FNWY2004

Hello,

I recently had a gearbox replaced in my 997 Cup. Received the car back from the shop running fine on, and off the trailer. While running the car on Jack stands to do a KMP paddle shifter gearbox adaptation, I also reset the throttle sensor via the steering wheel buttons. This is where all the idle problems started.

Now when I start the car it runs very rough and pops and bangs through the intake and exhaust. It idles anywhere from 850-2000 RPM with a surge. 3000-6000 rpm and the car smooths out and sounds great. Modas gave me both lambda codes. Changed 02 sensors. Problem still exists. Pulled all the spark plugs. The left bank seems to be running rich (black and sooty). The right bank looks fine. It seems to be dumping excess fuel into the headers. Spark plugs and coils are brand new. Fuel filter was just replaced. Resetting the codes via modas seems to clear the idle issue for a few seconds, but as soon as the engine pops at low idle both lambda codes come back.

anyone run into an issue after doing a throttle reset on a cup? I’m stumped here.

Also, if anyone has Modas files 311P3C2T could you email it to me at aaronwalker_430@hotmail.com please? The file I have works, but it’s just labeled 09 Cup. Not sure if it’s actually the 100% right file.

Any thoughts or pointing me in the right direction would be greatly appreciated.

One thing that I failed to mention is that the engine was rebuilt by Autometrics before the PO bought the car. It’s been built to 4.0 liter. Is it possible that there was a non factory tune in the Bosch ECU, and the throttle reset messed with the fuel/air maps?

claykos

Call Gordon at Autometrics. He is top notch and especially if he did the motor should be able to help.

FNWY2004

Thanks! I reached out, but then figured out the error in my ways. The car has a KMP throttle body bracket on it. The way that it was setup on the car, it held the throttle open by about 1/16” while following the book procedure for throttle reset. This small opening translated into a 30% deviation for the throttle position voltage in Modas. Had to make a small adjustment to the throttle actuator, then reset. Problem solved.

Moral of the story, stop screwing with things and just drive the car!

Oddjob

I get similar lambda sensor faults constantly. I believe its for lean conditions, and I think it's usually at lower rpm, lower throttle positions, occurs often when idling. Had a shop look at it, and with the car running they felt the O2 sensors were responding correctly. Not sure how much information I can determine from the info screens.

FNWY2004

try the throttle reset. You may be experiencing what happened to me after I reset with the throttle slightly cracked open. Make sure the throttle is fully closed when you do the reset. You shouldn’t be throwing lambda codes at idle.