Hardcore tech help plz

[twistedtech]

I had the car back in on Thursday the 18th, and let me tell you. This car goes against all I know and all I have been tought. My dad is even askin me wha tthe hell is going on because he has never seen one beat me. it does not matter what test you run or what circut you dicect. The results are the same EVERYTIME. What is in this circut that will tell the pcm that the dpfe is on full tilt? I have checked all the pieces on this engine with the MT2500 and all seem fine. Now with that being said I think the connection at the pcm was a little loose and that is what caused all the codes last go round. I did recheck that last week when it was in and he said the car ran great for the week and the codes were not there this time. No matter what you do, what you check or how you hold your tounge, the readings are the same.

[shorod]

Well, you're probably not looking for something that is telling the PCM that the DPFE is at "full tilt" since you get the same readings even with the DPFE disonnected. You're seeing the 5.02V on the signal line from the DPFE when the DPFE is out of circuit. So, unless the PCM incorporates a pull-up resistor inside the PCM, I would expect that this line would read lower.

Next fun test, install a test light from the PCM lead for signal from DPFE to ground, now measure the voltage on the signal input to of the PCM. Are you still measuring 5.02V, or something considerably smaller? If you see virtually no voltage, then there is probably a pull-up resistor in the PCM. If the voltage is nearly 5V, then it would seem there is a short to Vref somewhere in the circuit. This seems unlikely since you've had another PCM in stalled, but still worth checking.

-Rod

[twistedtech]

"Next fun test, install a test light from the PCM lead for signal from DPFE to ground, now measure the voltage on the signal input to of the PCM."

OK lets get 1 thing straight right out of the gate,YOUR the only 1 having fun,next,been there done that. I just don't get this at all.

[shorod]

Originally Posted by twistedtech

"Next fun test, install a test light from the PCM lead for signal from DPFE to ground, now measure the voltage on the signal input to of the PCM."

...been there done that. I just don't get this at all.

So what did you measure for voltage with the test light installed?

-Rod

[twistedtech]

This has to be the most dumbazz post I have ever typed. Not once in 23 years have I EVER once said this in a serious fashion,allways joked about it but never belived it. THE CAR FIXED ITSELF! I crap you not. The kid came in with the car and said the light was out, I grabbed the scanner and hooked it up, sure as shit it worked fine. I'm not even sure I want to know.This is just fugged up.

[shorod]

As I'm sure you realize, this stinks of intermittant connection. How humid or wet is it where you're at?

-Rod

[twistedtech]

The F.P.O.S. is back. Surprise! I have to lean to a sour connection at SOME point. As for wheather, I am in south eastern Ontario, so at this time of year it is all over the place but this started back in Jan if I recall right. Total winter at that point. Without going back to look I think I asked once what else is in line with this thing to make it go so high. Make car go from red to black, make car stink like smoke, make problem go away. I now have a new thing on my HATE list.