My 850 woes

peti · Post by **peti** » 10 Sep 2006, 12:23

The car: 1995 850 Turbo wagon, Auto transmission, over 200,000 miles.
The problem: Up until 6 weeks ago the car ran great.
Then while driving, the rpm's started to drop and eventually the car would stall, it felt like I was running out of gas. But it would re-start normally every time and then the cycle would repeat itself, each time restarting normally, only to stall again in 30 seconds or sometimes it will run normally for a few minutes or even longer.
The important thing to remember is that the stalling in completely random.
Things the Volvo shop,(not the dealer) has done:
Ran obc ll scan, no codes.
Checked fuel pump, ok, the pump is only 2 years old.
Replaced plugs, fixed vacuum leak.
Replaced worn turbo hoses.
Each time they did something they were convinced that the problem was fixed, but it was not.
Things I have done:
Through a previous post several people recommended that I replace the fuel pump relay. I had access to a S70, 1998, so I swapped the fuel pump relay from that car, and like a miracle the car ran fine, I drove it for about half an hour with no problem.
I was convinced the car was fixed. But next day the stalling started up again.
Cleaned the MAF sensor.
Removed and cleaned the idle air control valve.
Bought new fuel pump relay.
I am at this point at a total as to what to do, I really don't want to sink more money into this car, but I have the feeling that the fix to this problem is something very simple and obvious.
Any thoughts?

CarVolvo · Post by **CarVolvo** » 10 Sep 2006, 13:58

did you replace the fuel filter? Did the fuel pump relay not help the situation?

peti · Post by **peti** » 10 Sep 2006, 15:04

The fuel filter was replaced a couple of months ago, and no, the relay made no difference. Thanks.

CarVolvo · Post by **CarVolvo** » 10 Sep 2006, 16:42

i dont mean to harp on the same note...but... why did you change the fuel filter? you said you did about 8 weeks ago and you had a problem with the car 6 weeks ago?

I also wonder if you can report what the part number was on the fuel pump relay? I have heard you should only replace them with the same part code. Did you keep the newer relay on or put the original back and whats the difference in changing this problem?

Guess the only last thing to do is pressure test the system and have the injectors tested.... if its not the fuel, must be electrical.

Post by **robert213** » 10 Sep 2006, 17:06

Possible problem with fuel pressure regulator. You can check fuel pressure at the shrader-type valve on the fuel rail.

Hmmm, the car was running fine until you had the fuel filter replaced. I wonder if the wrong fuel filter and/or fuel filter was installed incorrectly.

Checking fuel pressure will reveal if there is a blockage in the fuel lines somewhere.

peti · Post by **peti** » 11 Sep 2006, 06:49

The new relay is the usual #103, part number 89 8797 000, red and this one was made in Hungary. It made no difference at all.