I just got the car back together with the LTCC, new wires, plugs and new valve springs. It still misses at high rpm, what are the odds of have a bad opti? It has 30k miles and is about 3 years old?

Does anyone have experience with this sort of thing??

thanks a bunch, I'm supposed to head out for the Power Tour Thursday!!

 

Hey Brady,
Is this under load, or stopped and reving, or both?

And have any kinds of logs by chance?

 

prolly already checked into to but,brady its possible your blowing out the spark under boost..

 

It misses under load, it doesn't appear to do it when I just rev it freely. It doesn't just miss slightly either, it breaks up badly. It might have a miss below 3k too, but it's hard to tell if it's got a random misfire or if it's just the cam talking..

I don't think it's blowing the spark out, I have new autolite 103's gapped @ .028

 

you read the plugs after its done it? could be mistaking a bad miss for detonation..plugs will tell the story... then again diagnosis over the internet is a crap shoot ...so I'm just throwing out ideas you may or may not have checked into..

 

Maybe one of your new coils is bad, I'd test them, and the plug's resistances too.

 

Don't have much experience (ok, none) with boost, but... that gap seems awfully small, even for high boost.

Maybe it's breaking up/missing because the spark isn't "big" enough to fully ignite the mixture. An odd thought, but maybe you could try upping the gap to ~.035 and see what happens?

 

Thanks for the ideas, today I swapped out the opti for a known good opti and it helped drastically. My old opti sounded like it had rocks in it. I still have a miss though, but it *seems* like it may be a single cylinder miss rather than random misfire. I'm going to pull a couple coils off my '98 and throw them in the car along with the LT1 coil, and head out on the Power Tour.. F*ck it, if it breaks down, I have a trailer

wish me luck!
....Brady

 

Brady I had a similar problem. Did you check to see if the LTCC is pulling any codes? If any spark plug wires are close to the opti wires it will cause a miss. I had to move all plug wires atleast 3in from the opti before it cleared my problem.

Good luck

 

Yeah check to see if you're pulling codes on the LTCC, could very well be your opti harness.