Help Deciphering Datamaster .uni file - Car Dies while driving
04-25-2012, 06:49 PM
#1
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Car: 1991 Pontiac Trans Am
Engine: 305 TPI 5.0L
Transmission: 700R4
Axle/Gears: 2.73
Help Deciphering Datamaster .uni file - Car Dies while driving
Need some help here deciphering some data I took during a break-down: Car drives fine for about 15-20 minutes and then all of a sudden it bogs down during acceleration at about 25 MPH, back fires, and dies. I can start it just fine, idles OK in P and D, but when I accelerate it craps out. If I wait a few hours its fine again, but will die again within 15-20 minutes. Weird.
I recorded this event with data master and was wondering if someone could help me figure out what caused the car to die. There are a few flags that look important at the time for this event:
1) The EGR DC is at 100 until the event, then it gradually lowers all the way to 0.
2) The CCP DC is at 0 up until the event, and then it shoots up to about 50 during the event, and then back to zero.
3) The Fuel Trim is at 4 before the event, and then goes haywire during the event changing to 11, 6, 5, 9, etc.
4) Spark retard is 0 up until the event, then it blips to 5.8 and back to 0.
I just had a Flowmaster American Thunder cat-back put on, and replaced cap, rotor, and coil. This issue has only been happening after these were installed.
I have the .uni file if anyone wants me to email it to them, the forum won't let me post it up.
Thanks for any help!
I recorded this event with data master and was wondering if someone could help me figure out what caused the car to die. There are a few flags that look important at the time for this event:
1) The EGR DC is at 100 until the event, then it gradually lowers all the way to 0.
2) The CCP DC is at 0 up until the event, and then it shoots up to about 50 during the event, and then back to zero.
3) The Fuel Trim is at 4 before the event, and then goes haywire during the event changing to 11, 6, 5, 9, etc.
4) Spark retard is 0 up until the event, then it blips to 5.8 and back to 0.
I just had a Flowmaster American Thunder cat-back put on, and replaced cap, rotor, and coil. This issue has only been happening after these were installed.
I have the .uni file if anyone wants me to email it to them, the forum won't let me post it up.
Thanks for any help!
04-26-2012, 02:06 PM
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Re: Help Deciphering Datamaster .uni file - Car Dies while driving
It sounds like the ECM is bad. Do a tap test on it and see if the scanned items change or how the engine running changes as the ECM is tapped on.
RBob.
RBob.
04-26-2012, 05:14 PM
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Car: 1991 Pontiac Trans Am
Engine: 305 TPI 5.0L
Transmission: 700R4
Axle/Gears: 2.73
Re: Help Deciphering Datamaster .uni file - Car Dies while driving
You mean literally tapping on it? I changed the ECM a few weeks ago, but I suppose the new one I got from Car Quest could be crap.
04-29-2012, 07:23 AM
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Car: 86 Monte SS (730,$8D,G3,AP,4K,S_V4)
Engine: 406 Hyd Roller 236/242
Transmission: 700R4 HomeBrew, 2.4K stall
Axle/Gears: 3:73 Posi, 7.5 Soon to break
Re: Help Deciphering Datamaster .uni file - Car Dies while driving
It appears that your ignition turned off.
The ECM "Ignition volts" (Pin A6) and fuel Pump volt" (Pin E13) both go to zero at that 3:49 time.
But...
The ECM is still adjusting the Idle Air Control and logging data so all power did not go away.
Check ignition switch and or power fuses/wiring.
The ECM "Ignition volts" (Pin A6) and fuel Pump volt" (Pin E13) both go to zero at that 3:49 time.
But...
The ECM is still adjusting the Idle Air Control and logging data so all power did not go away.
Check ignition switch and or power fuses/wiring.
04-29-2012, 10:27 AM
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Re: Help Deciphering Datamaster .uni file - Car Dies while driving
RBob.
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