1993 Pontiac Trans Sport 3.8
 

Now I have the first time a problem with my TS where I can not get any further.


The problem is, at cold start he always jumps and top, but as soon as I turn off the engine and he is 5min, he does not start, until he has stood about half an hour to three quarters of an hour.
Spark is there, fuel pump starts at ignition and also builds pressure, but he does not inject, we tested it with brake cleaner because he runs short and goes out again, we thought that the signal from the ECM is missing for the injectors, have tried it with another ECM, same result.
All sensors new !!!
So the engine runs absolutely top and clean.

Error code 26: Engine control module (ECM), quad driver / output driver -circuit malfunction

ECM, PCM, crankshaft sensor, camshaft sensor new.

If you have good spark on all cylinders, I am thinking fuel.....

I assume this is throttle body injection? When it won't start, I assume nothing is coming out of the injectors....I would guess if you sprayed carb cleaner into the throttle body while cranking, it will start?

If this is the case, you either have insufficient fuel pressure(I think TBI only needs 10-13 psi) due to a bad pump/connection, the injector(s) are bad, there is no injector pulse(check harness with a noid light), check for power at the injector harness(verifies fuse is ok), you have a bad wire harness(have seen these get damaged), or a bad ECM.....

I mistakenly thought this was a TBI system, it's sequential.....

If you can start the vehicle by spraying carb cleaner into the intake(when it won't start), my guess would be the ICM, if you replaced the ECM with a good one.........It seems like you are not getting a reference signal from the ICM to trigger the injectors.......before replacing the ICM, make sure the connectors in the harness to the ICM are tight, and there are no breaks in the harness....

I wonder if we are dealing with the first generation Multitec injector shorting issue as soon as they heat up?

This shouldn't be a problem, because this is sequential, not multi port......

With multiport, a shorted injector would take out all three injectors in parallel, by the quad driver that controls them.....

On this engine, it would only take out one........

Also, when injectors go bad they go bad......it sounds like the ICM gets "heated up" and then doesn't perform until cooled down...

Good to know! I knew the MPI with the 3300 would exhibit this, and the '93 3800 was SFI, but his Quad Driver error had me wondering.

Have you verified with a test light that there is no injector pulse when this is happening?

If this drags on I may have to dig out my FSM's for insight on how the PCM works.

Also, did you check fuel pressure with a gage when it won't start?