PontiacBonnevilleClub.com

Moin, Moin,

Unfortunately, I'm having problems with my Bonnie, again. I have no experience with the 3.8L engine, and in Germany, there's no repair shop that's familiar with them.

When the engine is cold, it runs well, with all cylinders.
When the engine warms up, it sputters, and it is running on 5 and 4 cylinders
At high revs, the engine running again on all 6 (over 3000rpm).

If I unplug the injector connector when it's running rough,
I can locate the cylinders that aren't running.
I've swapped the injectors, and they're not the problem.

I suspect broken wires. (I've already located and repaired some in the past.)
I'd really like to replace the wiring harness on the engine, as it's been tampered with.
Unfortunately, it's not available as a spare part. At least not from the usual sources.

Does anyone have any other ideas? Or a source for a wiring harness?

Spark plugs are new.
Ignition wires are new.
I have sparks in every cylinder.
compression is finde too

Regards Mike

I would swap the ignition coils to see if the problem cylinders you located travel with the coils.

Coils are one Block... And the cable comming from the ignitions ecu are short...
I will see how I can do.
You think is tis not in time or to low?

I didn't remember the coils are one block on the magnavox system. It might be worth it to source a 92-95 L27 ICM, coils and bracket. https://www.pontiacbonnevilleclub.com/f ... c1684.html

I don't think the engine is out of time. The hall sensors are either going to work or not. There's no adjustment.

Moin, Moin,
I'm very grateful for the tip about the ignition. Since I had a clear spark from each plug, I didn't anticipate that it might be too weak. (The wires and spark plugs are quite new.) That was rarely a problem with my German cars.

I'm very lucky (or unlucky) to own a 94' Prontiac Trans Sport 3.8 that uses the L27 ICM ignition system. I was able to exchange it.

Now the car is running again... I still can't believe it. Now I need a new ignition system for my TS... It's almost impossible to find used in Germany, and it's ridiculously expensive as a new part...

That's awesome you had that available to at least troubleshoot. You might have some luck on US ebay for seller willing to ship the ICM/coils internationally.
I was able to get someone on ebay Australia to ship to the US before.