Jeep Cherokee (XJ): Starter motor noise - 2.5L engine. Starter motor. Starter relay

Jeep Cherokee (XJ) 1984 - 2001 Service Manual > Starting systems > Diagnosis and testing > Starter motor noise - 2.5L engine. Starter motor. Starter relay

Starter motor noise - 2.5L engine

See the Starter Motor Noise Diagnosis chart (Fig.

9). If the complaint is similar to Conditions 1 and 2 in the chart, correction can be made by placing shims between the starter motor and the engine block using the following procedures:

CONDITION

POSSIBLE CAUS

CORRECTION

1. VERY HIGH FREQUENCY WHINE BEFORE ENGINE STARTS; ENGINE STARTS OK. 1. Excessive distance between pinion gear and flywheel/drive plate gear. 1. Move starter motor toward flywheel/drive plate by removing shim(s), if possible.
2. VERY HIGH FREQUENCY WHINE AFTER ENGINE STARTS WITH IGNITION KEY RELEASED. ENGINE STARTS OK. 2. Insufficient distance between starter motor pinion gear and flywheel/drive plate runout can cause noise to be intermittent. 2. Shim starter motor away from flywheel/drive plate. Inspect flywheel/drive plate for damage; bent, unusual wear, and excessive runout. Replace flywheel/drive plate as necessary.
3. A LOUD "WHOOP" AFTER ENGINE STARTS WHILE STARTER MOTOR IS ENGAGED. 3. Most probably cause is defective overrunning clutch. 3. Replace starter motor.
4. A "RUMBLE," "GROWL," OR "KNOCK" AS STARTER MOTOR COASTS TO STOP AFTER ENGINE STARTS. 4. Most probable cause is bent or unbalanced starter motor armature. 4. Replace starter motor.

NOTE: A high frequency whine during cranking is normal for this starter motor.

FIG. 9 STARTER MOTOR NOISE DIAGNOSIS

(1) If the complaint is similar to Condition 1, the starter motor must be moved toward the starter ring gear by removing shims from both starter mounting pads on the engine block (Fig. 10). Refer to Starter Motor in the index of this service manual for the location of the proper starter motor removal and installation procedures.

NOTE: The shim thickness is 0.381 mm (0.015 in.).

These shims may be stacked if additional thickness is required.

Fig. 10 Starter Motor Shim
Fig. 10 Starter Motor Shim

1 - STARTER MOTOR SHIM

(2) If the complaint is similar to Condition 2, the starter motor must be moved away from the starter ring gear. This is done by installing shim(s) across both starter mounting pads on the engine block.

More than one shim may be required. Refer to Starter Motor in the index of this service manual for the location of the proper removal and installation procedures.

NOTE: This is a condition that will generally cause broken starter (flywheel/torque converter drive plate) ring gear teeth or broken starter motor housings.

Starter motor

Correct starter motor operation can be confirmed by performing the following free running bench test.

This test can only be performed with the starter motor removed from the vehicle. Refer to Starting System in the index of this service manual for the location of the proper starter motor specifications.

CAUTION: The 2.5L engine uses a permanent magnet starter. Permanent magnet starters are highly sensitive to hammering, shocks, external pressure and reverse polarity. This starter motor must never be clamped in a vise by the starter field frame. The starter should only be clamped by the mounting flange. Do not reverse the battery cable connections to this starter motor when testing. The permanent magnets may be damaged and the starter rendered unserviceable if it is subjected to any of these conditions.

STARTER MOTOR

(1) Remove the starter motor from the vehicle.

Refer to Starter Motor in the index of this service manual for the location of the proper starter motor removal and installation procedures.

(2) Mount the starter motor securely in a softjawed bench vise. The vise jaws should be clamped on the mounting flange of the starter motor. Never clamp on the starter motor by the field frame.

(3) Connect a suitable volt-ampere tester and a 12-volt battery to the starter motor in series, and set the ammeter to the 100 ampere scale. See the instructions provided by the manufacturer of the volt-ampere tester being used.

(4) Install a jumper wire from the solenoid terminal to the solenoid B(+) terminal stud. The starter motor should operate. If the starter motor fails to operate, replace the faulty starter motor.

(5) Adjust the carbon pile load of the tester to obtain the free running test voltage. Refer to Starting System in the index of this service manual for the location of the proper starter motor free running test voltage specifications.

(6) Note the reading on the ammeter and compare this reading to the free running test maximum amperage draw. Refer to Starting System in the index of this service manual for the location of the proper starter motor free running test maximum amperage draw specifications.

(7) If the ammeter reading exceeds the maximum amperage draw specification, replace the faulty starter motor.

