GM 10455070 Motor Assembly, Start Sd260

To diagnose slow cranking, run the engine until it reaches normal operating temperature, then stop the engine, disconnect the coil wire from the distributor cap, and ground it on the engine.

Remove and bench-test the starter motor assembly. Check the solenoid plunger, shift lever, and overrunning clutch for proper operation to identify any defects in the starter motor or solenoid. If the pinion drive extends but doesn't rotate, the solenoid is operational but the starter motor is defective. If there's no movement and the solenoid clicks, either the solenoid or starter motor is defective. If the solenoid plunger extends and rotates the pinion drive, the starter assembly is operating correctly.

Remove the starter motor shield.

To adjust the shim for the starter, follow these steps:Remove the flywheel housing cover and inspect the flywheel or drive plate for signs of unusual wear.

Label and disconnect the wires from the terminals on the starter motor and solenoid.

The battery cable clamps for cleanliness and tightness, the battery cables, the battery's condition, the starter motor wiring and connections, the starter motor mounting bolts, the fuses in the engine compartment fuse box, the ignition switch circuit, the starter relay, and the clutch start switch (manual transmission) or the Park/Neutral position switch (automatic transmission).

To adjust the shim for the starter, follow these steps: Remove the flywheel housing cover and inspect the flywheel or drive plate for signs of unusual wear. Measure the clearance between the top of the flywheel ring gear tooth and the bottom of the pinion tooth on the starter using a wire-type feeler gauge (round diameter). Normal clearance should be 0.01 to 0.06 inches. If the starter clearance is less than 0.02 inches and the starter whines after engagement, add a 0.04 shim to gain clearance (avoid using more than two shims). If the starter clearance is more than 0.06 inches and the starter whines during engagement, remove a 0.04 shim to gain clearance (avoid removing more than two shims). To install a shim, loosen the inside bolt, remove the outer bolt, and slide the shim between the engine and the starter without removing the starter from the engine block.

To adjust the shim for the starter, follow these steps: Remove the flywheel housing cover and inspect the flywheel or drive plate for signs of unusual wear. Measure the clearance between the top of the flywheel ring gear tooth and the bottom of the pinion tooth on the starter using a wire-type feeler gauge (round diameter). Normal clearance should be 0.01 to 0.06 inches. If the starter clearance is less than 0.02 inches and the starter whines after engagement, add a 0.04 shim to gain clearance (avoid using more than two shims). If the starter clearance is more than 0.06 inches and the starter whines during engagement, remove a 0.04 shim to gain clearance (avoid removing more than two shims). To install a shim, loosen the inside bolt, remove the outer bolt, and slide the shim between the engine and the starter without removing the starter from the engine block.

First, check that the shift lever is in Neutral or Park (for automatic transmission) or that the clutch pedal is depressed (for manual transmission). Then, ensure that the battery is charged and that all cables are securely connected at the battery and starter solenoid terminals.

If the solenoid clicks but the starter motor does not operate, the issue may lie with the battery, main solenoid contacts, or the starter motor itself.

To adjust the shim for the starter, follow these steps: Remove the flywheel housing cover and inspect the flywheel or drive plate for signs of unusual wear. Measure the clearance between the top of the flywheel ring gear tooth and the bottom of the pinion tooth on the starter using a wire-type feeler gauge (round diameter). Normal clearance should be 0.01 to 0.06 inches. If the starter clearance is less than 0.02 inches and the starter whines after engagement, add a 0.04 shim to gain clearance (avoid using more than two shims). If the starter clearance is more than 0.06 inches and the starter whines during engagement, remove a 0.04 shim to gain clearance (avoid removing more than two shims). To install a shim, loosen the inside bolt, remove the outer bolt, and slide the shim between the engine and the starter without removing the starter from the engine block.

If the starter motor spins but the engine does not crank, the overrunning clutch in the starter motor may be slipping, and you'll need to replace the motor.