BC

I will do the simple checks this morning in the light. Coil wire, ignitor, etc.

dr bob

If not already it will be soon. Brendan, it sounds a lot like the car is running on four cylinders. Soggy performance and the glowing cats are the telltales. Look at the ignition carefully, maybe with the inductive timing light to verify spark on both systems.

BC

I have a timing light but before I left for some errands, I took all wires off one by one to verify at least something changes with the engine note. All did. I reseated both coils. I'll drive to work now with a laser temp gun.

Just after a bit of driving cats were at 550 mid body.

hacker-pschorr

Pull the plug wires one by one while at idle.

I've diagnosed two 928's and my Scirocco by doing this. Each case it was a dead injector.

Disconnecting each one (then re-connecting it) causes the idle to stumble, when one has no change......it might narrow down the possibilities.

BC

Ugh. Barely getting up a hill. I have another ignition stage plate but I don't think its that.

It revs in neutral but not quickly. But once in gear, it barely can move without alot of throttle.

Spark plug wires all working. Rev change with all removals.

Cats are 800 degrees at the mid-to-rear section. I can remove the cats for a test pipe tomorrow or tonight.

transmission?

Any other ideas?

BC

BTW - its fine when its cold. Well, as fine as it ever was. As it gets warmer, it gets worse and worse.

Ideas:

Cats
Injectors? (not high on my list)
Temp 2 sensor (I can test with Voltmeter)
LH Brain (simply because of the way the injectors are clicking at idle)

Alan

Sounds like multiple cylinders with no ignition pumping unburned fuel into the cats - likely the cats are getting restricted by now. I'd be careful driving - you are at risk of a cat caused fire... Also at risk of shaft failure in the torque tube from uneven loading.

I'd be testing spark on all leads - not just cold - but hot too.

Alan

BC

I have driven a 928 that was running on 4. I know what it feels like, and I understand how it works when it is on the 4 out of 8.

I have, while its running in its non-reving state, remove the leads and it changed revs on all 8.

I will continue to investigate this but I am concerned its the wrong path.

outbackgeorgia

Sounds like an ignition coil. Classic symptoms of a break in the winding, wires touch when cold so work fine. Broken wire separates when hot causing misfires.
Seen this several times.
Dave

BC

Its not "cutting out" like its missing. Its firing 8 cylinders, but as if you are tied to a boat.

BC

I'll just have to swap out the cats as a first go.

I wish Greg was answering my texts or emails. I guess I pissed him off.

hacker-pschorr

It's the end of the week at an auto repair facility.
I don't dare call my local guy at this time unless it's an emergency.
The place is a madhouse with people wanting their cars for the weekend.

BC

I didn't call or email him today.

Alan

You are reading more than I said... I didn't say running on 4 cylinders I said cylinders without ignition pumping fuel into the cats. It may not be 4 cylinders and it may not always be happening or even always the same cylinders. The sluggishness may ultimately be as much about cat blockage as about #cylinders firing.

It does however seem extremely likely that raw gas is in fact getting to the cats - and there aren't so many ways to do that - losing 1 coil is one way - but not the only way.

Alan

69gaugeman

Yes, but pulling the plugs will give you an even better idea of what is going on. As well pulling the plugs is a forty minute ordeal, so it is not the worst job to do.