifold temperature, manifold absolute pressure andthrottle position .

DISTRIBUTORAll 2.5L 4-cylinder and 4.OL 6-cylinder engines are

equipped with a camshaft driven mechanical distrib-utor containing a shaft driven distributor rotor.These distributors are equipped with an internalcamshaft position (fuel sync) sensor (Fig . 2) . Thissensor provides fuel injection synchronization andcylinder identification .

DISTRIBUTORASSEMBLY

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Fig. 2 Distributor and Camshaft Position Sensor(Typical Sensor Shown)

The distributors on 2.5L or 4.OL engines do nothave built in centrifugal or vacuum assisted advance .Base ignition timing and all, timing advance is con-trolled by the powertrain control module (PCM).Because ignition timing is controlled by the PCM,base ignition timing is not adjustable on any ofthese engines.The distributor is locked in place by a fork with a

slot located on the distributor housing base . The dis-tributor hold-down clamp bolt passes through thisslot when installed . Because the distributor positionis locked when installed, its rotational position cannot be changed . Do not attempt to modify the dis-tributor housing to get distributor rotation .Distributor position will have no effect on igni-tion timing. The position of the distributor willdetermine fuel synchronization only.

All distributors contain an internal oil seal thatprevents oil from entering the distributor housing .The seal is not serviceable .

SPARK PLUGSAll engines use resistor type spark plugs . Remove

the spark plugs and examine them for burned elec-trodes and fouled, cracked or broken porcelain insu-lators . Keep plugs arranged in the order in whichthey were removed from the engine. A single plugdisplaying an abnormal condition indicates that aproblem exists in the corresponding cylinder. Replace

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spark plugs at the intervals recommended in GroupO, Lubrication and MaintenanceSpark plugs that have low milage may be cleaned

and reused if not otherwise defective, carbon or oilfouled . Refer to the Spark Plug Condition section ofthis group .

SPARK PLUG CABLESSpark plug cables are sometimes referred to as sec-

ondary ignition wires . These cables transfer electricalcurrent from the ignition coil(s) and/or distributor, toindividual spark plugs at each cylinder. The resistivespark plug cables are of nonmetallic construction .The cables provide suppression of radio frequencyemissions from the ignition system .

IGNITION COILBattery voltage is supplied to the ignition coil pos-

itive terminal from the ASD relay.The Powertrain Control Module (PCM) opens and

closes the ignition coil ground circuit for ignition coiloperation .Base ignition timing is not adjustable on any

engine. By controlling the coil ground circuit, thePCM is able to set the base timing and adjust theignition timing advance . This is done to meet chang-ing engine operating conditions .The ignition coil is not oil filled . The windings are

embedded in an epoxy compound. This provides heatand vibration resistance that allows the ignition coilto be mounted on the engine .

AUTOMATIC SHUTDOWN (ASD) RELAYAs one of its functions, the ASD relay will supply

battery voltage to the ignition coil . The ground cir-cuit for the ASD relay is controlled by the PowertrainControl Module (PCM). The PCM regulates ASDrelay operation by switching the ground circuiton-and-off.

CRANKSHAFT POSITION SENSORThe crankshaft position sensor is mounted to the

transmission bellhousing at the left/rear side of theengine block (Fig . 3), (Fig . 4), or (Fig . 5) .Engine speed and crankshaft position are provided

through the crankshaft position sensor. The sensorgenerates pulses that are the input sent to the Pow-ertrain control module (PCM). The PCM interpretsthe sensor input to determine the crankshaft posi-tion . The PCM then uses this position, along withother inputs, to determine injector sequence and igni-tion timing .The sensor is a hall effect device combined with an

internal magnet . It is also sensitive to steel within acertain distance from it .

ELECTRICAL PIGTAILHARNESS

TRANSMISSIONBELLHOUSING

CONNECTOR

CRANKSHAFTPOSITIONSENSOR

IGNITION SYSTEM

80- 3

Fig. 3 Crankshaft Position Sensor-4.OL 6-Cyl.Engine-Auto. Trans.

ELECTRICAL CLAMP

TRANSMISSIONCONNECTOR

NUT \\BELLHOUSING

MOUNTINGSTUDS (2)


MOUNTINGNUTS (2)

80a43751

Fig . 4 Crankshaft Position Sensor-2.5L 4-Cyl.Engine-Auto. Trans.

SENSOR OPERATIONThe flywheel/drive plate has groups of four notches

at its outer edge . On 4.OL 6-cylinder engines thereare three sets of notches (Fig. 7) or (Fig. 8) . On 2 .5L4-cylinder engines there are two sets of notches (Fig .6) .The notches cause a pulse to be generated when

they pass under the sensor. The pulses are the input

8D - 4

IGNITION SYSTEM


TRANSMISSIONUELLHOUSING

ELECTRICAL CLAMPCONNECTOR NUT


Fig. 5 Crankshaft Position Sensor-ManualTransmission (Typical)

to the PCM. For each engine revolution there are twogroups of four pulses generated on 2.5L 4-cylinderengines . There are 3 groups of four pulses generatedon 4.OL 6-cylinder engines.The trailing edge of the fourth notch, which causes

the pulse, is four degrees before top dead center(TDC) of the corresponding piston .The engine will not operate if the PCM does not

receive a crankshaft position sensor input.


IV`MOUNTINGBOLTS (2) 80a43752

J928D-2

Fig. 6 Sensor Operation2.5L 4-Cyl. Engine



Fig . 7 Sensor Operation-4.0L 6-Cyl. EngineManual Transmission

J9314-84

Fig. 8 Sensor Operation-4.0L 6-Cyl. Engine-Automatic Transmission

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J958D-3

CAMSHAFT POSITION SENSORThe camshaft position sensor is located in the dis-

tributor on all engines (Fig . 2) .The sensor contains a hall effect device called a

sync signal generator to generate a fuel sync signal .This sync signal generator detects a rotating pulsering (shutter) on the distributor shaft. The pulse ringrotates 180 degrees through the sync signal genera-

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tor. Its signal is used in conjunction with the crank-shaft position sensor to differentiate between fuelinjection and spark events . It is also used to synchro-nize the fuel injectors with their respective cylinders .When the leading edge of the pulse ring (shutter)

enters the sync signal generator, the following occurs :The interruption of magnetic field causes the voltageto switch high resulting in a sync signal of approxi-mately 5 volts .When the trailing edge of the pulse ring (shutter)

leaves the sync signal generator, the following occurs :The change of the magnetic field causes the sync sig-nal voltage to switch low to 0 volts .

