Файл: 92FWD_8D.pdf

Inspect the coil for arcing. Test the coil according to coil tester manufacturer's instructions. Test coil primary and secondary resistance. Replace any coil that does not meet specifications. Refer to the Coil Resistance chart.

If the ignition coil is replaced due to a burned tower, carbon tracking, arcing at the tower, or damage to the terminal or boot on the coil end of the secondary cable, the cable must be replaced. Arcing at the tower will carbonize the nipple which, if it is connected to a new coil, will cause the coil to fail.

If a secondary cable shows any signs of damage, the cable should be replaced with a new cable and new terminal. Carbon tracking on the old cable can cause arcing and the failure of a new coil.

TESTING FOR SPARK AT COIL

WARNING: APPLY PARKING BRAKE AND/OR BLOCK THE WHEELS BEFORE PERFORMING ANY TEST WITH THE ENGINE RUNNING.

CAUTION: Spark plug cables may be damaged if this test is performed with more than 1/4 inch clearance between the cable and engine ground.

Remove the coil secondary cable from the distributor cap. Hold the end of cable about 6 mm (1/4-inch) away from a good engine ground (Fig. 1). Crank the engine and inspect for spark at the coil secondary cable.

Fig. 1 Checking for Spark

There must be a constant spark at the coil secondary cable. If the spark is constant, have a helper continue to crank engine and, while slowly moving coil secondary cable away from ground, look for arcing at the coil tower. If arcing occurs at the tower, replace the coil. If spark is not constant or there is no spark, proceed to the failure to start test.

If a constant spark is present and no arcing occurs at the coil tower, the ignition system is producing the

necessary high secondary voltage. However, make sure that the spark plugs are firing. Inspect the distributor rotor, cap, spark plug cables, and spark plugs. If they are in proper working order, the ignition system is not the reason why the engine will not start. Inspect the fuel system and engine for proper operation.

FAILURE TO START TESTÐ2.5L TBI AND 3.0L ENGINES

Before proceeding with this test make sure Testing For Spark At Coil has been performed. Failure to do this may lead to unnecessary diagnostic time and wrong test results.

WARNING: BE SURE TO APPLY PARKING BRAKE AND/OR BLOCK WHEELS BEFORE PERFORMING ANY TEST WITH THE ENGINE RUNNING.

(1)Battery voltage must be at least 12.4 volts to perform test.

(2)Crank the engine for 5 seconds while monitoring the voltage at the coil positive (+) terminal (Fig. 2 or Fig. 3). If the voltage remains near zero during the entire period of cranking, refer to Group 14 for OnBoard Diagnostic checks. Also, refer to the DRB II tester and the appropriate Powertrain Diagnostic Procedures manual. These checks will help diagnose problems with the engine controller and auto shutdown relay.

Fig. 2 Coil TerminalsÐ2.2L TBI, 2.5L TBI and

Turbo I Engines

(3)If voltage is at near-battery voltage and drops to zero after 1-2 seconds of cranking, refer to On-Board Diagnostic in Group 14. Also, refer to the DRB II tester and the appropriate Powertrain Diagnostic Procedures manual. These tests will help check the distributor reference pickup circuit to the engine controller.

(4)If voltage remains at near battery voltage during the entire 5 seconds, with the key off, remove

Fig. 3 Coil TerminalsÐ3.0L Engine

the engine controller 60-way connector. Check the 60-way connector for any terminals that are pushed out or loose.

(5)Remove the connector to coil (+) and connect a jumper wire between battery (+) and coil (+).

(6)Using the special jumper (Fig. 4), momentarily ground terminal #19 of the 60-way connector (Fig. 5). A spark should be generated when the ground is removed.

Fig. 4 Special Jumper to Ground Coil Negative

Fig. 5 60-Way Electrical Connector, Engine

Controller

(7)If spark is generated, replace the engine controller.

(8)If no spark is seen, use the special jumper to ground the coil (-) terminal directly.

(9)If spark is produced, inspect wiring harness for an open condition.

(10) If no spark is produced, replace the ignition coil.

POOR PERFORMANCE TEST

To prevent unnecessary diagnostic time and possible incorrect results, the Testing For Spark At Coil procedure should be performed before this test.

WARNING: APPLY PARKING BRAKE AND/OR BLOCK THE WHEELS BEFORE PERFORMING ANY ENGINE RUNNING TESTS.

Check and adjust basic timing (refer to the specification section of this group and see service procedures).

COOLANT TEMPERATURE SENSOR TEST

(1)With key off, disconnect wire connector from coolant temperature sensor (Fig. 6).

(2)Connect one lead of ohmmeter to one terminal of coolant temperature sensor.

(3)Connect the other lead of ohmmeter to remaining terminal of coolant temperature sensor. The ohmmeter should read as follows;

²Engine/Sensor at normal operating temperature around 200°F should read approximately 700 to 1,000 ohms.

²Engine/Sensor at room temperature around 70°F, ohmmeter should read approximately 7,000 to 13,000 ohms.

Refer to On Board Diagnostics in the General Diagnosis section of Group 14. Also, refer to the DRB II tester and the appropriate Powertrain Diagnostic Procedures manual for additional test procedures.

Fig. 6 Coolant Temperature Sensor Test

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR TEST

Refer to the DRB II tester and appropriate Powertrain Diagnostic Procedures manual for further test procedures.

DETONATION (KNOCK) SENSOR

Refer to the DRB II tester and appropriate Powertrain Diagnostic Procedures manual for test procedures.

