GM Full-Size Trucks 1980-1987 Repair Guide

Starter

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TESTING




CAUTION
Never operate the starter motor than 30 seconds at a time without pausing to allow it to cool for at least two minutes. Overheating, caused by excessive cranking, will seriously damage the starter motor.

Basic starter testing can be done without tools. The problem is a bad battery and a defective starter cause the same symptoms. First test and charge the battery to confirm it is in good condition.

  1. Place a voltmeter across the battery and try to start the car.
  2.  
  3. If the starter makes no sounds and the voltmeter didn't move in the last step, the wires from the ignition switch to the starter need to be checked. Check for 12 volts by connecting a voltmeter between the starter solenoid's small gauge (little) wire and ground while the ignition is turned to start.

    If 10 volts or more is measured, the problem is most likely the open starter solenoid.
     
    If no voltage is measured, the problem is not the starter but the ignition switch, neutral safety switch or wiring to the starter.
     
    If less than 10 volts is measured but some voltage is measured, check the battery and the battery cables.
     

  4.  
  5. If the starter clicks, and the voltmeter moves very little. Check the solenoid, battery cables and wire connections.
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  7. If the engine cranks very slow or seems to jam and the battery and battery cables are OK, the starter is the probable problem.
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  9. If the vehicle is hard to crank warm, but after given time to cool cranks easier. The starter is the probable problem.
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  11. Before condemning the starter always check the engine mechanical condition. A good starter can not crank over a damaged engine, or engine that has been extremely overheated, is low on oil, has extremely thick and dirty oil.
  12.  

REMOVAL & INSTALLATION



See Figures 1, 2, 3 and 4

The following is a general procedure for all trucks, and may vary slightly depending on model and series.

The starters on some engines require the addition of shims to provide proper clearance between the starter pinion gear and the flywheel. The shims are available in 0.015 inch sizes from General Motors dealers.

  1. Disconnect the battery ground cable.
  2.  
  3. Raise and support the vehicle with jackstands.
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  5. Disconnect and tag all wires at the solenoid terminals.
  6.  

Sometimes, the wire fasteners may be extremely difficult to reach with the starter installed. If the wires cannot be disconnected, wait until the starter bolts and removed and the starter can be lowered slightly for better access, but do not allow the starter to hang by the wires or they could be damaged.

  1. Reinstall all nuts as soon as they are removed, since the thread sizes are different.
  2.  



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Fig. Fig. 1 Loosen the nuts retaining the starter solenoid wires and disconnect the harness



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Fig. Fig. 2: Support the starter by hand and withdraw the mounting bolts

  1. If equipped, remove the mounting bracket nuts or bolts, as applicable.
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  3. On engines with a solenoid heat shield, remove the front bracket upper bolt and detach the bracket from the starter.
  4.  


WARNING
The starter assembly is very heavy. Be careful to fully support the assembly when removing the mounting bolts. The assembly is heavy enough to cause injury, especially if it should fall on your head when the last mounting bolt is loosened.



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Fig. Fig. 3: If necessary, the starter may be lowered slightly for access to disconnect the solenoid wires. If this is done, be careful not to stretch or damage the wiring

  1. Support the starter by hand, then loosen and remove the 2 mounting bolts. Lower the starter front end first, and then remove the unit from the truck. If any shims were installed between the starter and the engine block, note the size and location of the shims to assure proper installation.
  2.  
  3. Reverse the removal procedures to install the starter. If any shims were present, be sure to reposition them as noted during removal in order to assure proper starter operation. Torque the two mounting bolts to 25-35 ft. lbs.
  4.  



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Fig. Fig. 4: Starter mountings

Shimming the Starter

See Figures 5, 6 and 7

Starter noise during cranking and after the engine fires is often a result of too much or too little distance between the starter pinion gear and the flywheel. A high pitched whine during cranking (before the engine fires) can be caused by the pinion and flywheel being too far apart. Likewise, a whine after the engine starts (as the key is released) is often a result of the pinion-flywheel relationship being too close. In both cases flywheel damage can occur. Shims are available in 0.015 inch sizes to properly adjust the starter on its mount. You will also need a flywheel turning tool, available at most auto parts stores or from any auto tool store.



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Fig. Fig. 5: Shimming the starter motor; diesel 350 shown at right



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Fig. Fig. 6: Flywheel to pinion clearance check



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Fig. Fig. 7: Meshing starter teeth

If your car's starter emits the above noises, follow the shimming procedure below:

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the flywheel inspection cover on the bottom of the bellhousing.
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  5. Using the flywheel turning tool, turn the flywheel and examine the flywheel teeth. If damage is evident, the flywheel should be replaced.
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  7. Insert a screwdriver into the small hole in the bottom of the starter and move the starter pinion and clutch assembly so the pinion and flywheel teeth mesh. If necessary, rotate the flywheel so that a pinion tooth is directly in the center of the two flywheel teeth and on the centerline of the two gears, as shown in the accompanying illustration.
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  9. Check the pinion-to-flywheel clearance by using a 0.020 inch wire gauge (a spark plug wire gauge may work here, or you can make your own). Make sure you center the pinion tooth between the flywheel teeth and the gauge, NOT in the corners, as you may get a false reading. If the clearance is under this minimum, shim the starter away from the flywheel by adding shim(s) one at a time to the starter mount. Check clearance after adding each shim.
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  11. If the clearance is a more than 0.050 inch, shim the starter towards the flywheel. Broken or severely mangled flywheel teeth are also a good indicator that the clearance here is too great. Shimming the starter towards the flywheel is done by adding shims to the outboard starter mounting pad only. Check the clearance after each shim is added. A shim of 0.015 inch at this location will decrease the clearance about 0.010 inch.
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STARTER SOLENOID REPLACEMENT



  1. Disconnect the negative battery cable.
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  3. Remove the starter from the vehicle.
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  5. Remove the screw and washer from the field strap terminal.
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  7. Remove the two solenoid-to-housing retaining screws and the motor terminal bolt.
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  9. Remove the solenoid by twisting the unit 90 degrees.
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  11. To replace the solenoid, reverse the above procedure. Make sure the return spring is on the plunger, and rotate the solenoid unit into place on the starter.
  12.  

See Figures 8 and 9



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Fig. Fig. 8: Troubleshooting Basic Starting System Problems



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Fig. Fig. 9: Starter Specifications

 
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