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSORFor an operational description, diagnosis and

removal/installation procedures, refer to Group 14,Fuel System .

ENGINE COOLANT TEMPERATURE SENSORFor an operational description, diagnosis and


THROTTLE POSITION SENSORFor an operational description, diagnosis and


INTAKE MANIFOLD AIR TEMPERATURE SENSORFor an operational description, diagnosis and


IGNITION SWITCH AND KEY LOCK CYLINDERThe ignition switch is located on the steering col-

umn. The Key-In-Switch is located in the ignitionswitch module . For electrical diagnosis of the Key-In-Switch, refer to Group 8U, Chime/Buzzer WarningSystems . For removal/installation of either the keylock cylinder or ignition switch, , refer to IgnitionSwitch and Key Cylinder in this group .On vehicles equipped with an automatic transmis-

sion, a cable connects an interlock device within thesteering column assembly to the transmission floorshift lever. This interlock device is used to lock thetransmission shifter in the PARK position when thekey is in the LOCKED or ACCESSORY position . Theinterlock device is not serviceable . If repair is neces-sary, the steering column assembly must be replaced.Refer to Group 19, Steering for procedures . Theshifter interlock cable can be adjusted or replaced.Refer to Group 21, Transmissions for procedures .On vehicles equipped with a manual transmission,

a lever is located on the steering column behind theignition key lock cylinder. The lever must be operated

DIAGNOSIS AND TESTING

TESTING FOR SPARK AT COIL

SPARK PLUGCABLE AND

BOOT

SPARK PLUG

IGNITION SYSTEM

80 - 5

to allow rotation of the ignition key lock cylinder. Thelever mechanism is not serviced separately. If repairis necessary, the steering column assembly must bereplaced . Refer to Group 19, Steering for procedures .

AUTOMATIC SHUTDOWN (ASO) RELAY TESTTo perform a complete test of this relay and its cir-

cuitry, refer to the DRB scan tool . Also refer to theappropriate Powertrain Diagnostics Procedures man-ual . To test the relay only, refer to Relays-Opera-tion/Testing in the Group 14, Fuel Systems section .

CAUTION: When disconnecting a high voltagecable from a spark plug or from the distributor cap,twist the rubber boot slightly (1/2 turn) to break itloose (Fig . 9) . Grasp the boot (not the cable) andpull it off with a steady, even force.

SPARK PLUG BOOTPULLER

Fig. 9 Cable Removal

958D-9

(1) Disconnect the ignition coil secondary cablefrom center tower of the distributor cap . Hold thecable terminal approximately 12 mm (1/2 in.) from agood engine ground (Fig. 10) .

WARNING: BE VERY CAREFUL WHEN THEENGINE IS CRANKING. DO NOT PUT YOUR HANDSNEAR THE PULLEYS, BELTS OR THE FAN. DO NOTWEAR LOOSE FITTING CLOTHING.

(2) Rotate (crank) the engine with the startermotor and observe the cable terminal for a steadyarc . If steady arcing does not occur, inspect the sec-ondary coil cable . Refer to Spark Plug Cables in thisgroup . Also inspect the distributor cap and rotor forcracks or burn marks. Repair as necessary. If steady

8D - 6

IGNITION SYSTEM

DIAGNOSIS AND TESTING (Continued)

Fig. 10 Checking for Spark-Typical

COIL (MANUFACTURER)

Diamond

Toyodenso

arcing occurs, connect ignition coil cable to the dis-tributor cap .

(3) Remove a cable from one spark plug .(4) Using insulated pliers, hold the cable terminal

approximately 12 mm (1/2 in.) from the engine cylin-der head or block while rotating the engine with thestarter motor. Observe the spark plug cable terminalfor an are . If steady arcing occurs, it can be expectedthat the ignition secondary system is operating cor-rectly. (If the ignition coil cable is removed forthis test, instead of a spark plug cable, thespark intensity will be much higher) . If steadyarcing occurs at the spark plug cables, but the enginewill not start, connect the DRB scan tool . Refer tothe appropriate Powertrain Diagnostic Proceduresservice manual .

CHECK COIL TESTTo perform a complete test of the ignition coil and

its circuitry, refer to the DRB scan tool . Also refer tothe appropriate Powertrain Diagnostics Proceduresmanual . To test the coil only, refer to the following :The ignition coil (Fig. 11) or (Fig . 12) is designed to

operate without an external ballast resistor .Inspect the ignition coil for arcing . Test the coil

according to coil tester manufacturer's instructions .Test the coil primary and secondary resistance .

PRIMARY RESISTANCE

21-27°C (70-80°F)

0.97 - 1 .18 Ohms

0.95 - 1 .20 Ohms

Fig. 13 Ignition Coil Resistance

Fig. 11 Ignition Coil-2.5L Engine

MOUNTINGBOLTS (2)

Fig. 12 Ignition Coil-4.0L Engine

Replace any coil that does not meet specifications .Refer to the Ignition Coil Resistance chart (Fig . 13) .

If the ignition coil is being replaced, the secondaryspark plug cable must also be checked. Replace cableif it has been burned or damaged.Arcing at the tower will carbonize the cable boot,

which if it is connected to a new ignition coil, willcause the coil to fail .

SECONDARY RESISTANCE

21-27°C (70-80°F)

11,300 - 15,300 Ohms

11,300 - 13,300 Ohms

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ELECTRICALCONNECTOR

ELECTRICALCONNECTOR

80a43753

J918D-2

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If the secondary coil cable shows any signs of dam-age, it should be replaced with a new cable and newterminal . Carbon tracking on the old cable can causearcing and the failure of a new ignition coil .

FAILURE TO START TESTTo prevent unnecessary diagnostic time and wrong

test results, the Testing For Spark At Coil testshould be performed prior to this test .

WARNING: SET PARKING BRAKE OR BLOCK THEDRIVE WHEELS BEFORE PROCEEDING WITH THISTEST

(1) Unplug the ignition coil electrical harness con-nector at the coil (Fig . 11) or (Fig. 12) .

(2) Connect a set of small jumper wires (18 gaugeor smaller) between the disconnected harness termi-nals and the ignition coil terminals . To determinepolarity at connector and coil, refer to Group 8WWiring Diagrams.

