I have a 1993 940 non-turbo, AT, 210k miles. I recently acquired this car from a tow auction, and the thing runs and drives pretty well. I had to replace the overdrive relay, and now after driving it for about two weeks, it has gone from running consistently to/from where I need to go, to cutting out after driving it for about 5 minutes.

I have browsed all the FAQ's and all the possible solutions make sense, however I would like to eliminate some of them to try. It fires up with no problem whatsoever. It is idling outside pretty smoothly right now. I have test driven it around where I work, but I haven't been able to recreate the problem in a test environment. I really don't want to have to take it down the road and have it stall again in traffic. When it stalls out, the dash lights up (don't know about the tach, haven't checked it, but I believe it hits 0, will check next time) and the car stops running. Not sure which ignition system is in the car (the FAQ's said they can vary, and I don't remember if any of them said how to check). Sometimes I am able to restart it after a few seconds, sometimes 30 seconds, but it does restart pretty quickly. The car is warm every time this happens. The stall happens on the freeway at consistent RPMs, and going through town accelerating/decelerating.

Any assistance with this problem is greatly appreciated, and I will answer any other questions as quickly as possible.

Edit: I remember reading somewhere that the RPM sensor should be under the distributor near the bell housing. My distributor is in the block. Don't know if this makes a difference or not.

 

In my 1990 240DL wagon I recently experienced stalling just as you described. Most of the time it would also trip out the error code 1-4-4 (Load signal from MFI system absent). With the invaluable help of forum user swiftjustice44, I was pointed in the direction of the fuel pump relay. It's been a week since replacing that relay and I have not experienced any more stalling.

 

Two likely culprits for this sort of behavior are the fuel pump relay as already mentioned. The second is the Crank Position Sensor. I am not familiar with the 940 but I beleive it has the CPS. It would be located on top of the bell housing where the engine & transmission meet. Check the wires on it. If they are cracked or frayed, it's time for a replacement.

 

I pulled out the Fuel Pump Relay, took off the cover, and everything looked good in there. However on the case, it was time stamped June 1992, so I assume it would be a good idea to just change it for kicks.

The CPS sensor was my next guess, and I was planning on replacing it ASAP. I test drove the car around where I work, and it didn't reproduce the effect, tried everything I could think of to make it go bad and no luck. I really hate throwing parts at a car, but those two seem like the most logical culprits. Thanks for the replies.

 

If you don't want to spend any money at all and you have a soldering iron, just take the plastic cover off of the Fuel Pump relay. There is a circuit board in there that the solder joints crack over time and make intermittent connections. Just re-solder them and try it out. If the problem goes away, then you know can always replace with a new one to give you piece of mind.

The solder joints that typically go bad are the ones that attach the coil. I think the vibration over time combined with the mass of the coil tend to crack these joints.

Good luck