Direct Ignition troubleshooting summary (for no start)           

For problems with miss under load, first replace the plugs with properly gapped stock plugs.  If no fix, the problem may well be the D.I. unit.

For no start problems: Be advised that D.I. units can fail totally and without notice.  My car was running fine when I went to the grocery store, but when I came out, it wouldn't start.  The D.I. cassette had shorted internally.  Having done that, it also aggravated a corroded connector, which stopped conducting sufficient current.  The D.I. had to be replaced and the connector cleaned to get the car running again.

Do you hear the plug cleaning buzz after cranking, when the ignition is switched to OFF?  (You'll need to have someone else crank the engine and then switch it off, while you're listening at the DI unit ... some can be heard from inside the car, some cannot).

• YES: The D.I. cassette is OK, but continue troubleshooting
• NO: Continue troubleshooting

Does the tach needle bounce when cranking?

• YES: Crank sensor and wiring are OK
• NO: Crank sensor or shielded cable is bad

Can you see trigger pulses with a scope when cranking?

• YES: If no plug cleaning buzz, then D.I. cassette is bad or not enough current to run the unit
  • Check for corrosion in the round connector in the aquarium
    • NOTE: As of mid-November 2001, I doubt this is true.  The schematics don't show the DI power running through this connector, but I haven't had time to check it out first hand.
  • Jumper the three center terminals (30 to 87 and 87b) of the fuel System relay and try it again
• NO: If the tach needle bounces but you don't see trigger signals, the APC/DI ECU is suspect.  Check power and ground.  Disconnect the D.I. connector and have another look (the D.I. could possibly be loading the signals)

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