1127/1129 Codes on 3.4L

[tholyoak]

OK I've had a nagging issue on the 3.4 I stuck in my boxster

see http://www.renntech.org/forums/inde...wtopic=4798&hl=

for details on the swap

Some details

1) the DME was reprogrammed by Imagine Auto

2) the car has supersprint headers and muffler with dansk cats for a 3.2

OK, since doing the swap I had an 1123/1125 error, I assumed it was a bad MAF and bought a new one since the old one had ~70k miles on it

Swapped in the new MAF and now I have 1127/1129 error and some part throttle driveability issues, with the 1123/1125 error it was just an idle problem although it did seem to hicup at around 6800 rpm or so at full throttle.

With the 1127/29 light on, the long range fuel trim is maxed at -32 the pre cat O2 sensors seem to dither properly in range but the post cat sensors also seem to fluctuate out of range, the load signal is at 2% which is too high, the MAF #/min seems in spec but maybe a bit high.

Factory manual says possible fuel pressure or stuck injector problem.

The fuel pressure is fine and I don't think it is a stuck injector problem as it is affecting both sides.

Anyone have an idea? Perhaps the new MAF is bad as well??

Could the Dansk cats not be working as well as they should ?

There is a bit of an exhaust leak at the U-pipe from the cat to the muffler, that i need to fix since the ID of the Dansk cats is smaller than the Supersprint muffler U-pipes. This would cause a lean problem though not rich right.

The oil filler tube has been updated with the correct part.

I think that is all the details.

Maybe I should just drive it over to Imagine and get it on the dyno.

Thanks for any help.

Todd

[Loren]

Sounds like not enough air -

DME 5.2.2 right?

Did you use the C2 throttle body or the C4 eGas throttle body?

If you clear the codes and disconnect the MAF the car should run mostly fine and you will get a MAF code (P0101 I think). Then see if you still get other codes.

[tholyoak]

Loren,

Yep 5.2.2 DME, it is the cable throttle body that came with the 3.4L engine.

Car is also running a EVO intake kit for an S that was modified with an aluminum 3.5" pipe section to work with the 996 engine. I got the same codes before the EVO install as I do now with the evo in place.

I did disconnect the MAF and drive around, didn't get the 1123/1125/1127/1129 codes, I did get a MAF code and an intake temp code if I remember correctly. Maybe I should do it again and see.

Perhaps the DME program done by Imagine (GIAC dealer) is adding too much fuel??

Todd

[Loren]

Yeah, you are right I forgot about the intake temp code - normal with the MAF disconnected.

Did you get the right MAF sensor? Should be a 996.606.123.00 (can't find the Bosch number right now...)

[tholyoak]

Yeah, that was the first thing I checked when I swapped in the new MAF and got the check engine light, bosch part # 0280217007. I didn't get it from the dealer so it doesn't have the porsche part #.

Todd

[tholyoak]

Any other thoughts? Should I just take my chances and shell out for another MAF sensor?

Todd

[Loren]

Well, at this point I would say it is either the MAF or the DME program...

[tholyoak]

Found some time to look into this a bit more. Yes I am cheap and trying to avoid buying another new MAF if the one I have is fine. Per the factory manual I tested the MAF,

there is 5V between pin 47 and pin 45 and battery voltage to pin2. The manual says there should be 1V between pin 17 and 45, with the old MAF that has ~80k on it shows 1V. This sensor gives 1123 and 1125 errors and was the reason I bought a new sensor. The new sensor that gives the 1127/1129 codes shows 0.95 V. So does this suggest that the new sensor is bad? The factory doesn't give any +/- tolerance so I assume it is bad.

Todd

Edited February 16, 2006 by tholyoak