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!

 

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.

 

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.

 

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.

 

Yes, tapping or rapping on the case with your knuckles or the handle of a screwdriver. Many of the '7165 & '7730 ECMs fail be going intermittent.

RBob.