I have searched the forums , but have yet to find an answer. To give you the whole story, when I was driving the car home after purchasing it, a boost hose failed that connects to the wastegate. It was dry rotted from running near the downpipe and there was a huge hole in it. Anyway, when I boosted the car, my gauge read 2lbs (which was wrong because it tied into the same boost line that failed) but the car overboosted and a very loud missfire happened. I've fixed the boost hose. Now the car will missfire mildly at 11lbs and get alot worse as you increase boost. At 10lbs and below the car runs smooth with no issues. The previous owner claims he was running 14lbs with no issue and when I test drove the car, it was set to 14 lbs. My car also seems to be running pretty rich. I hope I wasn't too confusing with my description, but if anyone has any suggestions as to what the problem is it would be greatly appreciated.

Thanks

 

Oh, I guess I should mention I'm running a T-88 single with an upgraded fuel system and MSD ignition. I know it sounds like I just need a tune, but I'm wondering if something might have gotten damaged when the car overboosted and misfired. It was a VERY loud pop. I don't think I blew the apex seals or anything that bad because it runs almost perfect at 10lbs.

Thanks again.

 

Not really sure what your problem is, but did you mean backfire?

 

Most likely rich misfire. Get it tuned using a wideband and someone who knows how to use it.

 

...yeah...misfires aren't loud, means didn't fire...no combustion..

...backfires are from unburned gas in exhaust igniting or timing too retard and plug firing during exhaust cycle.

...my guess is that you are actually running too lean from a vacuum leak at high boost and what you think is a "loud misfire" is actually a backfire of unburned gas in the exhaust from a lean misfire.

...I'd check this first cuz pre-ignition at high boost is a rotary killer.