(3) Attach one lead of a voltmeter to the positive(12 volt) jumper wire. Attach the negative side ofvoltmeter to a good ground .

(4) Determine that sufficient battery voltage (12.4volts) is present for the starting and ignition sys-tems .

(5) Crank the engine for 5 seconds while monitor-ing the voltage at the coil positive terminal :

" If the voltage remains near zero during theentire period of cranking, refer to On-Board Diagnos-tics in Group 14, Fuel Systems . Check the Power-train Control Module (PCM) and auto shutdownrelay.

" If voltage is at or near battery voltage and dropsto zero after 1-2 seconds of cranking, check the pow-ertrain control module circuit . Refer to On-BoardDiagnostics in Group 14, Fuel Systems .

" If voltage remains at or near battery voltageduring the entire 5 seconds, turn the key off. Removethe three 32-way connectors (Fig . 14) from the PCM.Check 32-way connectors for any spread terminals orcorrosion .

(6) Remove test lead from the coil positive termi-nal . Connect an 18 gauge jumper wire between thebattery positive terminal and the coil positive termi-nal .

(7) Make the special jumper shown in (Fig . 15) .Using the jumper, momentarily ground the ignitioncoil driver circuit at the PCM connector (cavity A-7) .For cavity/terminal location of this circuit, refer toGroup 8W Wiring. A spark should be generated atthe coil cable when the ground is removed .

(8) If spark is generated, replace the PCM.(9) If spark is not seen, use the special jumper to

ground the coil negative terminal directly.

PCMMOUNTING80LTS (3)

(3) 32-WAYCONNECTOR\

Fig. 14 PCM and Three 32-Way Connectors

ALLIGATOR CLIP

IGNITION SYSTEM

8D - 7

\

WERTRRANCONTROL MODULE

(PCM) f~

CONNECT THIS-CLIP TO COILNEGATIVE ALLIGATOR

CLIPMOMENTARILYGROUND THISCLIP TO COILNEGATIVE

RB1003

Fig. 15 Special Jumper Ground-to-Coil NegativeTerminal

(10) If spark is produced, repair wiring harness foran open condition .

(11) If spark is not produced, replace the ignitioncoil .

DISTRIBUTOR CAPRemove the distributor cap and wipe it clean with

a dry lint free cloth . Visually inspect the cap forcracks, carbon paths, broken towers or damagedrotor button (Fig . 16) or (Fig. 17) . Also check forwhite deposits on the inside (caused by condensationentering the cap through cracks) . Replace any capthat displays charred or eroded terminals. Themachined surface of a terminal end (faces towardrotor) will indicate some evidence of erosion fromnormal operation . Examine the terminal ends for evi-dence of mechanical interference with the rotor tip .

80 - 8

IGNITION SYSTEM


Fig . 16 Cap Inspection-External-Typical

Fig. 17 Cap Inspection-Internal-Typical

IGNITION TIMING

DISTRIBUTOR ROTORVisually inspect the rotor (Fig . 18) for cracks, evi-

dence of corrosion or the effects of arcing on themetal tip . Also check for evidence of mechanicalinterference with the cap . Some charring is normalon the end of the metal tip . The silicone-dielectric-varnish-compound applied to the rotor tip for radiointerference noise suppression, will appear charred.This is normal . Do not remove the charred com-pound. Test the spring for insufficient tension .Replace a rotor that displays any of these adverseconditions .

NOTE: Base (initial) ignition timing is NOT adjust-able on any 2.5L 4-cylinder or 4.OL 6-cylinderengine . Do not attempt to adjust ignition timing byrotating the distributor.

INSUFFICIENTSPRINGTENSION

ROTORTIP

CORRODED

EVIDENCE OFPHYSICALCONTACTWITH CAP

J908D-48

Fig . 18 Rotor Inspection-Typical

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NOTE: Do not attempt to modify the distributorhousing to get distributor rotation . Distributor posi-tion will have no effect on ignition timing .

All ignition timing functions are controlled by thepowertrain control module (PCM). For additionalinformation, refer to the appropriate PowertrainDiagnostics Procedures service manual for operationof the DRB Scan Tool .

MAP SENSORFor an operational description, diagnosis or remov-

al/ installation procedures, refer to Group 14, FuelSystems .

CRANKSHAFT POSITION SENSOR TESTTo perform a complete test of this sensor and its

circuitry, refer to the DRB scan tool. Also refer to theappropriate Powertrain Diagnostics Procedures man-ual . To test the sensor only, refer to the following :The crankshaft position sensor is mounted to the

transmission bellhousing at the left/rear side of theengine block (Fig. 19), (Fig . 20), or (Fig . 21) .

(1) Near the rear of the intake manifold, discon-nect sensor pigtail harness connector from main wir-ing harness (Fig . 19), (Fig . 20), or (Fig . 21) .

(2) Place an ohmmeter across terminals B and C(Fig. 22) . Ohmmeter should be set to 1K-to-10K scalefor this test. The meter reading should be open (highresistance) . Replace sensor if a low resistance is indi-cated.


tributor (Fig. 23) on all engines .

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ELECTRICAL PIGTAILHARNESS


CONNECTOR



ELECTRICAL CLAMP


NUT \\BELLHOUSING

MOUNTINGSTUDS (2)


MOUNTINGNUTS (2)

80 .43751

Fig. 20 Crankshaft Position Sensor-2.5L 4-Cyl.Engine-Auto. Trans.

To perform a complete test of this sensor and itscircuitry, refer to the appropriate Powertrain Diag-nostics Procedures service manual . To test the sensoronly, refer to the following :For this test, an analog (non-digital) voltme-

ter is needed. Do not remove the distributor connec-tor from the distributor. Using small paper clips,insert them into the backside of the distributor wire

ELECTRICAL CLAMP


NUT \\BELLHOUSING


IGNITION SYSTEM

8D - 9

I mo 'MOUNTINGBOLTS (2)


f f P

VIEW LOOKING INTO SENSORPIGTAIL ELECTRICAL CONNECTOR

80.43752

Fig. 22 Crankshaft Position Sensor Connector

80.43754

harness connector to make contact with the termi-nals . Be sure that the connector is not damagedwhen inserting the paper clips . Attach voltmeterleads to these paper clips .

(1) Connect the positive (+) voltmeter lead into thesensor output wire . This is at done the distributorwire harness connector. For wire identification, referto Group 8W Wiring Diagrams .

