View Full Version : fuel cut VS ign cut VS boost leak ?

06-15-2005, 06:48 PM
ok, i have a little situation. My car ran perfectly fine before. Just a few days ago, im expiriencing some type of cut. I figure it is a fuel cut, but im running stock everything so it dosnt make any sense. I'm only runing 7psi, Walbro 255 pump, and Z32 filter. I did some more runs on the highway just now and i've observed this only happens in high RPMs and full boost. It happens anywhere from 4000RPM to redline on full boost so it makes sense to me that its some type of fuel cut. Whats wierd is there is no other symptoms. I dont have idling problems, i dont have stalling out problems, i dont have any hesitation, spuddering, or studdering. Anyone have any ideas? i am stumped. Oh yea, it might possibly be a boost leak or an ign cut, but im leaning more towards this being a fuel cut problem because i dont notice any extra backfire or huge fireballs after my loss of power. I did some searching and most ppl who have identical problem with me ususally have their cars spudder or have crazy idle or something. Mine dosn't seem to do anything else at all.

06-15-2005, 07:31 PM
I vote boost leak. Make a home made tester. You'll be suprised at what you find.

06-15-2005, 08:02 PM
i thought so too but it holds full boost fine until higher RPM.. the boost stays the same so it dosnt make any sense for it to only leak in hgh RPM. and dosnt it ususally studder when theres a boost leak?

06-24-2005, 12:52 PM
im still having problem. I regapped spark plugs and everything. How can you tell missfire? Does it just buck or what?

06-24-2005, 01:17 PM
Misfire you can feel in the pedal if you know what to look for, depending on how bad it is, it will buck if its bad enough but I would say boost leak still! I had 6 boost leaks and it still held constand boost at 1.2bar, just cause it holds boost doesn't mean there is no leaks! Pull the plugs and see what they look like! I bet they are nice and black!