Starter Motor Noise
To correct starter motor noise during starting, use the following procedure
| Checks | Action |
|---|---|
| Check for a high-pitched whine during cranking, before the engine fires. The engine cranks and fires properly. | The distance is too great between the starter pinion and the flywheel. Shimming the starter toward the flywheel is required. |
| Check for a high-pitched whine after the engine fires, as the key is being released. The engine cranks and fires properly. This intermittent complaint is often diagnosed as "starter hang-in" or "solenoid weak." | The distance is too small between the starter pinion and the flywheel. Shimming the starter away from the flywheel is required. |
| Check for a loud "whoop" after the engine fires but while the starter is still held engaged. The sound is like a siren if the engine is revved while the starter is engaged. | The most probable cause is a defective clutch. A new clutch will often correct this problem. |
| Check for a "rumble," a "growl," or, in severe cases, a "knock" as the starter is coasting down to a stop after starting the engine. | The most probable cause is a bent or unbalanced starter armature. A new armature will often correct this problem. |
STARTER MOTOR NOISE - DIAGNOSTIC PROCEDURES
If the complaint is noise, correction can be achieved by proper shimming as follows
- Check for a bent or a worn flywheel.
- Start the engine and carefully touch the outside diameter of the rotating flywheel ring gear with chalk or a crayon to show the high point of the tooth runout. Turn the engine OFF and rotate the flywheel so that the marked teeth are in the area of the starter pinion gear.
- Disconnect the negative battery cable to prevent cranking the engine.
- Check the pinion-to-flywheel clearance by using a wire gauge of 0.5 mm (0.02 in.) minimum thickness (or diameter). Center a pinion tooth between 2 flywheel teeth and the gauge. Do not gauge in the corners, where a misleading larger dimension may be observed. If the clearance is under this minimum, shimming the starter away from the flywheel is required.
- If the clearance approaches 1.5 mm (0.06 in.) or more, shimming the starter toward the flywheel is required. This condition is generally the cause of broken flywheel teeth or the starter housing. Shim the starter toward the flywheel by shimming only the outboard starter mounting pad. A shim of 0.40 mm (0.016 in.) thickness at this location will decrease the clearance by approximately 0.30 mm (0.012 in.). If normal starter shims are not available, plain washers or other suitable material may be used as shims.
Scheme 2
Scheme 3
Scheme 4
- Disconnect the negative battery cable.
- Remove the air hose inlet hose bolts.
- Remove the starter solenoid nut to disconnect the electrical cable.
- Disconnect the starter electrical connector.
- Remove the starter-to-engine block mounting bolt and the starter-to-transaxle mounting bolt.
- Remove the starter assembly.
Scheme 5
Scheme 6
Scheme 7
Scheme 8
Scheme 9
Scheme 10
Scheme 11
Scheme 12
Scheme 13
Scheme 14
Scheme 15
Scheme 16
Scheme 17
Scheme 18
Scheme 19
- Remove the starter. Refer to «Starter Removal»(ref-257293-S24857688332007070900000) .
- Remove the starter through-bolts.
- Remove the commutator end frame and brush holder assembly.
- Inspect the brushes, the pop-out springs, and the brush holders for wear and damage. Replace the assembly, if needed.
- Check the armature to see if it turns freely. If the armature does not turn freely, break down the assembly immediately, starting with Step 14 . Otherwise, give the armature a no-load test.
- To begin the no-load test, close the switch and compare the RPM, the current, and the voltage readings with the specifications. Refer to «Starter Specifications»(ref-257293-S03511214942007070900000) . Make disconnections only with the switch open. Use the test results as follows: CAUTION: Complete the testing in a minimum amount of time to prevent overheating and damaging the solenoid. NOTE: If the specified current draw does not include the solenoid, deduct from the armature reading the specified current draw of the solenoid hold-in winding. Rated current draw and no-load speed indicate a normal condition for the starter motor. Low RPM combined with high current draw is an indication of excessive friction caused by tight, dirty, or worn bearings; a bent armature shaft; a shorted armature; or a shorted field coils. Failure to operate with high current draw indicates a direct ground in the terminal or fields, or "frozen" bearings. Failure to operate with no current draw indicates an open field circuit, open armature coils, broken brush springs, worn brushes, high insulation between the commutator bars, or other causes which would prevent good contact between the brushes and the commutator. Low, no-load speed and low current indicate high internal resistance and high current draw, which usually mean shorted fields.