(2) Connect the negative (-) voltmeter lead into theground wire . For wire identification, refer to Group8W Wiring Diagrams .

(3) Set the voltmeter to the 15 Volt DC scale .(4) Remove distributor cap from distributor (two

screws) . Rotate (crank) the engine until the distribu-tor rotor is approximately in the 11 o'clock position .

8D - 1 0

IGNITION SYSTEM


DISTRIBUTORASSEMBLY

Fig. 23 Camshaft Position Sensor-Typical

The movable pulse ring should now be within thesensor pickup .

(5) Turn ignition key to ON position . Voltmetershould read approximately 5.0 volts.

(6) If voltage is not present, check the voltmeterleads for a good connection .

(7) If voltage is still not present, check for voltageat the supply wire . For wire identification, refer toGroup 8W Wiring Diagrams .

(8) If 5 volts is not present at supply wire, checkfor voltage at PCM 32-way connector (cavity A-17).Refer to Group 8W Wiring for location of connector/terminal . Leave the PCM connector connected forthis test .

(9) If voltage is still not present, perform vehicletest using the DRB scan tool .

(10) If voltage is present at cavity A-17, but not atthe supply wire :

(a) Check continuity between the supply wire .This is checked between the distributor connectorand cavity A-17 at the PCM. If continuity is notpresent, repair the harness as necessary.

(b) Check for continuity between the camshaftposition sensor output wire and cavity A-18 at, thePCM. If continuity is not present, repair the har-ness as necessary.

(c) Check for continuity between the ground cir-cuit wire at the distributor connector and ground .If continuity is not present, repair the harness asnecessary.(11) While observing the voltmeter, crank the

engine with ignition switch . The voltmeter needleshould fluctuate between 0 and 5 volts while theengine is cranking. This verifies that the camshaftposition sensor in the distributor is operating prop-erly and a sync pulse signal is being generated.

If sync pulse signal is not present, replacement ofthe camshaft position sensor is necessary

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removal/installation procedures, refer to Group 14,Fuel System.


removal/installation procedures, refer to Group 14,Fuel System.

SPARK PLUG CABLESCheck the spark plug cable connections for good

contact at the coil(s), distributor cap towers, andspark plugs. Terminals should be fully seated . Theinsulators should be in good condition and should fittightly on the coil, distributor and spark plugs. Sparkplug cables with insulators that are cracked or tornmust be replaced .Clean high voltage ignition cables with a cloth

moistened with a non-flammable solvent. Wipe thecables dry. Check for brittle or cracked insulation .

TESTINGWhen testing secondary cables for damage with an

oscilloscope, follow the instructions of the equipmentmanufacturer.

If an oscilloscope is not available, spark plug cablesmay be tested as follows:

CAUTION:

Do not leave any one spark plug cable dis-connected for longer than necessary during testing .This may cause possible heat damage to the catalyticconverter . Total test time must not exceed ten minutes .With the engine running, remove spark plug cable

from spark plug (one at a time) and hold next to agood engine ground . If the cable and spark plug arein good condition, the engine rpm should drop andthe engine will run poorly. If engine rpm does notdrop, the cable and/or spark plug may not be operat-ing properly and should be replaced . Also checkengine cylinder compression.With the engine not running, connect one end of a

test probe to a good ground . Start the engine and runthe other end of the test probe along the entire length ofall spark plug cables . If cables are cracked or punc-tured, there will be a noticeable spark jump from thedamaged area to the test probe. The cable running fromthe ignition coil to the distributor cap can be checked inthe same manner. Cracked, damaged or faulty cablesshould be replaced with resistance type cable. This canbe identified by the words ELECTRONIC SUPPRES-SION printed on the cable jacket .Use an ohmmeter to test for open circuits, excessive

resistance or loose terminals. Remove the distributorcap from the distributor. Do not remove cables fromcap. Remove cable from spark plug. Connect ohmme-ter to spark plug terminal end of cable and to corre-

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sponding electrode in distributor cap. Resistanceshould be 250 to 1000 Ohms per inch of cable. If not,remove cable from distributor cap tower and connectohmmeter to the terminal ends of cable. If resistanceis not within specifications as found in the SparkPlug Cable Resistance chart, replace the cable. Testall spark plug cables in this manner.

MINIMUM I MAXIMUM250 Ohms Per Inch

1

1000 Ohms Per Inch3000 Ohms Per Foot

1

12,000 Ohms Per Foot

SPARK PLUG CABLE RESISTANCE

To test ignition coil-to-distributor cap cable, do notremove the cable from the cap. Connect ohmmeter torotor button (center contact) of distributor cap andterminal at ignition coil end of cable. If resistance isnot within specifications as found in the Spark PlugCable Resistance chart, remove the cable from thedistributor cap. Connect the ohmmeter to the termi-nal ends of the cable. If resistance is not within spec-ifications as found in the Spark Plug CableResistance chart, replace the cable. Inspect the igni-tion coil tower for cracks, burns or corrosion.

SPARK PLUG CONDITIONS

J908D-43

NORMAL OPERATINGThe few deposits present on the spark plug will

probably be light tan or slightly gray in color. This isevident with most grades of commercial gasoline(Fig. 24). There will not be evidence of electrodeburning. Gap growth will not average more thanapproximately 0.025 mm (.001 in) per 1600 km (1000miles) of operation . Spark plugs that have normalwear can usually be cleaned, have the electrodesfiled, have the gap set and then be installed.

NORMAL

DRY BLACK

COLD (CARBON) FOULINGDEPOSITS

J908D-15Fig. 24 Normal Operation and Cold (Carbon) Fouling

IGNITION SYSTEM

8D - 1 1

Some fuel refiners in several areas of the UnitedStates have introduced a manganese additive (MMT)for unleaded fuel . During combustion, fuel with MMTcauses the entire tip of the spark plug to be coatedwith a rust colored deposit . This rust color can bemisdiagnosed as being caused by coolant in the com-bustion chamber. Spark plug performance is notaffected by MMT deposits .

COLD FOULING/CARBON FOULINGCold fouling is sometimes referred to as carbon

fouling. The deposits that cause cold fouling are basi-cally carbon (Fig . 24). A dry, black deposit on one ortwo plugs in a set may be caused by sticking valvesor defective spark plug cables . Cold (carbon) foulingof the entire set of spark plugs may be caused by aclogged air cleaner element or repeated short operat-ing times (short trips) .

