Hello from Belgium everyone,
I drive a Volvo 940 - B200F from '92 and I'm experiencing intermittent stalling issues, that occur after the car sits for 1-2 days without being driven. Usually on Monday when I'm driving to work when stopping at an intersection it stalls. It fires up after 5-10 seconds \, although I feel like she's purring a bit worse. I tend to keep her a bit higher in RPM's at traffic stops (after stalling) to prevent her from stalling again. When driving back from work she runs great again.
Following parts were already replaced:
- Spark plugs
- Crank sensor
- Fuel pump relay
- MAF (I used a spare one I had laying around)

My local all round car mechanic doesn't know what the problem is and I don't want to keep throwing parts at it hoping the issue gets fixed.
Thank you al for your suggestions!

 

In order of probability, my best guess would be weak or failing fuel pump, partially clogged fuel filter, weak or failing coil.

 

Hi Psaboic,
Thanks for taking the time to reply. This morning the same thing happened again, but now it wouldn't start right away and took multiple tries to finally stay running. I managed to drive away but it wouldn't idle very well. After about 5 minutes of driving the car ran fine again (sidenote: fuel level is less than a quarter full).
- Weak or failing fuel pump can be diagnosed by measuring the fuel pressure? I have a kit laying around so I would be able to check this. Any other things I can check of the fuel pump is failing or not?
- I can swap out the fuel filter with a new one; I think it's already a couple of years ago since this happened.
- Failing coil; multimeter check?

 

Yep, check the fuel pressure and also the coil output like you suggested. Another idea came to mind. Check or replace the coolant temperature sensor. There are two sensors on the engine....one runs the gauge in the dash, and the other sends a signal to the computer to adjust the fuel mixture based on engine temperature. If the sensor feeding the signal to the computer has failed it may be telling the computer the engine is already hot, thus leaning out the mixture and making a cold start very difficult, and once running it will run rough until the engine actually DOES warm up and can properly use the leaner fuel air mixture.....

 

Thanks, haven’t done any of the above just yet. But I’m here with some more details:
When returning from a trip to Germany (300 mile trip) over the weekend, we did a small pitstop to stretch the legs bur after 30 mins the car wouldn’t start anymore. I believe the culprit here is the starter (banged it with a hammer and she started fine), so a new starter is on my shopping list.
Today however, I stalled lots of times doing my regular commute. Starting became very hard, had to hit the starter with a hammer a couple of times, bogging down immediately, not being able to keep running. In the end I had a spare set of spark plugs laying around and I installed those. The car started immediately afterwards, and I managed to continue my way home. 5km from home the car started behaving again; rough idling, surging, but I managed to keep it running until I was home.
I always have a spare set of spark plugs, changing them once every 3 months. In this 3 month period the car eventually starts acting up (rough idling, occasional stalling) but when changing the plugs this immediately is solved and I get to drive it around happy again. Right now this “trick” doesn’t seem to work since it’s running rough again after 15 minutes.
My apologies for the incoherent info, but I’m just throwing it all on the table here.

thanks!

 

I've had intermittent starting and rough running problems in the past on my '93 turbo and it turned out to be the crank position sensor. I thought at first it was related to engine heat. The cable looked fine on the outside but it was corroded on the inside. When the engine bay was warm the cable expanded and it lost it's connection. When it cooled down the cable shrunk and it worked again. Cheap and permanent fix.

 

Thanks for the tip regarding the CPS. I've preventively replaced this one 1 year ago, so I would assume this one hasn't gone bad yet.
To add another thing to the symptoms; car is running really rich with a very distinct petrol fuel smell inside of the car.

 

If it;s running rich then it could be the FPR (fuel pressure regulator)? Easy to check -
https://www.brickboard.com/FAQ/700-9...sure_Regulator