I had the car tuned last fall by Bryan from Pcmforless. The car was missing by 4700rpm. I didn't have an MSD box and he said that was most likely the problem. Well I installed one and the missing is still there. Any suggestions? It is a new opti spark when I did the engine. Thanks Lee

 

Engine specs? Plug gap? Boost range? Fuel type? etc.

 

D1SC 396, AFR 210 heads, 8:1 compression, plugs gap at .035, aeromotive fuel system, 12 pounds of boost at 4700 rpm on 100 octane gas.

 

plug gap is huge!! i was told to keep my gap between 27-30 but no bigger than 30. you may be blowing your spark out.

 

I'll re gap them at .028. Thanks!!!!!!!!!!

 

I hope the plug gap adjustment works. If not, what valve springs/cam are you using? I've heard of weak valve springs failing to fully close the valves when the combination of high(er) RPM and boost are in effect.

 

When did it start missing, right after the sc install? Maybe the usual suspects such as ICM, Opti?

Hal

 

I talked to my engine guy and seat pressure was 125-130. So I don't believe it is valve springs. I'm leaning toward opti spark but I'm going to re gap plugs first. That's the easiest. Thanks Lee

 

OK I put a set of NGK-10 because I had them. I gapped them at .025. I just took the car for a ride and it appears that the problem is gone. I ran the car up to 6000 and nothing. Thanks guys, Lee

 

Same happened to me when I had my plugs gapped to big. One other thing to think about, would be changing the NGK's out (not good plugs at all according to PCM's for less).

I personally reccomend Autolite.

Glad to hear gapping fixed your problem.

 

Bryan told me to use autolites 103s. What do you run? Projected or non projected? Thanks Lee

 

Bingo. Exactly the plug I've used since 1996 in mine, whether Nitroused or Boosted. Gapped to .035 for me. Never missed a beat.
Nitrous best (100 shot) of 11.1 @ 121 mph full street trim except M/T ET Streets. I haven't raced at the track with the Turbo setup yet .

 

I believe I am also running 103's.

 

TR6's for me w/ no issues whatsoever. I've got a pair of 103's I'm going to try out w/ the next tune up and see if there's any difference between the two. I gap mine to .028