My 1994 850 stalls. it will run perfectly for a month and suddenly stalls and refuses to start. After three to four days it starts to work normal and suddenly starts all over again, cutting out in the midlle of driving. Any knowledge on why and does any one has a similar problem or dealt with one before.

 

Some known common causes:

- Fuel pump
- Fuel pump relay
- MAF (Mass Air Flow) sensor
- CPS (Camshaft Position Sensor) sensor
- ECT (Engine Coolant Temp) Sensor
- Neglected maintenance, etc...

Try retrieving the fault codes from the ECU. Since your 850 is of 1994, it may have OBD-II port in front of the shifter, right under the coin holder. Remove the coin holder to see if you can find electrical connection, and if you do, you could visit auto parts shops such as Autozone to have it diagnosed free (not sure if they still offer this service).

I will move this thread for better responses from experts.


JPN

 

Can you feel it start to stall before it does or does it stall out of no where?

 

my 94 volvo is having the exact same issues. we've tested the fuel pressure, that's fine. replaced the spark plugs and wires, still the same problem. already replaced the distributor and fuel pump a few months back but you may want to check out the distrubutor first, it's not too hard to see if it needs replacing. mine was burnt up pretty badly. hope this helps you out or gives you some options even though i'm still lost. this car can really cause you to pull out your hair sometimes : )

we've tested the coil and ignition module with mixed results and gotten codes for the intermittent signal from the cam and crank sensor. so that's where we are going next. we cleared the codes tonight and will post what we find when it dies next....

 

if it is non turbo remove the crinkley black intake tube that comes from the air box to the intake of the engine and fold it around and look for holes.

i have seen a constant issue with the tubes developing holes on the area of the throttle linkage area. i had/have the issue on both of my 94's. and i grabed a replacment tube from a part out for free, and it also had holes in the same spot.

worth checking to see if that is the issue. on my silver wagon it was stalling out constantly, but the holes were quite large.

 

Fyr-1


jpn

 

FYR-2


JPN

NOTE: These are from 94-96 turbo and yours may slightly vary in set-up.

 

the volvo is running fine now....we took out the ecus and blew everything out of there (they look like the old nintendo games so i figured it couldn't hurt to blow) and put them back. been driving it to work for 2 days now. don't know what was wrong but if it keeps working i don't care.

 

Something must not have been contacting correctly. Glad to see it working again.

Oh, and I like your Nintendo reference.

 

Thank you all for the suggestions, but the problem was the cam sensor. I put a new on in and the car works perfect now.

 

That's great! Mine died yesterday but started right back up and hasn't died since. I'm sure something will need to be replaced, I'll start with that. Thanks!

 

I just bought a 94 850 for $500 the owner does not want to mess with it. But after spending hours reading this forum, I now know with a high degree of certainty, it must be the fuel pump relay, the fuel pump, or the tape he used around the MAS. In short, it starts but won't stay running; stuff like that. Thanks .