WET FOULING OR GAS FOULINGA spark plug coated with excessive wet fuel or oil

is wet fouled . In older engines, worn piston rings,leaking valve guide seals or excessive cylinder wearcan cause wet fouling. In new or recently overhauledengines, wet fouling may occur before break-in (nor-mal oil control) is achieved . This condition can usu-ally be resolved by cleaning and reinstalling thefouled plugs .

OIL OR ASHENCRUSTEDIf one or more spark plugs are oil or oil ash encrusted

(Fig. 25), evaluate engine condition for the cause of oilentry into that particular combustion chamber.

Fig. 25 Oil or Ash Encrusted

8D - 12

IGNITION SYSTEM


ELECTRODE GAP BRIDGINGElectrode gap bridging may be traced to loose depos-

its in the combustion chamber. These deposits accumu-late on the spark plugs during continuous stop-and-godriving. When the engine is suddenly subjected to ahigh torque load, deposits partially liquefy and bridgethe gap between electrodes (Fig. 26). This short circuitsthe electrodes . Spark plugs with electrode gap bridgingcan be cleaned using standard procedures .

GROUNDELECTRODE

SCAVENGER DEPOSITSFuel scavenger deposits may be either white or yellow

(Fig . 27). They may appear to be harmful, but this is anormal condition caused by chemical additives in cer-tain fuels . These additives are designed to change thechemical nature of deposits and decrease spark plugmisfire tendencies . Notice that accumulation on theground electrode and shell area may be heavy, but thedeposits are easily removed. Spark plugs with scavengerdeposits can be considered normal in condition and canbe cleaned using standard procedures .

Fig. 26 Electrode Gap Bridging

Fig. 27 Scavenger Deposits

J908D-11

GROUNDELECTRODECOVEREDWITH WHITEOR YELLOWDEPOSITS

J908D-12

CHIPPED ELECTRODE INSULATORA chipped electrode insulator usually results from

bending the center electrode while adjusting thespark plug electrode gap. Under certain conditions,severe detonation can also separate the insulatorfrom the center electrode (Fig . 28). Spark plugs withthis condition must be replaced .GROUNDELECTRODE

GROUNDELECTRODESTARTING

TO DISSOLVE

J908D-13Fig. 28 Chipped Electrode Insulator

PREIGNITION DAMAGEPreignition damage is usually caused by excessive com-

bustion chamber temperature. The center electrode dis-solves first and the ground electrode dissolves somewhatlatter (Fig . 29). Insulators appear relatively deposit free .Determine if the spark plug has the correct heat rangerating for the engine . Determine if ignition timing is overadvanced or if other operating conditions are causingengine overheating. (The heat range rating refers to theoperating temperature of a particular type spark plug.Spark plugs are designed to operate within specific tem-perature ranges . This depends upon the thickness andlength of the center electrodes porcelain insulator.)

Fig. 29 Preignition Damage

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CENTERELECTRODEDISSOLVED

J908D-14

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SPARK PLUG OVERHEATINGOverheating is indicated by a white or gray center

electrode insulator that also appears blistered (Fig.30). The increase in electrode gap will be consider-ably in excess of 0 .001 inch per 1000 miles of opera-tion . This suggests that a plug with a cooler heatrange rating should be used . Over advanced ignitiontiming, detonation and cooling system malfunctionscan also cause spark plug overheating.

Fig. 30 Spark Plug Overheating

REMOVAL AND INSTALLATION

SPARK PLUG CABLES

SPARK PLUGCABLE AND

BOOT

SPARK PLUG

SPARK PLUG BOOTPULLER

Fig. 31 Cable Removal

J908D-16

CAUTION: When disconnecting a high voltagecable from a spark plug or from the distributor cap,twist the rubber boot slightly (1/2 turn) to break itloose (Fig . 31) . Grasp the boot (not the cable) andpull it off with a steady, even force.

958D-9

Install cables into the proper engine cylinder firingorder (Fig . 32) or (Fig. 33).

FIRING ORDER :1 3 4 2CLOCKWISEROTATION

FIRING ORDER :1 5 3 6 2 4CLOCKWISEROTATION

SPARK PLUGS

IGNITION SYSTEM

80- 13

Fig. 32 Engine Firing Order-2.5L 4-Cylinder Engine

FRONT

JO!JC

J908D-6

J908D-7

Fig. 33 Engine Firing Order-4.OL 6-Cylinder Engine

When replacing the spark plug and coil cables,route the cables correctly and secure in the properretainers. Failure to route the cables properly cancause the radio to reproduce ignition noise. It couldalso cause cross ignition of the plugs or short circuitthe cables to ground .When installing new cables, make sure a positive

connection is made . A snap should be felt when agood connection is made between the plug cable andthe distributor cap tower.

PLUG REMOVAL(1) Always remove spark plug or ignition coil

cables by grasping at the cable boot (Fig . 31). Turnthe cable boot 1/2 turn and pull straight back in asteady motion. Never pull directly on the cable .Internal damage to cable will result .

80-14

IGNITION SYSTEM

REMOVAL AND INSTALLATION (Continued)

(2) Prior to removing the spark plug, spray com-pressed air around the spark plug hole and the areaaround the spark plug . This will help prevent foreignmaterial from entering the combustion chamber.

(3) Remove the spark plug using a quality socketwith a rubber or foam insert .

(4) Inspect the spark plug condition . Refer toSpark Plugs in the Diagnostics/Service Proceduressection of this group .

PLUG CLEANINGThe plugs may be cleaned using commercially

available spark plug cleaning equipment . After clean-ing, file the center electrode flat with a small pointfile or jewelers file before adjusting gap .

CAUTION:

Never use a motorized wire wheel brushto clean the spark plugs. Metallic deposits willremain on the spark plug insulator and will causeplug misfire.

PLUG GAPADJUSTMENTCheck the spark plug gap with a gap gauge tool . If

the gap is not correct, adjust it by bending theground electrode (Fig . 34) . Never attempt to adjustthe gap by bending the center electrode.

J90OD-10

Fig. 34 Setting Spark Plug Gap-TypicalSPARK PLUG GAP

" 2.5L 4-Cylinder Engine Spark Plug Gap: .89 mm(.035 in) .

" 4.OL 6-Cylinder Engine Spark Plug Gap: .89 mm(.035 in) .

IGNITION COIL

Fig. 35 Ignition Coil2.5L Engine

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PLUG INSTALLATIONAlways tighten spark plugs to the specified torque .

