Muckman

iTrader: (2)

I just got my car back together and I noticed a misfire at high rpm at 10psi. Im running a brand new OEM distributor with all new components inside, new OEM plug wires with fresh NGK 7s gapped at .032". So I tried gapping them down to 28 and the misfire in boost went away. But now my idle is totally unstable when it was great before (tuned with AEM). I tried another OEM distributor with a brand new coil and it has the same idle problems.

It acts like a bad coil but it can't be as both distributors have brand new OEM coils and both test good according to the service manual. Its not a cam/crank signal problem as Im getting no timing errors.

Idle starts out "OK", but not as good as before, and progressvily gets worse as the car warms up. AFRs start bouncing widely between 17 and 14 AFR, idle rpm oscillates. It starts to backfire and strains to maintain an idle. Worst of all its very easy to stall and it never stalled before. Eventually it's constantly backfiring and I need to add 25% fuel to bring the AFR down to stoich. But when I start it again after its cooled, its pig rich because I had to add so much fuel. It never, NEVER did any of this before. My idle was tuned rock solid before my plugs were gapped smaller.

I noticed when the fan comes on the idle straightens right up and AFR is solid. None of this makes any sense. No other changes were made to the car or tune. It has to be ignition related right? Ive never heard of an ignition unable to maintain spark at idle but handles boost and high rpm fine.

Turbo-charged

T1 cam trigger kit.

i think AEM should start selling this kit with the EMS systems it works so well lol

Muckman

iTrader: (2)

Im probably going to go with the MSD Pro-Billet distributor because I need to be backwards compatible with the stock ecu to pass inspection.

But I still shouldnt have coil problems at idle if boost/high rpm is fine. Idle is childs play.

ghostskinner

check your plug wires

qfast817

check the grounds

Muckman

iTrader: (2)

new grounds, new plugs.
fresh set of 7s gapped at .028"
both grounds from the valve cover and trans are new, both surfaces sanded down
ecu ground on thermastat is ground and resurfaced.
electrical couldnt be better in my car. unmodified engine harness.

JDogg

log t2per, cam-crank and rpms....