Marc3.4V6

iTrader: (1)

Finally got a cable to help figure out why my car is always missing, running rough, and occasionally stumbling and dying out of nowhere. It has also fouled or nearly fouled plugs with 20k miles on them, so it's running rich and I have no clue why.

Here is a hotfile link, the forum didnt like the datamaster .uni file.

http://hotfile.com/dl/131825892/a176000/run1.uni.html

for the record the dtc codes are tps low, which I thought I took care of already, the voltage is in the correct range and the other is A/C related and I have ripped the A/C out of this car.

MontecarloDrag

iTrader: (3)

Issues I see:

1- Your TPS is too high at idle, 0.76 Volts (0.8%). You need to set it lower than 0.64 volts and make it read 0% at idle. Idle RPM is higher than commanded, fix that.
2- You have high knock retard, use premium fuel and see if it goes away. Check plugs for correct type, heat range and gap.
3- Correct your A/C issues, pressure and temp, they will make your engine run horrible.

Now that you have the cable, turn off your A/C codes and fix one problem at a time, then log again, reset DTC's and post your results

Marc3.4V6

iTrader: (1)

Hey, Thanks a lot for looking. The TPS thing confuses me because I thought I fixed it because it is higher than spec, as you noted, but the dtc is for TPS low, unless thats a history code that hasn't been cleared. I'm not sure where you saw that the idle is higher than it is tuned for, but it's true, since I got the mail order tune, I had them set it for 750, but it's usually higher.

I always run 91 octane (93 not available here) and plugs are stock heat range/gap ngk tr-55's. With my mild build I didn't think I needed a change in heat range, but maybe I do.

I had no idea that A/C codes can screw with how the engine runs. If I just turn off the code will that fix it, or do I have to run some kind of relay for the a/c sensor? The code probably has never been cleared since I removed ac components (minus the compressor) 2-3 years ago.

MontecarloDrag

iTrader: (3)

On the right side there is a field called Idle RPM, there you see the commanded or "desired" idle RPM. Watch that field from the beggining of your datalog, it starts at 863 RPM and slowly goes down as coolant temperature rises. At the end of datalog commanded idle is 725 but you still have 1000 RPM.

Clear your codes and log again to see if they come back.
What tuning tools do you have?

Yes, you need to disable all A/C codes, they make the engine run poorly because the PCM thinks something is wrong with A/C and tries to prevent a failure.

Marc3.4V6

iTrader: (1)

I have an aldl cable from Moates and datamaster so far.

Marc3.4V6

iTrader: (1)

Here's a couple more with tps reset and all codes cleared. While tightening the tps I thought it was .63, but it must have climbed to .66 while tightening it. MY TB also sticks a bit which I think causes the 0.8% angle. I think the blades are slightly too big, I'll have to take it apart and sand the edges of the blades so they don't stick and then re-adjust the tps. In 'run 4' I had a miss/backfire within the last 30 seconds - 1 minute of driving.

http://hotfile.com/dl/131916283/a66019e/run3.uni.html

http://hotfile.com/dl/131916342/b9ec...drive.uni.html

Marc3.4V6

iTrader: (1)

Someone on another forum thinks I have a possible fuel delivery problem and false knock ( a lot). Any thoughts?

MontecarloDrag

iTrader: (3)

It may be. As I said, check with 91 or higher octane. If knock doesn't go away check fueling. All cases I had with knock retard at idle were false, but you need to be cautious.

Your TPS must be 0% at idle, period. If it isn't then something is wrong. Adjust what you need to make it 0% and volts below 0.64

Hook a fuel pressure gauge and fix it to the hood so you can watch it while you drive. Take the car for a ride and watch if the fuel pressure drops at the same time it missfires/backfires.