GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

    • Inspect the flywheel ring gear for damage or unusual wear.
    • Shim the starter as required.
    • In order to add pinion to ring gear clearance a full size shim must be used. Do not shim only one starter mounting bolt. There are 3 shims available in different shapes, for clearance, all are 1 mm (0.039 in.) thick.

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check for Engine Electrical?

Go to Step 2

Go to Diagnostic System Check - Engine Electrical

2

Start the engine.

Does the starter operate normally?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Start the engine while listening to the starter motor turn.

Is there a loud "whoop", it may sound like a siren if the engine is revved while the starter is engaged, after the engine starts, but while the starter is still held in the engaged position?

Go to Step 6

Go to Step 4

4

Do you hear a "rumble", a "growl", or, in some cases, a "knock" as the starter is coasting down to a stop after starting the engine?

Go to Step 7

Go to Step 5

5

Important: This is often diagnosed as a starter drive gear hang-in or a weak solenoid.

When the engine is cranked, do you hear a high-pitched whine after the engine cranks and starts normally?

Go to Step 8

Go to Step 7

6

Inspect the flywheel ring gear for the following:

    • Chipped gear teeth
    • Missing gear teeth
    • Milled teeth

Is the flywheel bent, or does it have damaged teeth?

Go to Step 9

Go to Step 10

7

  1. Remove the starter motor. Refer to Starter Motor Replacement .
  2. Inspect the starter motor bushings and clutch gear.

Does the clutch gear have chipped or milled teeth or worn bushings?

Go to Step 10

Go to Step 9

8

Shim the starter motor away from the flywheel by adding shims between the starter motor and the engine block one at a time.

Flywheel runout may make this noise appear to be intermittent.

Did you complete the repair?

Go to Step 11

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9

Replace the flywheel. Refer to Engine Flywheel Replacement in Engine Mechanical-3.1L or Engine Flywheel Replacement in Engine Mechanical-3.8L.

Did you complete the replacement?

Go to Step 11

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10

Replace the starter motor. Refer to Starter Motor Replacement .

Did you complete the replacement?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3