View Full Version : Help, Mechanical Problem!!!

Wednesday 27th April 2005, 13:35
i know this is not exactly on topic given im driving a 940 but you guys have always been really helpfull and it semms to be a more general thing since i know a few people have had this complaint in several different cars - including my dads 2 year old land rover!?!

as we speak im havin a new oil pump fitted since it couldnt generate enough pressure on low revs
i dont think this is connected but intermitently when im driving along in different circumstances ie sometimes motorway sometimes turning a corner etc, everything dies,
i have my foot on the accelertor and nothing happens all the power goes i change gear release accelertor press brakes etc and nothing just keep slowing down then as suddenly as it started it stops and the car picks up again, and away we go. as if nothing had ever happened
occasionaly the car slows right down into a stall and its hard to get it going again
the simplest way to describe this is as if someone stands on a garden hose and then takes their foot off it again if u see what i mean. thats how it feels.
ive had my mechanic have a look and he cant see anything out of place, and as its so intermitent he cant test,
its happened to me twice on the motorway and its gonna cause an accident so i need to troubleshoot this guys help!??!
i thought flooding or starvation of something,
or possible a vacumm leak?? :slap:
car is 1991 940 estate B200F non turbo engine

Wednesday 27th April 2005, 14:14
I have heard of this type of problem on other cars but it happened to me with a 960 turbo that I used to own.

The symptoms were like yours inasmuch as it would just die and pick up again when it wanted or just come to a stop. It would restart until the day came when it wouldn't and the AA were called.

No sparks led to the testing of 2 or three signalling components and the fault was traced to the crankshaft motion sensor circuit board. I was surprised at how many signals have to be present before a spark is produced and how many components are involved. I guess its all for anti-flooding, cat protection and pollution stuff.

Next time it stops and is reluctant to start whip off a plug lead and check for a spark. If it is missing then the major suspect is that board (they crack with age). I wouldn't bother trying to trouble-shoot the problem as the AA guy did on mine. He damaged a sensor lead with a probe and cost me another fifty notes just because he was a bit too keen to get the car going. The sensor lead not to damage looks like a thin black floppy HT lead. It has a core that carries a sensor signal and if the screening is damaged its toast.


Wednesday 27th April 2005, 18:52
as mentioned above cheack the senser at the rear under the distributer by the bellhousing ....... but on anouther note i had the same thing on my old 940 witch was the posotive batt terminal make sure both nuts are done up tight on the terminal clamp.. one nut clamps the aux wires if that is loose on it it will go then stop then go again mostly when going around corners took me ages to find it and after i fixed it i asked my mate at volvo and he has seen it a lot when people change the batts and do not cheak both nuts.. hope that helps

also changed a clutch on a 940 in 35 mins