blown 944

sounds like too much fuel. Have you checked the FPR and the dampner to see if the diaprams are leaking into the signal lines? The NB afr gauge will show very lean if the mixture is extremely rich.

Black51

Just to make sure here, so we're not all wasting our time on this one, you didn't just happen to fart whilst driving an n/a, right?

TheDice951

Yes I did check the regulator and dampener. The gauge rich while under WOT. The boost reads 12lbs during WOT, the boost is measured at the manifold. I checked for boost leaks. I checked fuel pressure and did leak down. If I slowly press the gas the car may hesitate a little through the rpms but will go passed "the wall" but still doesn't feel the same. It also hesitates/stumbles under normal driving sometimes too, like pulling away from a stop sign. The turbo also spools up the same and at the same time it just feels like the engine freaks out and doesn't know what to do with the extra air... I'm leaning more towards a sensor or the tune... I am not sure if it a possibility that the computer could get screwed up in mid pull but that's what I'm left with.... What sensors could cause this? I replaced the O2 and TPS..

blown 944

I'm not sure if it will apply here at all, but I have had a DME temp sensor fail and cause the car to run very erratic in the past. They are very inexpensive.

Tedro951

It doesn't explain the lean AFR, but I'd change the plugs. You've mentioned they look good, but you also mentioned the symptoms include rough idle.

If the rough idle came on with all of the other symptoms, I'd consider every suggestion about wastegates and exhaust as irrelevant.

I'd change the plugs that you mention "look good". I'd also get a cheap harbor freight thermometer and see if one of the header pipes is colder than the others at idle.

Spark has a hard time jumping the gap at increased cyl pressures. It will jump out of the circuit at any point in the system that has an easier path to ground. It might help to rev the engine in the dark. Look for a spark anywhere its jumping out.

Keep on it, and you'll get it fixed.

black944 turbo

What did you change prior to this happening? I had a chip tuned by a reputable vender (very expensive and will remain unnamed) that did very similar symptons. Now mine was a custom tune for a maf and I got so fed up with it that I ripped it all out and went back stock and guess what it is fine and has been for a long time now. If you just changed the chip this is another place to look.

How do you boost leak test the car?

TheDice951

lol, what did i change? the muffler.... 2 days before this happening.

the old muffler is back on because i didnt like the sound of the race muffler

i made a leak tester with parts from lowes and an air compressor... i put it on the inlet of the turbo and but 20psi in it and no leaks so uped it to 40psi and still nothing so i think im good there.... GOOD SEAL!! lol

hansman

I am gonna bet on too much fuel
Do you know exactly how much fpr you are running at the rail
funny thing everyone thinks turn everything up and all is well but too much fuel lowers the boost

anyway think of the bright side you will have checked practically everything on that car!

black944 turbo

Hey Dice, I am glad you found no leaks, but putting more than 10 psi through your system is risky at best.

JFreeman

Where are you located? Maybe try swapping your computers out with some know good ones, just to rule them out. Or i wonder if the coil is getting weak, does anyone know a good way to test it?

schip43

You can check the primary and secondary windings with a DVOM but a bad coil doesn't make a funny sound.

TheDice951

hansman, i didn't touch anything, so i have been running the same settings for the last year. the psi at the rail is 35-40 at idle

black944 turbo, i know it was risky but i was getting sick of chasing a ghost so i went a bit crazy... lol

jfreeman, i live near Raleigh NC. i don't know anyone that has roughly the same mods to swap computers. i really dont know many Porsche people around here.... the ones i do know have mild mods

i am leaning towards a sensor... one day it runs awesome w/ out boost and the next it runs terrible. if its colder out it runs awesome too. no matter the conditions though, it runs ****ty under boost...

Josh B

Is your fuel pressure regulator adjustable or just a set 3 bar bosch unit?

I would highly recommend investing in a Zeitronix wideband. You can add sensors onto it and monitor fuel pressure and boost and EGT as well plus log them on a computer for closer analysis.

black944 turbo

Dice, if you find your way down towards Charlotte, I am willing to look it over with you.

TheDice951

josh b, its an adj. Huntley unit.... i will look into that wide-band

black944 turbo, thanks, i will let you know if we head that way. pm me your number

for everyone, i was almost out of gas yesterday, and filled it up at the same gas station i always go to. i put 93 octane in. the car seemed to run a bit better even under boost? still stumbles a little but actually pulls... i don't know if it would be possible for a gas station to have had bad gas for the last month and a half but that's what it seems like.... its probably coincidence that it runs better after gas.... the problem gremlin is taunting me!!!