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92 Cavalier ICM question

Discussion in 'Chevy Trucks' started by 70monte, Jan 5, 2009.

  1. 70monte

    70monte Senior Member
    Messages: 468

    I know this is a truck forum but I was wondering if someone can answer an ICM question? Can a loose spark plug cause damage to an ICM, coils, CPS or plug wire?

    A few weeks ago my 92 Cavalier started to miss occasionally on a short trip. I found out that #1 spark plug was loose in the head. I tightened it and the car ran good initionally. But since then the car has started running worse and feels like it occasionally misses. I replaced the plugs but that didn't help. Gas mileage has gone down No SES light and no codes stored. The ICM and coils were replaced last year with new AC-Delco parts as well as the CPS. O2 sensor is fairly new. The spark advance at idle is only 6 degrees vs the 18 degrees the service manual says it should be at as well as the air/fuel ratio is at 14.6 vs the 14.7 it should be at.

    So, can a loose spark plug cause damage to other ignition parts and could any of these affect the spark advance? Thanks.

    Wayne
     
  2. Spitz

    Spitz Senior Member
    Messages: 192

    Spray water on the plug wires and anything ignition related and see if you see secondary voltage jumping out from anything, any stray voltage and you need to look into replacing secondary ignition pieces.
     
  3. 70monte

    70monte Senior Member
    Messages: 468

    Thanks for the info.

    Wayne
     
  4. Newdude

    Newdude Senior Member
    Messages: 878

    Curious, did you change the spark advance or was it like that??
     
  5. 70monte

    70monte Senior Member
    Messages: 468

    No I didn't change it and was wondering why it was wrong. This car has no distributor, just two coils sitting on the ICM. I'm not sure what controls the spark advance on this car other than the ECM but I don't know what sensor or component it would get its info from. Sometimes I wish they would have never installed computer controlled components on vehicles. It was so much simpler in the old days.

    Wayne
     
  6. KSikkema

    KSikkema Senior Member
    Messages: 179

    you will not be able to do anything about the timing. it is all computer controlled and non adjustable. it is referenced off of the crank position sensor. a loose plug will not affect your timing and should not affect any other ignition components unless that plug is misfiring so badly as to cause damage to a coil because it can't ground anywhere. 14.6 on the air fuel ratio is so close that i wouldn't worry about trying to get it any closer to 14.7. remember, that is only scan data and a generated number. there is nothing actually measuring that precisely. it is only a general indicator. i would check the plug wires as previously posted. that's a good place to start. have also seen on those early 2.2s a defective egr cause a misfire driving down the road.
     
  7. MAR4CARS

    MAR4CARS Senior Member
    Messages: 246

    Chances are when you removed the plug wire to tighten the plug the wire got broken internally.Not to mention those cars go through plug wires as the routing of the wires on those cars gives them lots of points to be able to short out.
     
  8. 70monte

    70monte Senior Member
    Messages: 468

    Guys, thanks for the information. I will go ahead and change the plug wires. They have about 45,000 miles on them. They are Carquest wires. Does anyone have a recommendation on some better ones? AC-Delco maybe?

    I have another EGR I can try that came off the original motor of my other 92 Cavalier. It has about 103,000 miles on it. Thanks again.

    Wayne