so this is an issue that i’ve had a few times over the past month or so, but usually it lasts 30 seconds and stops…i can have my foot WOT but it’ll go on and off and slowing rev itself up…driving’s a bitch, jerks back and forth with the fuel randomly turning on and off…
got so bad last night that it bogged itself all the way down, and stalled…and wouldn’t even start. i turned it completely off, turned off the turbo timer, waited a second, and then it started, but was really bad again…and had to pretty much floor it for it to build up rpm’s enough to take off, and make it the rest of the way down my street…
Brand new EFI harness, so it’s not a wiring problem…had vacuum system checked for leaks not too long ago, and it was fine…and besides, if it was a vacuum problem, it would be all the time, not every other week for 30 seconds (except for the past 24 hours, when it’s been pretty regularly bad…)
hopefully eric (blk300tt) still has his old O2 sensors that were recently changed, though the old ones worked just fine…and i’ll change mine with his old ones…see if that works…
MAF isn’t loose, and i dont think it’s bad…again though, that would cause this problem to always occur i think, not just every now and then…
just got a new(er) TT fuel pump last fall, so doubt that’s the problem…
i’m open to all and any other suggestions while trying to diagnose the cause of the problem…
sounds like a safety thing going on in the computer. im wondering whats causing this because the reason it has to be doing it would be thinking the car is too lean or over-boosting. and with the o2 sensor or MAF being a possible problem…those WOULDNT make it an all-the-time problem…in closed loop operation (non-wot) the computer generally uses signals from BOTH the maf and the 02 sensor, but in OPEN loop, it reads ONLY the the maf. so if your getting fuel cut at WOT, it would seem to me its a maf issue. that or the throttle positioning sensor might be bad and the car might be THINKING its not at WOT when it is and then the computer is reading over 100% load and therefore cutting fuel until load is back where its “supposed” to be.
sorry for all the tunning giberish
these are all reasons i experienced the same problem…which im experiencing yet again. this time i think its plugs though, the maf and tps are both brand new, and im not getting a CEL in relation to the o2. i have to datalog and see whats going on once i get my wideband up and running again.
hmm… know anyone with a spare ignitor laying around? i HIGHLY doubt its your o2 sensors, they wouldn’t kill the car like that. is it real violent like fuel cut, or more of a hesitation?
^ if that be the case you can either replace them or go out on a limb and take them out, and clean the living shot out of them with some injector cleaner.
Like focusinprogress said, o2 sensors are usually not used by the ECU at WOT. MAF/MAP or ignition would be prime suspects to me. Althouhg you’d think ignition problems would’ve showed up at any throttle position.
had to buy a different PTU when doing the swap, and newman had to do some fancy wiring from what i remember to make it work because my old one was shot…
i’ve come to the conclusion tonight that it has to be a spark issue, because i’m getting backfire big time when i coast in gear, or down shift…or even when i try to go sometimes…
the car doesn’t just do this at WOT, it does it steadily…skunk heard it tonight…
the car wouldn’t be backfiring so loud/frequently unless it was getting fuel…and it wouldn’t be backfiring if the fuel wasn’t getting dumped into the exhaust, rather than getting spark…is my logic correct here? could it just be PTU problems causing spark loss? at times it’s almost methodically (sp?) misfiring…like feels as if every other cylinder is firing…i’m gonna clean out the connections and check all the wiring by the PTU probably tomorrow or thursday…i’ll prob also pull the coil packs to make sure they’re all still in good shape, and the coil pack clips from the harness, etc…
just gonna be so damn hard to see if i fix the problem because it’s only occuring every now and then…and there’s no real set situation that causes it to stat up again…it’s completely random…i haven’t noticed any pattern as to when it usually starts to act up…i’ll just have to try cleaning out the connections and making sure everything is connected and snug tomorrow, and wait and see if the problem comes back
