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Is my car throwing out my tune??

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Old 09-10-2010, 08:09 PM
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Default Is my car throwing out my tune??

for some reason, my car runs fine. then after it is ran for a few minutes, i've noticed that the skip shift, throttle response, and oil pressure all changes. Once it starts acting up, the skip shift comes on. My car starts to hunt when i stop. I got the car tuned and it's fine at idle, it cranks up and goes right at it's idle point when cold. My pcm is just sitting in the engine bay. Could it be a bad pcm? It's been that way since i bought the car. It's like the tune get's ignored after some point when it warms up. HELP!!
Old 09-11-2010, 05:50 AM
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Once warmed up it is in closed loop fueling. Have the tuner log the o2 sensors and coolant temp sensor to see if they are reading correctly. Also, try cleaning the MAF.

Not sure on the oil pressure, you need to give a lot more detail than you have so far.
What car, year, mods, who tuned it, etc. You need to give us info to fix problems.
Old 09-11-2010, 08:35 AM
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Sounds like wiring problems or something. The skip shift coming on, and oil pressure issue, that don't sound like a tune issue.
Old 09-11-2010, 03:44 PM
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i'm thinking the same. I have a 1999 TA with heads, cam, intake, full exhaust, stage 2 t-56, monster 5 clutch, tuned on dynojet with efi live software. The tune is fine imo because tunes don't just go bad. It is also burnt onto the ecu. The oil pressure problem is something i thought was as isolated issue, but it happens the same time as the skip shift activating and the rich fuel smell in the exhaust. I'm willing to bet there is a wiring issue at the pcm. There is a broken wire that is black sleeved and thicker than the other wires. I'm assuming it's the pcm ground. It has been disconnected since i bought the car. Does anybody have pics of what the ground looks like? And is there only one?
Old 09-11-2010, 07:01 PM
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A 99 should have three ground wires bolted to the back of the head.
Old 09-11-2010, 08:25 PM
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The grounds behind the block not being connected wouldn't cause my pcm to fry would it? I'm about to buy another pcm, i don't want to burn that one out as well. The pcm ground only has one right? Does it go to the chassis or to the engine?




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