3.2 Conversion ECU

[CidTito]

My car went to the 3.2L to 901 Transmission over seven years ago. However, while the some of it has been smooth, I need a little bit help on the other .

My car tends to end up frying the ecu.

- it has a replaced wiring harness, grounds check on my car, new voltage regulator and all injectors work.

It will fry with the following steps. I am at a loss what to fix.

1. Bring car up to temperature, drive for a long distance
2. Shut car off for 10 minutes or so.
3. Start car, drive for a second long distance, but bring back to temperature
4. Shut car off again for 10 minutes
5. Start car, drive for short distance enough to bring car to temperature
6. Shut car off for a third time.. let car cool for another 10 minutes
7. Start car
Results... (1) hesitation issues in performance or (2) no start.. ecu fries (intermittent)

this ecu has been worked on over and over... but its fried like 5 times... its being rebuilt now
What might be the best way to retest my car before plugging this fixed one back in.

[CidTito]

>1969 911T with a 1988 3.2L engine.

What is the best way to troubleshoot my car without the ecu in my car?

1.) what is the best way to troubleshoot before the ecu goes in?
2.) what is the best way to troubleshoot after the ecu goes in?


Tito

[edmayo]

What do the people rebuilding the ECU think?

[Dezzmo]

You can also check with a friend of mine over on Pelican named Sal Carceller "scarceller".

He knows these ECU's very well and should be able to pinpoint the problem for you.

[911quest]

I assume you had to switch some wires around on the 14pin connector to match up with 3.2 harness is it possible you might have an issue there? The trick might be to find out what there doing to the DME to fix it.

[ESully]

I would think that after all these rebuilds, whoever has done the work would have a suggestion by now as to the problem. Perhaps it is time to use someone else. I would think that a knowledgeable person would be able to tell you what part of the DME circuitry is being affected, and the components that would lead to this failure.
I had a succesful transplant in mine for a few years and I can only think of a few areas that might cause issues. It is possible for an injector to cause problems only under certain conditions, and behave properly till put under heavy load. They are all wired in parrallel and one bad injector would affect all of them.

Another would be the charging and grounding systems. If the alternator, regulator cause spikes in voltage, and or the grounding of the engine and alternator are poor. The DME and harness are independant of the chassis wiring, aside from the voltage from the charging system and grounding to the engine. You should make sure that the connection from engine to the rear console has been properly wired now that the alternator uses an internal regulator and not the original external one. Ground strap from the alternator to the engine, along with the ground strap from the chassis to the transmission should be checked. All the DME grounds are on the intake runner and poor ground to the engine and chassis could hurt the DME, especialy if there are voltage spikes from the charging system.