Intermittent stall while driving my 940 turbo wagon. Wait 5 minutes and it will restart, run fine until ?? the next stall. Can't find anything on "MFI" in my books. Can anybody help? BTW, this is a "re post " of an earlier call for help.
Thanks
Joe

 

Is the speed sensor and power stage good?

 

Speed sensor, ie crank position sensor? Haven't checked it but if it's something to rule out I will. Power stage is a term I'm not familiar with. I'll look through my chilton to see if I can find a description. I had similar stall problems with chrystler and a geo storm and they were both "faulty ignition modules located within the distributor and heat related, ie let the car cool for 5 minutes and it will restart and drive like nothing was wrong until it heats up and craps out again. Is the power stage a similar device "volvo style"?
Thanks for the comeback.
Joe

 

The speed sensor is in the back of the block if you have one. But if you don't you will have a pick up in the Dist. That goes bad the same way.
If you have a speed sensor and the outer sheilding is bad replace it.


The power stage is a module about 3 inches long and about 1 inch tall. It is mounted on a small aluminum bracket mounted inside the drivers side fender.

 

Thanks again, I'll be looking for both, hopefully this evening after all else is done. Sad when my auto repairs doesn't top the "honey-do" list!
Joe

 

Located both items. Power stage looks like one of those electronic modules that has no testing options besides checking power to it. I just pulled the connector and checked for corrosion, none found, justa a bit of grease to keep things nice and connected. The sensor on the flywheel connector looked the same. The cable for the sensor looked pretty new and clean so that part may not be the cars original, but it looked to be in perfect physical condition. It had a 3 pin connector, but my book only listed a 2 pin for the car. I tested the connector and got 180 ohms across the center pinan one of the side pins, notihgn worth mentioning across any other combination. Also flipped the key on ang got 3.5vdc across the center pin and one side pin on the other half of the connector. Does this mean anything ? I'm expecting another manual in the mail from e-bay soon hopefully with a bit more details on troublshooting and various test readings. Get back to me if this means something or if there are additional tests to be performed.
Thanks
Joe

 

I don't have the specs here so im not sure.

For giggles haev you checked the fuel pump relay and injector relay under the hood?

 

Didn't check either one honestly. The car has died while at idle and also while driving. I pulled the connector from the crank sensor just to see if it would die and be hard re-starting as it did to me this week. It acted exactly the same except Icould not get it to set the code? Electronics can be strange sometimes. I think I'm going to bac off for a few days until I get that other book. I'll give those fuel items a shot just in case,ya never know!
Joe

 

It's been a while, but I broke down and took the car to the local Volvo independant repair shop, excellent and honest, but I'm a stubborn DIYer soI was hesitantto go to him. He checked it all, and replaced the fuel pump relay and fuel management system relay, an inexpensive option to the $1200 fuel managment computer. All has been well for the last few months. He said it was the best way to go since he almost never replaced that computer on those cars.

 

It's odd that you updated on this thread yesterday because I too am trying to figure out a 144 that I got just the other day. My car doesn't stall out or anything, but the code keeps coming back time and time again. I'll have to replace those relays and see if that helps. Thanks for reporting back as to what fixed your car, it makes all the difference in the world for another person who's chasing the same problems as you had.

Thanks again,

Dale