Hey everyone, I have a 1990 240dl that has been stalling intermittently for months. I've made multiple posts about it months apart; sometimes the car will go weeks without any issues and then randomly act up again. It's driving me nuts.

I will be driving (could be idling at a stop light could be going 45) and without any warning, the engine will die and all the dash lights will come on. I have to coast to somewhere I can pull over and then try to restart the car. Sometimes it will fire up right and away and other times it will crank and not start until I let it sit for a couple of minutes then try again. The car might die again on the drive back home, but once it sits overnight it won't act up for at least a couple of days. Other times the car will be so perfect that I think it's invincible.

What I've Done:
-New MAFS
-New Fuel Pump Relay
-All fresh fuses and cleaned the terminals
-New cap rotor and wires
-Friend bought me a Crank Position Sensor almost a year ago but I don't know where he got it, so I have a new one on the way from IPD - From what I read these symptoms sound like a CPS.
-All engine bay grounds cleaned and tightened
-IACV cleaned and tested
-25 fuse on the driver's side fender checked and seated tightly
-Checked fuel pumps by jumping fuses 4 and 6

I read somewhere else on here that when everything turns off instantly "like a light switch," it means it is an electrical problem. It also seems like it would not start up so quickly if it was a fuel issue. Some other things to think about: Sometimes when I start the car it will have a really rough idle, and I can massively change this idle by flicking on and off the brights or doing other things that mess with the alternator. Flicking on the brights causes a significant change in rpms and the smoothness of the idle. Could the alternator be the issue? Additionally, the car was recently broken into and the speakers and stereo head were chopped out and taken. Now there are a lot of bare wire ends where the stereo should be. Could something here be causing this issue? (I doubt It because it has been happening since before the break-in). Also, the little black box with some wires connected to it on the inside fender (near where the white 25 fuse is) -mine has no cover. I had some radiator problems during the summer and there were a couple of coolant explosions. Could the coolant have permeated those connections?

I'm actually going insane because of this issue and literally anything that could possibly be causing the issue I want to check out. Thank you for any advice you can offer.

 

My best guess is the CPS. Don't know what brand your friend gave you but symptoms lean that way. Also, you should address any bare wires from the stereo by capping them off with heat shrink or electrical tape to ensure they don't cause problems. There is a "hot" wire in there somewhere for power to the radio. It shouldn't cause any stalling but could blow a fuse if it touches a ground.

 

Even determining if its a fuel or ignition problem would be a big help. Prepare to do a few simple tests when the problem is occurring. Carry a meter. Hook up some wires to test points ahead of time to make tests on the side of the road easier. Even run the wires into the cabin. I'm not familiar enough with the later models to recommend what to measure or check but I'm sure there are many here who can.

 

Thank you both for the responses! I replaced the CPS with the new one from IPD yesterday, and I haven't driven it extensively but so far no issues. I'm probably going to try and cap the stereo wires today.

How would I go about testing whether it was an ignition problem or a fuel problem?

 

I'm a 740 / 940 guy, but I suggest you swap the fuel pump relay with a known good or replacement one.
Not sure about the stall issue, but could certainly be related the restart issue.
I've kept a generic one in the glove box and needed it once.

 

The fuel pump relay is a brand new Stribel one from FCP Euro. I have a backup one from the junkyard in the glovebox and a cheap Chinese one in the trunk just in case.

 

Connect a 12v test light to the flashing side of the coil, mount that light inside the car. When the car dies watch as the engine is coming to a stop - Is the light still flashing? If so the fuel system is causing the stall.

Same thing with the fuel system, connect a fuel pressure gauge and tape it to the windshield. When the engine stops running - does the fuel pressure drop and then the engine stalls?

You have OBD1 - what codes are stored in the fuel and ignition systems? If you are not aware
https://www.volvoclub.org.uk/faq/EngineOBDCodes.html

 

My 91 740 has a 4 wire connector from the only intank fuel pump ( regina system) located in the trunk drivers side close to where the aluminum fuel fill hose is. Two wires are for the sending unit and the other two are for the fuel pump ( pink +ve , black -ve) I had a similar issue similar to what you are experiencing except the car would not die while driving. Some days it would start other times it would not. Hot or cold ambient temperature , it did not matter. The culprit was a corroded termnal connection of the pink +ve wire. I guess after so many years the heat and high resistance at the connectiion in the connector enabled some corrosion to form . I bypassed the connection at the connector and hard wired the pink positive wires. Check all your fuel pump connectors for corrosion.

 

Thanks, everyone for the input! It has been a couple of weeks since I replaced the crank position sensor and so far I have had no issues! I think it is safe to say that that was the fix.

 

Glad you got it fixed!