Hi all,

The Volvo in question is a '91 244 5 speed with LH3.1. A week or so back, had a few difficult hot starts. Looked into Crank Position Sensor wiring, saw that the shielding was cracked open in a small spot, seemed to be original, so it was replaced.

A few days later, she cuts out for a split second while driving. Check engine light on for that split second. No codes stored--ie, get 1-1-1 flash with proper button pushing sequence per Bently. Check all obvious wiring connections--all seems good.

On the way home today, car bogs down badly, feels like it'll die and try to strand me, but recovers and makes it home of course. Check engine light was flashing rapidly for the 3 or 4 second episode. Try to restart once in the driveway, no hot start again.

Double check crank sensor connections--all is good for sure. Try to pull codes, get nothing--ie, no 1-1-1 flash. Instead, push the button, and the little red light doesn't come on. Try again, same thing. Turn ignition on and off a few times, push button again, light goes on when button is held down now, but does not flash any codes afterwards. Hmm...

Fuel pump relay fairly hot to the touch, but has a date of '99 on it. Haven't personally resoldered it, so swap it out with a known good one--still no start. No fuel pump whir with key in position 2. Run jumper wire from fuse 4 to 6, pump whirs, car starts and runs normally.

Try turning ignition switch on without jumper wire a bunch of times. Maybe 2 or 3 out of 10 or 12 get the whirring fuel pump--car will then start and run for a second or two, but then dies. No start without the whirring fuel pump of course. No change in symptoms with AMM unplugged.

So...sounds like a bad 572 ICU right? The lack of functionality on the diagnostic circuit seems very strange to me. Has anyone else ever seen this happen with a dying computer? Or does it suggest something more sinister and complicated?

I've only recently branched out into LH2.4-3.1, sadly due to rusty mid-80s cars. Of the LH's, I like the 2.2 best by far I'd say. My other 3.1 car is out of town for the weekend, so I don't have a duplicate ECU to swap in to be certain. I don't suppose anyone has a spare lying around in the Charlottesville, Virginia area? I haven't had these newfangled 90's cars long enough to accumulate a proper stash of spares...

Is there anything else I should check before I begin wiring in a K-Jet relay to bypass the fuel pump ground circuit on the 572--I forget who (so I'm sorry that I can't give credit where credit is due), but someone posted that very clever (and cheap!) fix a few weeks back, and I was, thankfully, just barely clever enough to save it. I must have had some sort of feeling that I'd be needing it one of these days...

Sorry for the longish post, I hope it was at least a good read, and thanks for any and all help!

Jon McKeon
Batesville, VA
'85 & '91 244s; '87, '88, & '92 245s.