1993 Volvo 940 ~200k miles - just did a headgasket due to water leak (not in oil). Everything went great - if you call replacing headgasket in 10 degrees in the driveway great... Idled great for long time while I checked things out. Test drive through town and on freeway great. Got back to the driveway and it idled for a while. When I went to throttle it it studdered. (temp fine - not overheated) Next time studdered more, next time stalled. Started up again but stalled again on throttle. Each time getting worse and sometimes firing the engine backwords towards the end.

Note: forgot to hook up gound wires from back of valve cover to box on firewall for test drive. Fixed it immediately when I returned.

Put a timing light on it to check timing since I scribed the timing location when I removed the distributor. Timing advanced as I reduced RPMS and then light went dead and engine stalled. Definitely feels and appears to be electrical. Timing may be off, <12 - appeared to be at 0 at idle but never could get it to stable idle to be sure.

What ever is wrong went progressively worse till it only runs on a couple of cylinders. Definite gas smell out tailpipe.

Finally, when I double checked the timing belt, it appears to have worked itself about 1/4" toward the front of the car off the top pulley. COuld that be from firing backwards? Tenson is good...

Thanks - need to get this running or my wife's world comes to an end - 3 kids...

Mark

 

Yeah I would definitely check the mechanical timing on the car. Sounds like it jumped.

 

On my 1987 740, when I replaced the distributor, I had inserted it incorrectly. I knew something was wrong when I had too big of a gap between the distributor baseplate and the back of the valve cover. I went online and learned that the distributor key is offset. So, I pulled the baseplate off and rotated the key 180 degrees and reinserted. No gap. You may have inserted the distributor baseplate incorrectly. If so, I'm wondering how the car ran so nicely in the beginning. It's something to check out. (See www.stepbystepvolvo.com, "Replacing/Repairing the In-Line Distributor.")

 

Turns out Timing was fine although the belt is running even with the forward edge of the cam gear but its fine. Turns out that the problem is an intermittent electrical (I think) issue.

I checked the cam timing then put new plugs in it just out of superstition. It started up and ran fine - just like last time. Took it on a loop through the neighborhood and on the freeway. After about 15 minutes of running GREAT it died - just died. About the same amount of driving time before it died last night. Tried to start but would not - sort of like it was massively flooded. After 5 minutes It fired right up and got me home running fine ~1/4 mile. A few minutes idling in the driveway and it started with the dieing when I throttle it again. Back to trying to start but won't. Coil is not hot to the touch. Ignition timing was right on - checked it before I left when it was running good. 150 to 155 lbs compression. Any ideas?

I was very careful to insert the distributor correctly - did it on the workbench and noticed the offset - but thanks... I did however notice a piece of fiber washer under the stamped "washer" under the rotor that came out. It looked like the last piece of the washer left - maybe 0.030" thick??? Hardly seems like it would be the problem - why 15 minutes each time???

 

After reading the thread I would suspect maybe a sensor not connected like coolant temp sensor or O2 sensor not connected. I would double check all the connections that were removed during the head gasket replacement including ground wires. It's definitely related to the engine reaching operating temp. there is one possibility that is ugly to think about but it could be possible when the thermostat opens coolant may be leaking somewhere and shorting something out (wiring connector ECT...)

One other thing that might be a possibility is the ICM heating up and cutting out the timing light going out when it happened leads to ignition issue of some kind. I would swap it with one from a salvage yard just to eliminate it as a posibility.

 

I checked the sensor connections. They are ok. The car actually comes up to temp about 5 minutes before it stalls. Still could be something related to heat. No leaks anywhere - watching like a hawk!

What is the ICM? Got a friend with a Volvo 7/9xx junk yard 45minutes away. I can get most anything.

Boy does it run good when it runs good...

 

It's the Ignition control module, there are two types for your year make and model the regina type and the Bosch with/without bracket. Here is a page that shows what they look like. Sometimes they can heat up and just start cutting out then when they cool off they start working again.

http://shop.advanceautoparts.com/web...lacement+Parts

Most auto part stores can test them as well but the bad thing is they might test ok until heated up. thats why i suggest salvage yard good price and most likely you'll get a good one.

 

I would also suspect crank angle sensor. It lives underneath the distributor, wires could've been damaged during the work. They're also known to die by themselves too.

Regards, Andrew.

 

I believe this car has it down on the crank as opposed to teh distributor. THere are no wires going to the distributor