ENGINE CONTROLLER

The engine controller is located next to the battery (Fig. 1).

next to the thermostat housing (Fig. 3).

REMOVAL

(1)Drain cooling system until coolant level is below coolant sensor. Refer to Group 7, Cooling System.

(2)Disconnect electrical connector from sensor.

(3)Remove sensor from engine.

INSTALLATION

(1)Install coolant sensor. Tighten 2.2L TBI, 2.5L TBI or Turbo I engine coolant sensor to 28 NIm (20

ft. lbs.) torque. Tighten the 3.0L engine coolant sensor to 7 NIm (60 in. lbs.) torque.

(2)Connect electrical connector to sensor.

(3)Fill cooling system. Refer to Group 7, Cooling System.

Fig. 3 Coolant Temperature SensorÐ3.0L Engine

IGNITION COILÐ2.2L TBI, 2.5L TBI AND TURBO I ENGINES

The ignition coil mounts to the thermostat housing (Fig. 4).

Fig. 4 Ignition CoilÐ2.2L TBI, 2.5L TBI and Turbo I

Engines

REMOVAL

(1)Disconnect the coil to distributor ignition cable (Fig. 4).

(2)Disconnect the wiring harness connector from the coil.

(3) Remove ignition coil mounting screws.

INSTALLATION

(1)Install ignition coil onto the bracket. Tighten the screws to 9.5 NIm (85 in. lbs.) torque.

(2)Connect the wiring harness connector.

(3)Connect the coil to distributor ignition cable.

IGNITION COILÐ3.0L ENGINES

The ignition coil is located at the back of the intake manifold (Fig. 5).

Fig. 5 Ignition CoilÐ3.0L Engine

REMOVAL

(1)Remove air cleaner assembly.

(2)Disconnect ignition cable from coil.

(3)Disconnect wiring harness connector from coil.

(4)Remove coil mounting screws.

INSTALLATION

(1)Loosely install ignition coil on intake manifold. Tighten the intake manifold fastener to 13 NIm (115

in. lbs.) torque. Tighten ignition coil bracket fasteners to 10 NIm (96 in. lbs.) torque.

(2)Connect the wiring harness connector.

(3)Connect the coil to distributor ignition cable.

(4)Install the air cleaner assembly. Tighten the air cleaner fasteners to 25 NIm (225 in. lbs.) torque.

SPARK PLUG SERVICE

When replacing the spark plug and coil cables, route the cables correctly and secure them in the appropriate retainers. Incorrectly routed cables can cause the radio to reproduce ignition noise. It can also cause cross ignition of the spark plugs or short circuit the cables to ground.

SPARK PLUG REMOVAL

Always remove cables by grasping at boot, rotating the boot 1/2 turn, and pulling straight back in a steady motion.

8D - 16 IGNITION SYSTEMS

(1)Prior to removing the spark plug spray compressed air around the spark plug hole and the area around the spark plug.

(2)Remove the spark plug using a quality socket with a rubber or foam insert.

(3)Inspect the spark plug condition. Refer to Spark Plug Condition in this section.

SPARK PLUG GAP ADJUSTMENT

Check the spark plug gap with a gap gauge. If the gap is not correct, adjust it by bending the ground electrode (Fig. 6).

Fig. 6 Setting Spark Plug GapÐTypical

SPARK PLUG INSTALLATION

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

(2)Tighten spark plugs to 28 NIm (20 ft. lbs.) torque.

(3)Install spark plug cables over spark plugs.

IDLE RPM TESTÐ2.5L AND 3.0L ENGINES

WARNING: APPLY PARKING BRAKE AND/OR BLOCK WHEELS BEFORE PERFORMING IDLE CHECK OR ADJUSTMENT, OR ANY TESTS WITH A RUNNING ENGINE.

Engine idle set rpm should be tested and recorded when the vehicle is first brought into shop for testing. This will assist in diagnosing complaints of engine stalling, creeping and hard shifting on vehicles equipped with automatic transmissions.

Proceed to the Throttle Body Minimum Airflow procedures.

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THROTTLE BODY MINIMUM AIR FLOW CHECK PROCEDUREÐ2.2L TBI AND 2.5L TBI ENGINES

(1)Connect Diagnostic Readout Box II (DRBII).

(2)Remove air cleaner assembly. Plug the heated air door vacuum hose.

(3)Warm engine in Park or Neutral until the cooling fan has cycled on and off at least once.

(4)Hook-up timing check device and tachometer.

(5)Disconnect the coolant temperature sensor and set basic timing to 12°BTDC 6 2°BTDC.

(6)Shut off engine. Reconnect coolant temperature sensor.

(7)Disconnect the PCV valve hose from the intake manifold nipple.

(8)Attach Air Metering Fitting #6457 (Fig. 7) to the intake manifold PCV nipple.

Fig. 7 Air Metering Fitting

(9)Restart the engine, allow engine to idle for at least one minute.

(10)Using the DRBII, Access Min Airflow Idle Spd in the sensor read test mode.

(11)The following will then occur:

²AIS motor will fully close.

²Idle spark advance will become fixed.

²Idle fuel will be provided at a set value.

²Engine RPM will be displayed on Diagnostic Readout Box II (DRBII).

(12)Check idle RPM with tachometer. If idle RPM is within the specifications listed below, then the throttle body min. air flow is set correctly.

IDLE SPECIFICATIONS