chevyowner02

I have a problem with the car sitting still in gear it will sit for a few minutes then die. It will start back up fine and it doesn't do it if you leave it in park, it will run all day without dying.
I have scanned it no codes showing. Any Ideals?

Injuneer

Do you have scan software that allows you to observe how the PCM responds with the idle air control (IAC) valve counts when the RPM starts to drop when its in gear? Who tuned it for the cam? Where did they set the idle RPM in gear? ....in park/neutral?

Is this a recent problem, or has it always been problem since the cam install and tune?

chevyowner02

Yea I have been using the Gary Doug software Salomon tuned and it's just a recent problem. I have had the cam in there for about 3 years

JakeRobb

When it dies, does it cut off suddenly? I've heard of BASF torque converter lockup solenoids that engage at the wrong time and cause the engine to stall.

chevyowner02

Yeah it will run 4-5 min in gear then shut off all of a sudden.

Injuneer

It doesn't stumble, or slow down, it just suddenly shuts off?

How did you scan if for codes? The transmission codes don't turn on the SES light.

chevyowner02

No it doesn't stumble or slow down just like you turned the key off. Now I have another problem I have to hold the gas pedal to the floor to get it to start when it dies.

chevyowner02

Finally got around to log it can someone take a look and see if every thing looks normal?
http://www.mediafire.com/view/fjy61q...P1S2106947.csv

Injuneer

Downloaded, try and look at it tomorrow.

Did it stall at any time during this data log? Did it run rough at any time?

chevyowner02

Thanks Fred it did run a little rough but did not stall. Thanks again!
And I did run a scan on it and had no codes on it.

Injuneer

Is the mod info in your signature complete, with regard to the engine?

Based on a very brief look - Something seriously wrong with the Bank 1 O2 sensor readings. The long term fuel trims (LTFT) are dropping well below the normal lower limits of stock programming. The stock programming does not allow the LTFT to drop below 108. That means the PCM can only pull out about 15% of the "normal" fuel delivery. Yours go as low as 80, meaning the PCM is pulling out 37% of the fuel it would normally supply. And then the short term fuel trims (STFT) are pulling out additional fuel.

But this condition is intermittent.... appears and disappears. Who programmed the PCM, and do you know if they altered the LTFT boundary limits? I have never seen anything this extreme before. And, it's only on Bank 1 (drivers side). Bank 2 is erratic, but staying within the normal program limits. In some cells its adding 22% extra fuel, and in some cells its pulling out 12% of the normal fuel.

I haven't looked in detail, but my first step in the analysis is to look for the max, average and min readings in each column of data, which will highlight potential problem areas.

chevyowner02

Yea the signature is correct, except for a CAI I had Solomon do the tune then I sent it back to him, I went to a 3;73 gear. As for the LTFT I have no ideal, do you think I should send him a copy of it and see if he can fix it?

Injuneer

Let me look more closely. I need to find what intermittent condition is causing the Bank 1 problems. Example - could this be the sign of an injector sticking open intermittently? Not saying that's it. Need to spend more time with the file.

Injuneer

Looking in more detail seems to implicate something to do with the Bank 1 O2 sensor.

The PCM enters a fuel correction cell, and the LTFT is near 128. The O2 sensor hangs at readings in the .9xx Volt range. The ECM drops the STFT'S rapidly, pulling the LTFT's down, and the LTFT's bottom out at 80 in many cases. At first I thought this was a problem unique to Cell 18, but that's not the case. Happens in all the cells.

Between the LTFT's and the STFT's, there are instances where the Bank 1 injector pulse widths are only 1/2 of the Bank 2 pulse widths.

When the ECM is not using the LTFT's - open loop and power enrichment mode - there is no evidence that Bank 1 is being fueled any different than Bank 2. In open loop, and in PE mode, the ECM locks the LTFT's and STFT's at 128, both banks have virtually identical injector pulse widths, and the O2 sensors are reading very similarly. Actually, Bank 2 is indicating very slightly richer than Bank 1 in those cases.

There are also two blips in the data, one where the ECM commands a pulse width of 37 mSec on Bank 1, and one where it commands a pulse width of 77 on Bank 2. I'm writing those off as some sort of interference with the data stream.

The Bank 1 O2 sensor seems to work OK under known rich conditions. It seems to respond very slowly to the rapid drop in the STFT's. Not sure if that is a problem with the sensor, voltage leak in the wires, etc.

Again, it is very unusual to allow the LTFT's to drop below 108, and that would be a feature of the program.

chevyowner02

Ok thanks Fred I will start with the wire's and check the volts then move on to the sensor and see if that helps.