850 shuts off while driving - sometimes

javaqen · Post by **javaqen** » 06 Sep 2009, 16:33

Thanks Jagger - we had the battery checked and it "passed". This afternoon we removed the fuel rail, removed and cleaned the injectors, & replaced the o-rings. From trying to start it so many times the last few days we did run the battery down. So, this afternoon we jumped it and lo & behold - it started! It ran steady for a good 2-3 minutes. We revved it, got good rpms and were thinking we had finally fixed it. As we were standing & staring at the engine (read: patting ourselves on the back), it shut off. No stutter, no hesitation, just died. It hasn't started again since. However, NOW the CEL is on. Lol! I think it's possessed and will begin looking for a Volvo exorcist.

westfp928 · Post by **westfp928** » 06 Sep 2009, 23:23

One of your codes "A-2 131, rpm signal" tells me that you have an intermittant CPS (Crank Position Sensor), which can do what you are experiencing. I would check the connectors to it, and if ok and still has same problem, replace the sensor.

Post by **Ozark Lee** » 07 Sep 2009, 04:35

One other thing to check is the proximity of leads the RPM sensor (Crankshaft Position Sensor) to the coil wire. In its natural state the sensor leads want to loop up next to the coil wire and the coil wire can interfere with the sensor signal. Volvo had a TSB on that problem that calls for using a zip tie to fold the CPS sensor leads down away from the coil wire.

The RPM/CPS sensor is located more or less in the center of the top of the bell housing.

...Lee

javaqen · Post by **javaqen** » 10 Sep 2009, 16:55

Just a quick update - of sorts. We replaced the camshaft position sensor today because the parts store ordered the wrong thing. Still no start. Crankshaft position sensor should be in tomorrow. By the way, upon close inspection, my husband noticed that the plastic in the center of rotor button has a crack in it. Could that be causing this problem? My assumption has been (after we hit the $300 spending mark) that it will be a $10 fix when we finally find it. Will keep you posted - thanks again for ALL your help and advice on this

Post by **Ozark Lee** » 10 Sep 2009, 18:38

By the way, upon close inspection, my husband noticed that the plastic in the center of rotor button has a crack in it. Could that be causing this problem?

Yes it could. It may not be the ultimate problem but it is likely a contributing factor.

...Lee

javaqen · Post by **javaqen** » 13 Sep 2009, 09:04

This is turning into the little fix that wouldn't. Lol! So, the screw that holds in the crankshaft sensor is stripped and after TOO many attempts, seems impossible to remove. Does anyone have any suggestions for getting it off? Because of its location, access is limited. We have tried an extractor, and various sockets (all of which took a scenic tour of the backyard, btw) but nothing will grip. It was suggested to remove the heater hose and the 2 bolts that are on the "back" of where this part goes in and the entire plate should come out - allowing us to put it on a vice and work with it. Is the only job of this screw to simply hold in this sensor? If so, is there a way around it?

Post by **Ozark Lee** » 13 Sep 2009, 09:50

If you have a dremel tool try to cut a slot in the head and then use a flat blade screwdriver. PB Blaster is your friend here.

You can also "wake the bolt up" by giving it a rap with a hammer.

...Lee

javaqen · Post by **javaqen** » 18 Sep 2009, 09:31

I'm happy to report that the screw has been removed, the crankshaft sensor has been replaced (along with a new rotor button) and the car started!! But ... now it is idling really rough and there is a strong exhaust odor for the first few minutes it runs. I've run it for a few days and the gas mileage is now atrocious. Hubby thinks its running rich. Have we fixed one problem only to have created another? Oh, and after getting it running on Monday evening, driving it on Tuesday & Wednesday, on Wednesday evening when we tried to start it to add coolant we had the same no start situation. I tried to start it on Thursday morning and it started right up. I chose not to drive it for fear of getting stuck somewhere and it sat all day. Today (Friday) I just went out to try it and it started with no problem - just the rough idle. I'm still pulling a 314 code on A6 (even though we replaced it) but it appears everything else has cleared and is okay.

Additional Update: Started fine this afternoon (Saturday) and decided to drive it. Made it from our house to interstate (less than a mile) then onto interstate for approx 5 miles at 70mph when check engine light came on and engine shut off. Wouldn't start for a few minutes, then hubby hit throttle body with his hand and it started right up and brought us back home. Still sitting but starting okay with each attempt.

850 shuts off while driving - sometimes

Re: 850 shuts off while driving - sometimes