I'll start off with my setup.
450cc injectors, VAFC with -38 fuel cut throughout the high throttle, Walbro 255lph intank pump, Tial Wwastegate at 8psi, B&M FPR, and a Garrett T3/T04e 57 trim w/ .63 A/R turbine.

I'm having a really bad problem with the car missing under boost around 5500-8200. I got brand new NGK pulgs and wires and that didnt solve the problem. The car will run perfect if you just have say 50% throttle and take it to redline, but when its close to WOT it misses.
I'm aware that the B&M cant return enough fuel with a Walbro and the stock bottom end and I'm getting that problem where the idle pressure is at 42psi (and it idles kinda rough and backfires sometimes when reving in neutral) and it doesnt change more than 2psi when I pull the vacuume line off.

Also interestingly enough sometimes the car will work perfect and pull hard as ---- through 1st and 2nd gears, but then at 3rd it'll pop and miss.

Any ideas? I'm going to throw the AEM on today since it's a 1:1 so maybe that'll solve the problem, but I'm kinda in the dark on this since my buddies havent seen this before in a car.

Thanks

 

Sounds like a timing problem, one way to do this isnt a smart way but it usually works, when your car is cold, boost, see if it boosts just fine when cold, and if it does then it wont when its warm, its your timing, the boost really messes with the car when its not timed perfectly, good luck -Ben

 

It sounds to me like you are running really rich. You do have a a/f guage right? Try leaning it out with the fpr a little.

 

could be too rich, or could be the same problem i was having before i was boosting.. when i would go WOT at about 5500-7800 it would sputter and pop like your explaining here. it was my distributor cap. MSD pro caps are garbage. ive went through two of them now, so im going back to the stock one. try pulling your cap off and checking the prongs and see if they have corrosion/green ---- on them. if i cleaned mine it would fix it for a little while then it would do it again.

 

i am having somewhat the same problem and my BTM is on 0, when i'm at WOT and turn the **** it feels like i'm being held back even more. my timing belt is going to ---- though so i will see if that fixes my prob.

 

Its timing.My crx did the same thing even with the full msd i had on it.Advanced it a few degrees and it ran great after that.

 

Are you running an Intercooler? If not it sounds like the air-fuel mixture is getting too hot which in turn is pre-detonation and if thats the case then you need to turn your boost down or use 105 octane gas. OR run an intercooler