Engine won't start
1. If the starter fails to crank the engine, check the battery and starter referring to Section 12.
2. Disconnect the high voltage wire from either spark plug and bring its end about 5mm from the cylinder head using well insulated pliers. Crank the engine quickly with the starter, there should be an even blue spark. If so, remove the spark plug and adjust the gap as described in Chapter 9.
3. If there is no spark, disconnect the high voltage center wire from the distributor breaker cover and check if there is an ignition spark, as described in point 2. If a spark now appears, check the distributor breaker cover, distributor slider, and high voltage wires as described in Chapters 3 and 10.
4. If there is no spark, check the resistance of the main high voltage wire as described in Chapter 10, replace as needed. If wiring is OK, check that all wiring and multi-pin plugs are secure.
5. Check the ignition coil as described in Chapter 6.
6. If the above check showed no damage and there is still no ignition spark, the control unit may be faulty. Consult your GM dealer for further testing, or replace with a new one.
Misfire
7. If there are regular misfires, start the engine and set the idle speed to fast. Remove the high voltage wire from each spark plug and listen for a change in engine performance.
8. If, when disconnecting the high-voltage wire from any spark plug, no change in engine operation is noted, then this circuit is defective. Removing the wiring from one of the good cylinders will highlight the misfire.
9. Remove the high voltage wire from the end of the defective spark plug and bring it about 5 mm from the cylinder head. Restart the engine. If the spark is fairly strong and regular, the spark plug is damaged.
10. Spark plug may be loose, cracked insulation, or possibly incorrect gap. Replace the plug or set the required gap, then check again.
11. If there is no ignition spark at the end of the wire, or it is weak and intermittent, check the high voltage wire from the distributor to the spark plug. If the insulation is split, or the resistance is incorrect, replace the wiring. Check the connection on the cover of the breaker-distributor.
12. If there is still no ignition spark, check the condition of the distributor cap. Replace if necessary.
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