Over tightening can cause distortion . This may resultin a change in the spark plug gap, or a cracked por-celain insulator.When replacing the spark plug and ignition coil

cables, route the cables correctly and secure them inthe appropriate retainers . Failure to route the cablesproperly can cause the radio to reproduce ignitionnoise . It could cause cross ignition of the spark plugs,or short circuit the cables to ground .

(1) Start the spark plug into the cylinder head byhand to avoid cross threading .

(2) Tighten the spark plugs to 35-41 N-m (26-30 ft .lbs .) torque .

(3) Install spark plug cables over spark plugs.

The ignition coil is an epoxy filled type . If the coilis replaced, it must be replaced with the same type.

REMOVALOn the 2.5L 4-cylinder engine, the ignition coil is

mounted to a bracket on the side of the engine (tothe rear of the distributor) (Fig. 35) .On the 4.OL 6-cylinder engine, the ignition coil is

mounted to a bracket on the side of the engine (tothe front of the distributor) (Fig . 36) .

ELECTRICALCONNECTOR

(1) Disconnect the ignition coil secondary cablefrom ignition coil .

(2) Disconnect engine harness connector from igni-tion coil .

(3) Remove ignition coil mounting bolts (nuts areused on back side of bracket on some coils) .

(4) Remove coil from vehicle .

INSTALLATION(1) Install ignition coil to bracket on cylinder block

with mounting bolts (and nuts if equipped) . If

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MOUNTINGBOLTS (2)

Fig. 36 Ignition Coil-4.OL Engine

Fig. 37 PDC Location

REMOVAL(1) Remove the PDC cover.(2) Remove the relay by lifting straight up.

ELECTRICALCONNECTOR

80a43753

equipped with nuts and bolts, tighten to 11 N-m (100in . lbs .) torque . If equipped with bolts only, tighten to5 N-m (50 in . lbs .) torque.

(2) Connect engine harness connector to coil .(3) Connect ignition coil cable to ignition coil .

AUTOMATIC SHUTDOWN (ASD) RELAYThe ASD relay is located in the Power Distribution

Center (PDC) (Fig. 37) . Relay location is printed on alabel on PDC cover.

wwwPOWER DISTRIBUTION

CENTER jr-DC)

80a43755

INSTALLATION(1) Check condition of relay terminals at PDC for

corrosion or damage. Also check the heights of relayterminal pins at PDC . Pin height should be same forall pins. Repair as necessary before installing relay.

(2) Push the relay into the connector.(3) Install the relay cover.

CRANKSHAFT POSITION SENSORThe crankshaft position sensor is mounted to the

transmission bellhousing at the left/rear side of theengine block (Fig. 38), (Fig. 39), or (Fig . 40) .On 2.5L 4-cylinder and 4.OL 6-cylinder engines

equipped with a manual transmission, the sensor isattached with two bolts . On 2.5L engines equippedwith an automatic transmission, the sensor isattached with two nuts . On 4.OL engines equippedwith an automatic transmission, the sensor isattached with one bolt .

ELECTRICALCONNECTOR


IGNITION SYSTEM

8D - 1 5

PIGTAILHARNESS



REMOVAL(1) Near the rear of the intake manifold, discon-

nect the pigtail harness (electrical connector) fromthe main electrical harness .

(2) Remove the nut holding sensor harness wireclip to fuel rail mounting stud .

(3) Depending upon application, remove either thesensor mounting bolt(s) or nuts .

(4) Remove the sensor.(5) Remove clip from sensor wire harness .

INSTALLATION(1) Install the sensor flush against the opening in

the transmission housing .(2) 2 .5L and 4.OL engines equipped with a manual

transmission : Install and tighten the two sensormounting bolts to 19 N-m (14 ft . lbs .) torque . Thetwo sensor mounting bolts are speciallymachined to correctly space the unit to the fly-wheel. Do not attempt to install any other bolts.

8D - 1 6

IGNITION SYSTEM


ELECTRICAL CLAMP


NUT \\BELLHOUSING

MOUNTINGSTUDS (2)



MOUNTINGNUTS (2)


8Oa43751

Fig. 39 Crankshaft Position Sensor-2.5L 4-Cyl.'Engine-Auto. Trans.

ELECTRICAL CLAMP--, --,_ ..TRANSMISSIONCONNECTOR NUT

80a43752

(3) 2.5L engines equipped with an automatictransmission : Install and tighten the two sensormounting nuts to 19 N-m (14 ft . lbs .) torque .

(4) 4.OL engines equipped with an automatictransmission : Install and tighten the sensor mount-ing bolt to 7 N-m (60 in . lbs .) torque .

(5) Connect the sensor pigtail harness electricalconnector to main wiring harness .

(6) Install clip on sensor wire harness .(7) Install clip over fuel rail mounting stud.(8) Install clip mounting nut.

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tributor (Fig. 41) .

REMOVALDistributor removal is not necessary to remove

camshaft position sensor.(1) Disconnect negative battery cable at battery.(2) Remove distributor cap from distributor (two

screws) .(3) Disconnect camshaft position sensor wiring

harness from main engine wiring harness .

DISTRIBUTORASSEMBLY

Fig. 41 Camshaft Position Sensor

(4) Remove distributor rotor from distributor shaft .(5) Lift the camshaft position sensor assembly

from the distributor housing (Fig . 41) .

INSTALLATION(1) Install camshaft position sensor to distributor.

Align sensor into notch on distributor housing .(2) Connect wiring harness .(3) Install rotor.(4) Install distributor cap . Tighten mounting

screws .

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSORFor removal and installation, refer to Manifold

Absolute Pressure Sensor in group 14, Fuel Systems .



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THROTTLE POSITION SENSORFor an operational description, diagnosis and




DISTRIBUTORAll distributors contain an internal oil seal that

prevents oil from entering the distributor housing .The seal is not serviceable .Factory replacement distributors are equipped with

a plastic alignment pin already installed . The pin islocated in an access hole on the bottom of the distrib-utor housing (Fig . 42) . It is used to temporarily lockthe rotor to the cylinder number 1 position duringinstallation . The pin must be removed after install-ing the distributor .

