1994 850 wagon.
From time to time the engine stalls when driving but usually recovers again, when it happens in idling, the engine stops completely. It scares me when it happenes on highway and I commute 90miles each day.
Any help is appreciated! Thank you!

Check this.

My '95 855T set a Check Engine Light and had become a bit soft in power delivery. Sometimes even giving the impression that the engine was off during deceleration or steady state cruising.

Had to be a vacuum leak with the 2-3-2 code. The car has 143,000 miles on it by the way.

I pulled the plastic throttle body cover off to inspect the rubber elbows on the vacuum tree which I have had to replace in the past. They looked fine. I started the car with the plastic cover still off of the throttle cable drum and it wouldn't idle. Died every time. Looking at the back side of the vacuum tree I saw a 1/4" hole worn through the plastic. Lots of unmetered air entering the manifold there causing the lean condition. The plastic throttle drum cover had worn the hole into the plastic vacuum tree. With the cover on and against the hole, it seals well enough to run but had gotten progressively worse.

Fortunately I had a new spare vacuum tree as I was going to replace it when I did all the vacuum elbows this weekend.

Put the new part on and it runs like new.

Erwin in Memphis... for now.

I had a similar problem with my 1993 850, where it would stall while driving/idling, and then be able to be restarted again in a few minutes. I replaced the fuel system relay, the fuel pump relay, and the ignition switch (it was dying anyway), and it seems to have fixed the problem. It hasn't stalled since. Something to look in to, and the parts are all available for a reasonable price at eeuroparts.com.

Kyle

Stalling on 850's usally because of a few things:

Mass Air Flow meter bad. Easy to replace two torx screws and a plug on the left side of the air box to throttle body hose.

Cam position sensor. Easy fix. two torx crews and a plug. to the left of the distributor cap. usually leaves an error code when going bad. buy a haynes manual for a listing of error codes.

voltage regulator....usually you will see "twinkling" warning lights for a bit before it dies. spensive.

Check all the hoses going from and to the air box and throttle body. make sure there are no cracks and the clamps are tight.

when the 850's stall, it's almost always because of:

1. Mass air flow meter on air box. (easy fix plug new on in on line off air box. held in place with 2 screws.)

2. Cam Position Sensor is going bad. This is easy to replace as well. Two torx screws on drivers side of engine to the right of distributor. Will usually leave an error code if going bad.

3. Voltage regulator going bad. Usually you will see lots of "twinkling" warning lights on dash. You wont go too far when it goes.

4. Check all the air intake fittings and tighteners from the air filter to the throttle body. Make sure they are all on tight and not cracked.

My guess is a bad MAF. I had similar experiences due to this failure.

Paul
--
1982 240 DL (265K) , 1996 850 GLT (125K)

Take a look at the DTCs for A-2 and A-3 and see if there are any, and then try to clear them out.
You said that you are using a lot of oil, so have you cleaned out your PCV and the small vacuum line attached to it?
There are too many possibilities at this point to solve your problem. It could be a dirty TB or MAF, a severe vacuum leak, a loose engine ground wire, etc. If there are no codes, it needs to be fuel related.

Klaus
--
Please answer your responses. We need to know if the advice is good or bad. The 164 has a new home, all I am left with are 2 turbos :)

I posted the inital question and just read A2 and A3 codes:
on A3
2-1-3 Throttle switch signal (wide-open)
2-1-4 Ignition rpm sensor signal erratic, absent or faulty
1-4-1
1-4-2 ECU faulty

on A2
1-1-1 No faults
Please, let me know if this can help troubleshooting. I am still clueless.
One more thing about the car it occasionaly gets both ABS and TRAC light while driving - next time I start the car they are reset (off), but eventualy turn on while driving.
Timing Belt was changed 15000 miles ago.
During the last tune-up (3k miles ago) Vacuum leak at the intake manifold was repaired.

Thank you for your help!
Victor

A3 code definitions:
2-1-3 = Left side rear wheel sensor, no signal on moving off
2-1-4 = Right side rear wheel sensor, no signal moving off
1-4-1 = Faulty pedal sensor, shorted to ground or supply
1-4-2 = Faulty stop lamp switch, open circuit or short circuit

The above is why your ABS light is on. The ABS system is checked at the start of each driving cycle when you get up to about 18mph. These codes cannot be cleared, except by the ABS module during its self check.


I forgot, have you replaced the fuel pump relay? If that fails, then your fuel pump also stops.

Klaus
--
Please answer your responses. We need to know if the advice is good or bad. The 164 has a new home, all I am left with are 2 turbos :)

You listed A-3 which is ABS codes. Sorry, my fault. Clear them and see what comes back.
A-6 is ignition problems, take a look there. Just make a tempory list of the codes, try deleting them, and post back with codes that come back again.

The reason for deleting: you don't know what year the DTC was set :)

I like to go through all the slots, every time I change the oil. Gives me something productive to do while waiting for the oil to drain.

Klaus
--
Please answer your responses. We need to know if the advice is good or bad. The 164 has a new home, all I am left with are 2 turbos :)

Code on A6:
2-1-4 reset to 1-1-1
Code on A1:
3-1-3 could not find description of the code
Code on A2:
is still 1-1-1

Also I tried reseting A3, but did not work (it worked on A6). Here is procedure I used:
Ignition OFF
Flylead into A3
Ignition ON
Press Button for 5 sec
LED ON (LED NEVER COMES ON)
Press Button for 5 sec
LED OFF
Ignition OFF

(Note: when car stalls all light on the dashboard blink for a couple of seconds, sometime car recoveres, but I usually try to stop (when safe) and car dies. Then I restart the car and it runs as if nothiong happened)

Thank you for your advices!!!

If it hasn't allready been replaced try a new ignition switch.

...a few more details on 94' 850 stalling while driving:
- it happened at speeds from 40-70mph
- recently done tune-up (filters, plugs, cables...)
- recently replaced fuel filter - service said pump was OK
- it burns a lot of OIL (quart / 500miles)
Thanks!

I had small stalling issue sometime ago (not as severe as yours) and it was resolved with a spark plug change. You can sometimes just clean the MAF instead of replacing it. Also clear the batery connections.
If this doesn't fix it, you might want to the stalling thread on http://www.matthewsvolvosite.com/ for more severe stalling cases.

I had the same problem and tried everything. I finally replaced both the ignition switch and the fuel pump relay. No more problem.

I read that the relay can develop a small crack in the solder that can create intermittent issues.

At any rate, that took care of it.

Good luck.