GM Storm/Spectrum 1985-1993 Repair Guide

Timing

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ADJUSTMENT



Conventional Spark Control Ignition

See Figure 1

  1. Set the parking brake and block the wheels.
  2.  
  3. Place the manual transaxle in N or the automatic transaxle in the P detent.
  4.  
  5. Allow the engine to reach normal operating temperature. Make sure that the choke valve is open. Turn off all of the accessories.
  6.  
  7. If equipped with power steering, place the front wheels in a straight line.
  8.  
  9. Disconnect and plug the distributor vacuum line, the canister purge line, the EGR vacuum line and the ITC valve vacuum line at the intake manifold.
  10.  
  11. Connect a timing light to the No. 1 spark plug wire and a tachometer to the tachometer filter connector on the coil, tachometer filter is mounted near distributor hold down bolt.
  12.  

Check the idle speed and adjust as needed.

  1. Loosen the distributor flange bolt.
  2.  
  3. Using the timing light, align the notch on the crankshaft pulley with the mark on the timing cover by turning the distributor.
  4.  

Adjust the timing to 15 degrees BTDC at 750 rpm (MT) or 10 degrees BTDC at 1000 rpm (AT).

  1. When adjustment has been made, hold the distributor to keep it from turning and tighten the distributor hold-down bolt. Recheck the timing to make sure the distributor position was not changed. Reconnect all vacuum lines.
  2.  



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Fig. Fig. 1: Timing mark location - Spectrum

Electronic Spark Control System

See Figures 2 and 3

  1. Apply the parking brake, block the wheels and place the transaxle in N or P .
  2.  
  3. Connect a tachometer to the battery and the diagnostic connector. Do not ground the tachometer terminal.
  4.  
  5. Run the engine until normal operating temperatures are reached, then stop the engine.
  6.  
  7. Connect a fused jumper wire between terminals 1 and 3 on the ALDL connector (the white connector located under the right hand instrument panel).
  8.  
  9. Using a timing light, connect it to the No. 1 spark plug wire. Loosen the distributor hold-down bolt until it is only finger tight.
  10.  
  11. Depress the accelerator pedal and start the engine, and allow the engine to idle.
  12.  
  13. Aim the timing light at the timing cover plate near the crankshaft pulley; the white notch on the crankshaft pulley should align with the 10 degree mark on the timing cover scale.
  14.  
  15. To adjust the engine timing, turn the distributor slightly to align the marks as specified. When properly adjusted, hold the distributor to keep it from turning and tighten the distributor hold-down bolt to 14 ft. lbs. (20 Nm). Recheck the timing to make sure the distributor position was not changed while tightening the distributor flange bolt.
  16.  
  17. When the adjustment is correct, remove the jumper wire from the ALDL connector and turn the ignition OFF .
  18.  
  19. Disconnect the timing light and the tachometer.
  20.  



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Fig. Fig. 2: Terminals 1 and 3 of the ALDL connector must be jumpered in order to disable the ECM controlled spark advance system



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Fig. Fig. 3: Ignition spark control schematic - 1993 Storm

 
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