Fig. 42 Plastic Alignment Pin

The camshaft position sensor is located in the dis-tributor on all engines (Fig . 43) . For removal/instal-lation procedures, refer to Camshaft Position Sensor.Distributor removal is not necessary for sensorremoval .Refer to (Fig. 43) for an exploded view of the dis-

tributor .A fork with a slot is supplied on the bottom of the

distributor housing where the housing base seatsagainst the engine block (Fig . 43) . The centerline ofthe slot aligns with the distributor hold-down bolt

IGNITION SYSTEM

8D - 1 7

CAP

CAMSHAFT POSITIONSENSOR

WASHER-

Fig. 43 Distributor-2.5L Or 4.OL Engines-Typical

hole in the engine block . Because of the fork, the dis-tributor cannot be rotated . Distributor rotation is notnecessary as all ignition timing requirements arehandled by the powertrain control module (PCM).The position of the distributor determines fuel syn-

chronization only. It does not determine ignition tim-ing.

NOTE: Do not attempt to modify this fork to attainignition timing .

REMOVAL-2.51. OR 4.OL ENGINE(1) Disconnect the negative battery cable at the

battery.(2) Disconnect coil secondary cable at coil .(3) Remove distributor cap from distributor (2

screws). Do not remove cables from cap . Do notremove rotor.

(4) Disconnect the distributor wiring harness fromthe main engine harness .

(5) Remove the cylinder number 1 spark plug.(6) Hold a finger over the open spark plug hole .

Rotate the engine at the vibration dampener boltuntil compression (pressure) is felt .

(7) Slowly continue to rotate the engine . Do thisuntil the timing index mark on the vibration damper

8D - 1 8

IGNITION SYSTEM


pulley aligns with the top dead center (TDC) mark (0degree) on timing degree scale (Fig. 44) . Alwaysrotate the engine in direction of normal rotation . Donot rotate the engine backward to align the timingmarks.

CRANKSHAFTVIBRATION DAMPERTIMING MARK

Fig. 44 Align Timing Marks

J898D-14

(8) Remove the distributor hold-down bolt andclamp .

(9) Remove the distributor fromlifting straight up .

(10) Note that the rotor will rotate slightly in acounterclockwise direction while lifting up the dis-tributor. The oil pump gear will also rotate slightly ina counterclockwise direction while lifting up the dis-tributor. This is due to the helical cut gears on thedistributor and camshaft.

(11) Note the removed position of the rotor duringdistributor removal . During installation, this will bereferred to as the Pre-position .

(12) 2.5L 4-Cylinder Engine: Observe the slot inthe oil pump gear through the hole on the side of theengine. It should be slightly before (counterclockwiseof) the 10 o'clock position (Fig . 45) .

(13) 4.OL 6-Cylinder Engine: Observe the slot inthe oil pump gear through the hole on the side of theengine . It should be slightly before (counterclockwiseof) the 11 o'clock position (Fig . 46).(14) Remove and discard the old distributor-to-en-

gine block gasket .

engine by slowly

INSTALLATION(1) If the engine crankshaft has been rotated after

distributor removal, cylinder number 1 must bereturned to its proper firing stroke . Refer to previous

10 O'CLOCK POSITION

FRONT

OILPUMPSLOT J958D-6

Fig. 45 Slot At 10 O'clock Position-2.5L Engine

11 O'CLOCK POSITION

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FRONT

OILPUMPSLOT J958D-7

Fig. 46 Slot At 11 O'clock Position-4.0L Engine

REMOVAL Step 5 and Step 6 . These steps must bedone before installing distributor.

(2) Check the position of the slot on the oil pumpgear. On the 2.5L engine, it should be just slightlybefore (counterclockwise of) the 10 o'clock position(Fig . 45) . On the 4.OL engine, it should be justslightly before (counterclockwise of) the 11 o'clockposition (Fig. 46) . If not, place a flat blade screw-driver into the oil pump gear and rotate it into theproper position.

(3) Factory replacement distributors are equippedwith a plastic alignment pin already installed (Fig .42) . This pin is used to temporarily hold the rotor tothe cylinder number 1 firing position during distrib-utor installation . If this pin is in place, proceed toStep 8 . If not, proceed to next step .

(4) If the original distributor is to be reinstalled,such as during engine overhaul, the plastic pin willnot be available . A 3/16 inch drift pin punch tool maybe substituted for the plastic pin.

(5) Remove the camshaft position sensor from thedistributor housing. Lift straight up .

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(6) Four different alignment holes are provided onthe plastic ring (Fig . 47) . Note that 2.5L and 4.OLengines have different alignment holes (Fig.47) .

(7) Rotate the distributor shaft and install the pinpunch tool through the proper alignment hole in theplastic ring (Fig . 47) and into the mating access holein the distributor housing. This will prevent the dis-tributor shaft and rotor from rotating.

DISTRIBUTOR PULSEHOUSING RING(TOP VIEW)

4.01.6-CYLINDERENGINE

ALIGN. HOLE

2.5 L4-CYLINDERENGINE

ALIGN . HOLE

MATING ACCESS HOLEIN DISTRIBUTOR HOUSING

J958D-5

Fig. 47 Pin Alignment Holes

(8) Clean the distributor mounting hole area of theengine block .

(9) Install a new distributor-to-engine block gasket(Fig. 43) .

(10) Install the rotor to the distributor shaft .(11) 2.5L 4-Cylinder Engine: Pre-position the

distributor into the engine while holding the center-line of the base slot in the 1 o'clock position (Fig . 48) .Continue to engage the distributor into the engine .The rotor and distributor will rotate clockwise duringinstallation . This is due to the helical cut gears onthe distributor and camshaft. When the distributor isfully seated to the engine block, the centerline of thebase slot should be aligned to the clamp bolt mount-ing hole on the engine (Fig . 49) . The rotor shouldalso be pointed slightly past (clockwise of) the 3o'clock position .4.OL 6-Cylinder Engine: Pre-position the distrib-

utor into the engine while holding the centerline ofthe base slot in the 1 o'clock position (Fig . 48) . Con-tinue to engage the distributor into the engine . Therotor and distributor will rotate clockwise duringinstallation . This is due to the helical cut gears onthe distributor and camshaft . When the distributor is

fully seated to the engine block, the centerline of thebase slot should be aligned to the clamp bolt mount-ing hole on the engine (Fig . 50) . The rotor shouldalso be pointed at the 5 o'clock position .

It may be necessary to rotate the rotor and distrib-utor shaft (very slightly) to engage the distributorshaft with the slot in the oil pump gear. The samemay have to be done to engage the distributor gearwith the camshaft gear .

