Posting here because I took it to a mechanic and they couldn't replicate the problem so they didn't have anything to fix. I'm willing to proactively replace parts, but need some ideas to narrow it down.

The engine wouldn't start one day. It tried to turn overbut just never fired. Tried it a couple dozen times the first day and eventually gave up. Next day I tried again and on the first try it almost fired. After that it was like before where it just kept trying to turn over. Next day, was the same thing.....almost fires then just unsuccessfully tries turning over every attempt after that. The third day I gunned the gas as it tried to fire and the engine started. The idling seemed kind of weak, but it ran all the way to the mechanic and fired up every time they tried it and every time I've tried it since.

It's a fantastic car, 200K miles, but the transmission was rebuilt before we bought it a couple years ago and it has run fantastically. Has been our temporaryfamily car, but now we're afraid to take it out anywhere for fear of being stranded. I'd love to fix this problem because, like I said, it otherwise literally drives like new.

 

Fuel injection relay, pretty sure... In the area above the ash tray, in the back behind the fuses, usually white, large, square...

 

I had the same problem with my '94 940. Non-starting intermittently. Mechanic couldn't find anything wrong. The next time the engine wouldn't start, I checked the engine's Data Link Connector. The LED flashed the code 2-1-4 which indicated the Crankshaft Position Sensor, a.k.a. RPM or impulse sensor, was bad. Replacing it solved the problem.

 

it could be that the fuel injectors not being fired - the speed sensor might be bad. try also checking the fuel pump relay and also look for some dirty connections -try to clean everything. I've experienced it before, after thorough inspections on my volvo 740 parts it turns out that the relay was bad and injectors also need a replacement.. anyways, good luck with yours and hope you'll fixed it soon.

 

Thanks guys. I appreciate the responses.

Went ahead and order both the sensor and the relay and will try swapping them myself. Will keep you posted.

 

ever try the ignition module? i believe also called power stage