I have a 91 940 GL that will sometimes not start the engine will crank but won't turn over. I have been able to start it with a jump but I've fond that it has to be a battery with a lot of power, small cars won't do it but a truck will. I've checked the alternator which seems to be fine. Any ideas???

Thanks

 

The battery is the first thing to check. Sounds like it's weak if a jump gets the car going... Seems like it discharges itself to various degrees depending on conditions... Also, check the alternator's charge rate while you are at it.

 

I checked the battery it's good at 12V I also checked the Alternator and it was up to 16.5V.

 

12v is on the low side, and 16.5v is too high a charging rate... i'd change that battery first.

 

I just went through an issue quite like this. Except I got waylaid thinking it was a fuel delivery issue. It was not. I have a '91 940 Turbo.

I had a battery that was on its last leg. It would not take a charge. So I went and got a new battery. I was shocked at the prices they're getting for batteries these days. So I got the cheapest battery I could find.

The car started once and wouldn't start again. Naturally, I thought to go through the rest of the electrical system. This is a good game plan: http://www.stepbystepvolvo.com/NoStart.html. Send the guy six bucks if it helps you, that's all he asks.

That battery turned out to be a bad battery. So, once I got a good one, I checked the alternator. It was not putting much back into the battery.

Alternators are expensive, too, so I went out to eBay and found this place: http://myworld.ebay.com/ebaymotors/bnrparts/. They're in California. They were very pleasant and a reconditioned alternator arrived in two days. I'm in Kentucky, so that kind of express shipping was notable.

I put the alternator in and the car started right up and runs well, so far as I can tell. I'm nervous and have only driven it about five miles out and back.

Before all this happened, I kept getting a warning light on the dash for the bulb integrity sensor. I chased bulbs all around the car but mostly on the driver's side, rear. Tonight I got another sensor warning and I checked the bulb. It was fine and the warning light quit glowing after I jiggled that bulb in the trunk area.

Good luck and keep us posted. I'd like to know what your situation ends up being about.