Idle Stabilizer Check

If engine will not start, check idle stabilizer first. See Fig 1. Remove both connectors from idle stabilizer and connect them together. This by-passes the idle stabilizer connecting the ignition control unit directly to the distributor. If engine now starts, idle stabilizer is defective.

Fig 1: Idle Stabilizer and Ignition Control Unit
Courtesy of NOT AVAILABLE
In other cases where engine starts but idle stabilizer is suspected, by-pass the stabilizer by removing the 2 connectors and connecting them together. Turn off all electrical accessories and set idle speed and timing.
Then, reconnect the idle stabilizer. Ignition timing at idle may fluctuate, but should be between 3° ATDC (±3°). Turn all power accessories in step 2) back on. Ignition timing should be advanced to keep engine speed to specifications. If not, replace idle stabilizer.
NOTE: An alternative manner of checking idle stabilizer can be used. With engine oil temperature above 140° F (60° C), connect test equipment according to manufacturer's instructions. Start engine and slowly increase engine speed while applying foot brake. Let engine idle. On vehicles with manual transmission, engage 4th gear and release clutch slowly. On vehicles with automatic transmission, move selector into "DRIVE" position. As engine load increases, ignition timing must advance. If not, idle stabilizer control unit is defective and must be replaced.