- Remove the solenoid assembly screws.
- Remove the field connector nut. Disconnect the field connector.
- Remove the plunger return spring.
- Test the solenoid windings by checking the current draw. NOTE: If the solenoid is not removed from the starting motor, the connector strap terminals must be removed from the terminal on the solenoid before making these tests. Check the hold-in windings by connecting an ammeter in series with a 12 V battery, the switch terminal, and to ground. Connect the carbon pile across the battery. Adjust the voltage to 10 V. The ammeter reading should be 13 - 19 A. Current will decrease as the windings heat up. Current draw readings that are over specifications indicate shorted turns or a ground in the windings of the solenoid. Both conditions require replacement of the solenoid. Current draw readings that are under specifications indicate excessive resistance. No reading indicates an open circuit.
- Check both windings, connecting them according to the preceding test. NOTE: Current will decrease as the windings heat up. Current draw readings that are over specifications indicate shorted turns or a ground in the windings of the solenoid. Both conditions require replacement of the solenoid. Current draw readings that are under specifications indicate excessive resistance. No reading indicates an open circuit. Ground the solenoid motor terminal. Adjust the voltage to 10 V. The ammeter reading should be 59 - 79 A. Check the connections and replace the solenoid, if necessary.
- Slide the field frame with enclosed armature assembly away from the starter assembly.
- Remove the shield.
- Separate the field frame from the armature.
- Inspect the shaft and the pinion for discoloration, damage, or wear. Replace, if necessary.
- Inspect the armature commutator. If the commutator is rough, it should be turned down. The outside diameter of the commutator must measure at least 26.9 - 27.1 mm (1.059 - 1.067 in.) after it is undercut or turned. Do not turn out-of-round commutators.
- Inspect the points where the armature conductors join the commutator bars. Make sure they have a good connection. A burned commutator bar is usually evidence of a poor connection.
- If test equipment is available, check the armature for short circuits by placing it on a growler, and holding back a saw blade over the armature core while the armature is rotated. If the saw blade vibrates, replace the armature.
- Recheck the armature after cleaning between the commutator bars. If the saw blade vibrates, replace the armature.
- Remove the locking ring from the groove in the driveshaft.
- Remove the pinion stop and the drive from the driveshaft.
- If not done in the previous steps, remove the screws that hold the solenoid assembly into the housing, and remove the nut from the field coil connector.
- Rotate the solenoid 90° and remove it along with the return spring.
- Remove the plunger with the boot and the shift lever assembly. Test the solenoid windings, if not done in Step 11 .
- When the starter motor is disassembled and the solenoid is replaced, it is necessary to check the pinion clearance. NOTE: The pinion clearance must be correct to prevent the buttons on the shift lever yoke from rubbing on the clutch collar during the cranking.
- Disconnect the motor field coil connector from the solenoid motor terminal and carefully insulate the connector.
- Connect one 12 V battery lead to the solenoid switch terminal and the other to the starter frame.
- Flash a jumper lead momentarily from the solenoid motor terminal to the starter frame, allowing shifting of the pinion in the cranking position, where it will remain until the battery is disconnected.
- Push the pinion back as far as possible to take up any movement, and check the clearance with a feeler gauge. The clearance should be 0.25 - 3.56 mm (0.01 - 0.14 in.). NOTE: A means for adjusting the pinion clearance is not provided on the starter motor. If the clearance does not fall within the limits, check for improper installation and replace all worn parts.