Hi,

My '94 945T sat for eight weeks while I was away at Summer School. I had to jump it when I got back but it ran Ok after that. After having to jump it a couple of times last week and figuring out the battery was seven years old I replaced the battery.

Now, intermittently, it loses power and quits running but will usually re-start ok after a couple of minutes... It seems to do it more when warm and it also seems to hesitate a bit under load on the highway just now. Any ideas? It's a bit un-nerving when it quits in traffic...

Thanks

I own a 1993 Volvo 940 Wagon with Regina Fuel/Ignition System. Vehicle has 220K miles. My systems were after and only after driving 20-30 minutes there was a engine power loss with tach gauge fluctuating erractically, dropping from 2000 rpm to 1000 rpm around 40-45 mph. At highway speeds (55+) at every bad road expansion joint the tach would rapidly dip 200-300 rpm and then stablilize. Power loss also would occur at slower speeds and sometimes after coming out of a turn. The feeling of this stumbling and dread of stalling was all the result of a failing "REFERENCE SENSOR" (aka: crankshaft position sensor). I hope this tread helps others.

I've had this happen to me several times and always found it to be the fuel injection relay. This can be located in the fusebox area. I used to get them from the junkyard, but now they are only $16 @ FCP!!

Hope this fixes your stalling issue, good luck!

Thanks for your reply. I remembered the spare FI relay from my old 740 and installed it. So far so good!

3 areas to consider, especially since the problem occurs when engine is warm:
1) as already mentioned the ignition power module, especially if the car's mileage is around 150-180K
2) fuel pump relay
3( radio suppression relay (also known as fuel injector relay)
one more item - the engine temp sensor
Augie

Old air filter will make engine hesitate when hot, hard to start, loose power. An overheated power stage going bad would take more than a few minutes to cool and be able to restart the engine, I think...not sure.
A crank sensor going bad does fanny things when hot.
The the hard one is fuel pressure. This would be tough to check without a gauge. It could be the problem.

Hi,

The air filter is new... I did wonder about the crank sensor and maybe the fuel filter?

Guessing blindly here... have you thought about the power stage? I don't know if it's an issue on the 9xx series, but it is on hte 7xx.
Judging from the heat issues and realtionship to being excesively hot, and it just restarting once it rests/cools off, that might be just the thing.

I remember reading about heatsink grease between the power stage and the sheet metal of the body to dissipate heat. Apparently it dries up and stops conducting heat (saw this when working with computers). I would go with some arctic silver 5 thermal grease for like 5$ and apply it to the contact surfaces. It won't dry out for a couple years, unlike plain jane thermal grease.

Also, it may have nothing to do with that, so do you have OBD2 or OBD1? maybe a buddy can hook you up with a code reader.

-Will
--
1990 740 Turbo, on its way to stock specs, maybe beyond

Thanks, I'll check into that and look for codes...it's OBD1 just like a 740.