SR idles and revs normal, breaks up under throttle

[boost addict]

So at an event this past weekend my car started just randomly breaking up. The car will start just fine, idle, rev in neutral, but when I put it in gear and give it moderate acceleration like normal street driving the AFR's go full rich and the car breaks up. Let off and its fine again. The TPS is fine, Ive already checked it with a meter. Ive also checked the CAS, not sure if I checked it properly but it was getting voltage. My igniter is fine because I swapped it to a buddys car and his drove fine with it. Kinda at a loss here... Going to look at the maf next which is a Z32, but I don't think I can just bench test it since the problem only occurs when the car is actually being driven. The car is on a powerfc. I feel like it has to be ignition related since the car is going full rich when its happening. Any thoughts?

[ultimateirving]

Sounds just like your regular
Boost leak. Especially after hard driving like an event. Go thru and boost leak test your system then Report back.
Start with small things before jumping the gun to fueling or maf issues.

[boost addict]

Everything's tight. No boost leaks here.

[iRONDONkey]

what injectors do you have?

[boost addict]

ID1000's, aeromotive fpr, walbro 255.

[Kingtal0n]

Its a boost leak. An engine wont suddenly go "richer than before" unless the maf suddenly tells the computer "more air than before"


If it was a mis-fire, ignition related issue, your Wideband would be going lean not rich.

Of course there are many other explanations, but they are more convoluted, and often the simplest is the answer.

but just to humor you, some non-simple, unlikely answers are:
-Fuel regulator no longer receiving vacuum signal, or diaphragm torn
-ecu burned up / corrupted
-sabotage :D


Oh I just noticed you have a PFC. It should be pretty easy to see if you have a boost leak, just check the maf watch and see where it is pulling fuel data from.

[iRONDONkey]

ID1000's, aeromotive fpr, walbro 255.

were they bought new?

have you sent them it for a test flow?

[Loomis112]

Boost leak would be my guess. I had the same problem on one of my intercooler couplers and it would start to build and everything would be good until 4k and then it was like there was a rev limiter it would cut and spit at me.


It also idled and revved in neutral just fine.