STARTER SOLENOID

This test can only be performed with the starter motor removed from the vehicle.

(1) Remove the starter motor from the vehicle.

Refer to Starter Motor in the index of this service manual for the location of the proper starter motor removal and installation procedures.

(2) Disconnect the wire from the solenoid field coil terminal.

(3) Check for continuity between the solenoid terminal and the solenoid field coil terminal with a continuity tester (Fig. 11). There should be continuity. If OK, go to Step 4. If not OK, replace the faulty starter motor.

(4) Check for continuity between the solenoid terminal and the solenoid case (Fig. 12). There should be continuity. If not OK, replace the faulty starter motor.

Starter relay

The starter relay (Fig. 13) is located in the Power Distribution Center (PDC), in the engine compartment.

Refer to the fuse and relay layout label affixed to the underside of the PDC cover for starter relay identification and location. Refer to Starting System in the index of this service manual for the location of complete starting system wiring diagrams.

Fig. 11 Continuity Test Between Solenoid Terminal and Field Coil Terminal - Typical
Fig. 11 Continuity Test Between Solenoid Terminal and Field Coil Terminal - Typical

1 - SOLENOID 2 - SOLENOID TERMINAL 3 - OHMMETER 4 - FIELD COIL TERMINAL

Fig. 12 Continuity Test Between Solenoid Terminal and Solenoid Case - Typical
Fig. 12 Continuity Test Between Solenoid Terminal and Solenoid Case - Typical

1 - SOLENOID 2 - SOLENOID TERMINAL 3 - OHMMETER

RELAY TEST

(1) Remove the starter relay from the PDC. Refer to Starter Relay in the index of this service manual for the location of the proper starter relay removal and installation procedures.

(2) A relay in the de-energized position should have continuity between terminals 87A and 30, and no continuity between terminals 87 and 30. If OK, go to Step 3. If not OK, replace the faulty relay.

(3) Resistance between terminals 85 and 86 (electromagnet) should be 75 6 5 ohms. If OK, go to Step 4. If not OK, replace the faulty relay.

(4) Connect a battery to terminals 85 and 86.

There should now be continuity between terminals 30 and 87, and no continuity between terminals 87A and 30. If OK, perform the Relay Circuit Test that follows. If not OK, replace the faulty relay

Fig. 13 Starter Relay
Fig. 13 Starter Relay

RELAY CIRCUIT TEST

(1) The relay common feed terminal cavity (30) is connected to battery voltage and should be hot at all times. If OK, go to Step 2. If not OK, repair the open circuit to the fused B(+) fuse in the PDC as required.

(2) The relay normally closed terminal (87A) is connected to terminal 30 in the de-energized position, but is not used for this application. Go to Step 3.

(3) The relay normally open terminal (87) is connected to the common feed terminal (30) in the energized position. This terminal supplies battery voltage to the starter solenoid field coil. There should be continuity between the cavity for relay terminal 87 and the starter solenoid terminal at all times. If OK, go to Step 4. If not OK, repair the open engine starter motor relay output circuit to the starter solenoid as required.

(4) The coil battery terminal (86) is connected to the electromagnet in the relay. It is energized when the ignition switch is held in the Start position. On vehicles with a manual transmission, the clutch pedal must be blocked in the fully depressed position for this test. Check for battery voltage at the cavity for relay terminal 86 with the ignition switch in the Start position, and no voltage when the ignition switch is released to the On position. If OK, go to Step 5. If not OK with a manual transmission, disconnect the clutch pedal position switch wire harness connector and install a jumper wire between the two cavities in the body half of the connector and check for battery voltage again at the cavity for relay terminal 86. If now OK, replace the faulty clutch pedal position switch. If still not OK with a manual transmission or if not OK with an automatic transmission, check for an open or shorted fused ignition switch output (start) circuit to the ignition switch and repair, as required. If the fused ignition switch output (start) circuit is OK, refer to Ignition Switch and Key Lock Cylinder in the index of this service manual for the location of the proper ignition switch diagnosis and testing procedures.

(5) The coil ground terminal (85) is connected to the electromagnet in the relay. On vehicles with a manual transmission, it is grounded at all times. On vehicles with an automatic transmission, it is grounded through the park/neutral position switch only when the gearshift selector lever is in the Park or Neutral positions. Check for continuity to ground at the cavity for relay terminal 85. If not OK with a manual transmission, repair the open park/neutral position switch sense circuit to ground as required. If not OK with an automatic transmission, check for an open or shorted park/neutral position switch sense circuit to the park/neutral position switch and repair, as required. If the park/neutral position switch sense circuit checks OK, refer to Park/Neutral Position Switch in the index of this service manual for the location of the proper park/neutr

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