I get pinging on WOT with a JC chip from about 4k RPM and up.
The motor is healthy and runs strong and I burn super (91).
Is this normal for an '85 M30? Im thinking it might be partially due to a restrictive
cat-back. There is a Bosal unit from the cat back, that doesnt look like it could possibly
be more than 1.5" diameter .... %)
Colin
[Edit by Cacatfish on [TIME]1111527012[/TIME]]
Does anybody else get detonation with a JC chip?
Colin,
The Jim C. chip is made for 91 octane, as are most performance chips for the NA E28. The reason you have to run 91 octane is that the ignition timing is advanced too much for regular gas.
However, some people have said they've got no problems -- no pinging, etc -- when running regular fuel with the Jim C. chip, but there are others like you that have problems with the chip even with Premium fuel. You may not notice detonation with a stock chip and 91 octane fuel, but that doesn't mean there's no problem. The advanced spark timing of the Jim C. chip just brings out some problems you may be having with the engine.
My vote is it's definitely not the chip but something with your car. You could be right about the cat. Any other fuel/ignition pieces that aren't new or in known good condition? What spark plug are you running?
The Jim C. chip is made for 91 octane, as are most performance chips for the NA E28. The reason you have to run 91 octane is that the ignition timing is advanced too much for regular gas.
However, some people have said they've got no problems -- no pinging, etc -- when running regular fuel with the Jim C. chip, but there are others like you that have problems with the chip even with Premium fuel. You may not notice detonation with a stock chip and 91 octane fuel, but that doesn't mean there's no problem. The advanced spark timing of the Jim C. chip just brings out some problems you may be having with the engine.
My vote is it's definitely not the chip but something with your car. You could be right about the cat. Any other fuel/ignition pieces that aren't new or in known good condition? What spark plug are you running?
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Seymour in C'ville
- Posts: 360
- Joined: Feb 12, 2006 12:00 PM
- Location: Ivy, Va.
I dont know, I need to take a look at the ignition parts in there. Not sure what plugs are in there either.
I think most of that stuff has been replaced recently, because the guy before me was chasing down a no-start condition (cant remember what it turned out to be) and they went through cap/rotor/wires/ref. sensors and main relay.
The odd thing is how well the motor runs in other ways. It is remarkably fast for an M30, idles great, smogs easy and so on.
Hmmm, one other thought:
What else could cause a weak spark? I do remember checking an intermittent no-spark problem that turned out to be a main relay and the spark didnt seem to be as bright blue as it should be. It was more yellow-whitish. Maybe that is part of it...?
Thanks, Colin
I think most of that stuff has been replaced recently, because the guy before me was chasing down a no-start condition (cant remember what it turned out to be) and they went through cap/rotor/wires/ref. sensors and main relay.
The odd thing is how well the motor runs in other ways. It is remarkably fast for an M30, idles great, smogs easy and so on.
Hmmm, one other thought:
What else could cause a weak spark? I do remember checking an intermittent no-spark problem that turned out to be a main relay and the spark didnt seem to be as bright blue as it should be. It was more yellow-whitish. Maybe that is part of it...?
Thanks, Colin