Car stalls when clutch is engaged or sometimes when car stops
10-01-2010, 08:39 PM
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Car stalls when clutch is engaged or sometimes when car stops I have a 1999 Trans Am w/ h/c/i/e and a efilive tune. This car has gotten so many new parts trying to fix this issue. I replaced the fuel filter and pump and it drove great for a little while. Then it started to drop @ idle just a little after letting off the gas. Now, it is back to it's original self and it stalled on me at a busy 4-way intersection last night. That's the last straw! This is not working out with a baby due in 2 months. I have no codes, so what in the hell is it? I have a 99 Z28 pcm to replace the one I have because For some reason it's like my car loses it's tune after a short while of driving. Skip shift comes back on (it was tuned out) and the fuel mixture turns rich because i can smell it. Does anyone have pics of how the pcm ground is routed and where they are? I will try to do it myself. Any help appreciated. Is this a fried pcm or what?
10-02-2010, 01:12 PM
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A PCM can't "lose" its tune... what can happen is that exhaust leaks cause the O2 sensors to see entrained air and feedback to the PCM that the car is lean when it really isn't... then unneeded fuel is added causing it to run rich.
Was the car properly tuned in open loop with a wideband to start with? Does it run better in open loop and slowly get worse when put in close loop?
Was the car properly tuned in open loop with a wideband to start with? Does it run better in open loop and slowly get worse when put in close loop?
10-02-2010, 06:43 PM
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i believe so. When i start it up, it would run fine. as it warms up (goes to closed loop), it starts to hesitate more when coming to a stop and the rpm returns to idle. the car wasn't tuned with a wideband because i never had a wideband installed, the guy never even went under the car for anything. I don't know if he had some preset parameters or he guestimated, but he just hooked up the laptop up and ran it about 17 times to get the tune done right. I got a wideband put in by another tuner here where i moved so he could read it on his mustang dyno
10-03-2010, 12:32 AM
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lol, i was attempting to put my pcm back in and while doing so my car just shut off. it would not act up at all while i was playing with the idle & clutch in the garage. But i now have to see what caused my power to shut off. it wasn't a hesitate then stall, it shut off completely. I would hate to have to get another tune and it not be the issue.
10-03-2010, 10:11 PM
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ok, i sat in my car and tried to record the car cutting off at idle. I tried to record it stalling with light throttle pressure. It actually did stall on me once but it was before i decided to record it. But since then it drove fine. I tried to drive at 1300 rom with a torquer v3 cam and it wouldn't stall with the clutch in. That pisses me off. So now I have a p0107 code. I just recently changed map sensors as an attempt to troubleshoot. I don't see how I couldn't push a sensor into a whole correctly. So is there anyway it's affecting the pcm because it wasn't on when the car was tuned?