Fig. 48 Distributor Pre-position-All Engines

IGNITION SYSTEM

8D - 1 9

1 O'CLOCK

FRONTPOSITION

DISTRIBUTORBASE

J958D-8

FRONT

CLAMPBOLT MOUNTING

HOLE(ON ENGINE)

Fig. 49 Distributor Engaged Position2.5L4-Cylinder Engine

J958D-9

80 - 20

IGNITION SYSTEM


DISTRIBUTORBASESLOT

6-Cylinder Engine

CLAMP BOLTMOUNTING

HOLE(ON ENGINE)

FRONT

Fig. 50 Distributor Engaged Position-4.0L

J958D-10

The distributor is correctly installed when:" the rotor is pointed at the 3 o'clock position

(2.5L engine), or at the 5 o'clock position (4.OLengine) .

" the plastic alignment pin (or pin punch tool) isstill installed to distributor.

" the number 1 cylinder piston is set at top deadcenter (TDC) (compression stroke) .

" the centerline of the slot at the base of the dis-tributor is aligned to the centerline of the distributorhold-down bolt hole on the engine . In this position,the hold-down bolt should easily pass through theslot and into the engine .No adjustments are necessary. Proceed to next

step .(12) Install the distributor hold-down clamp and

bolt . Tighten the bolt to 23 N-m (17 ft . lbs .) torque .(13) Remove the pin punch tool from the distribu-

tor. Or, if the plastic alignment pin was used, removeit straight down from the bottom of the distributor.Discard plastic pin .(14) If removed, install the camshaft position sen-

sor to the distributor. Align the wiring harness grom-met to the notch in the distributor housing .

(15) Install the rotor.

CAUTION:

If the distributor cap is incorrectly posi-tioned on distributor housing, the cap or rotor maybe damaged when engine is started.

(16) Install the distributor cap . Tighten distributorcap hold-down screws to 3 N-m (26 in . lbs .) torque .

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(17) If removed, install the spark plug cables tothe distributor cap. For proper firing order, refer tothe Specifications section at the end of this group.See Engine Firing Order.

(18) Connect the distributor wiring harness to themain engine harness .

(19) Connect battery cable to battery.

POWERTRAIN CONTROL MODULE (PCM)Refer to Group 14, Fuel System for procedures .

IGNITION SWITCH AND KEY CYLINDERThe ignition key must be in the key cylinder for

cylinder removal . The key cylinder must be removedfirst before removing ignition switch .

KEYCYLINDER REMOVAL(1) Disconnect negative battery cable at battery.(2) If equipped with an automatic transmission,

place shifter in PARK position .(3) Rotate key to ON position .(4) A release tang is located on bottom of key cyl-

inder (Fig . 51) .

KEY CYLINDER

RELEASE TANG

Fig. 51 Key Cylinder Release Tang

80a43756

(5) Position a small screwdriver or pin punch intotang access hole on bottom of steering column lowercover (Fig . 52) .

(6) Push the pin punch up while pulling key cylin-der from steering column .

IGNITION SWITCH REMOVAL(1) Remove key cylinder . Refer to previous steps .(2) Remove lower steering column cover screws

and remove cover (Fig . 52).(3) Disconnect two electrical connectors at rear of

ignition switch (Fig . 53) .(4) Remove ignition switch mounting screw (Fig .

53) . Use tamper proof torx bit (Snap-On® SDMTR10or equivalent) to remove the screw.

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ELECTRICALCONNECTORS

Fig. 52 Key Cylinder and Cover Removal

Fig. 53 Ignition Switch Removal/Installation

IGNITIONSWITCH=

80a43758

(5) Using a small screwdriver, push on locking tab(Fig . 54) and remove switch from steering column.

IGNITION SWITCH INSTALLATION(1) Before installing ignition switch, rotate the slot

in the switch to the ON position (Fig . 55) .(2) Position switch to column and install tamper

proof screw. Tighten screw to 3 N-m (26 in . lbs .) .

ROTATE TOON POSITION

IGNITION SYSTEM

8D - 21

Fig. 54 Ignition Switch Lock Tab

IGNITION SWITCH

Fig. 55 Switch In ON Position

80a43850

(3) Connect two electrical connectors to rear ofignition switch . Make sure that locking tabs are fullyseated into wiring connectors .

(4) Install steering column lower cover.

KEYCYLINDER INSTALLATION(1) If equipped with an automatic transmission,

place shifter in PARK position .(2) Position key cylinder into steering column as it

would normally be in the ON position .(3) Press key cylinder into column until it snaps

into position .(4) Check mechanical operation of switch . Auto-

matic Transmission : Be sure transmission lever islocked in PARK position after key removal. If key isdifficult to rotate or is difficult to remove, the shift

80 - 22

IGNITION SYSTEM


lever-to-steering column cable may be out of adjust-ment or defective . Refer to Group 21, Transmissionfor procedures . Manual Transmission: Be sure keycannot be removed until release lever is operated . Ifkey can be removed, release lever mechanism may bedefective . Release lever mechanism is not servicedseparately. If repair is necessary, the steering columnmust be replaced . Refer to Group 19, Steering forprocedures .

(5) Connect negative cable to battery.(6) Check electrical operation of switch .

SHIFTER/IGNITION INTERLOCKOn models equipped with an automatic transmis-

sion, a cable connects the ignition switch with thefloor shift lever. The shifter will be locked in thePARK position when the ignition key is in the LOCKor ACCESSORY positions . The cable can be adjustedor replaced . Refer to Group 21, Transmissions forprocedures . The ignition interlock device within thesteering column is not serviceable . If service is nec-essary, the steering column must be replaced. Referto Group 19, Steering for procedures .

SPECIFICATIONS

VECI LABEL SPECIFICATIONSIf anything differs between the specifications found

on the Vehicle Emission Control Information (VECI)label and the following specifications, use specifica-tions on VECI label . The VECI label is located in theengine compartment.

IGNITION TIMINGIgnition timing is not adjustable on any engine.

Refer to Ignition Timing in the Diagnostics/ServiceProcedures section of this group for more informa-tion .

ENGINE FIRING ORDER-2 .5L 4-CYLINDERENGINE

FIRING ORDER :1 3 4 2CLOCKWISEROTATION

FIRING ORDER :1 5 3 6 2 4CLOCKWISEROTATION

ENGINE FIRING ORDER-4 .OL 6-CYLINDERENGINE

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MD-6

J908D-7

ignition system - home page for l. w. (bill) hughes iii

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