1993 850 Almost dies at stop

jcoduto · Post by **jcoduto** » 26 Apr 2003, 16:50

850 Automatic

Problem occurs intermittantly. after driving 25-35 mph them coming to a full stop at stop light or stop sign the engine almost dies. tach drops from normal 900rpm at idle to 500 or under then it picks up again to normal idle ay 900rpm.

Before this happened, very infrequently the car would just die. Took it to Volvo dealership. They said there were not error codes showing but they repleaced the injector relay. They said the air filter thermostat was stuck opened. They replaced that as well. The car doesn't die anymore it just drops intermitantly to below 500 RPM after stop as stated in paragraph 1 above.

Took it back to Volvo. They said no error codes were seen. They cant get it to repeat the problem above (paragragh 1). After I picked it up at Volvo, it did the same thing, ie dropped below 500 RMP and felt like it was going to stall...

Any advice?

Thanks

Volvord · Post by **Volvord** » 26 Apr 2003, 17:20

Sounds like it could be the IAC (idle air control motor) this is a small stepper motor that maintains the idle speed. Often they will become gummed up, remove it and clean with a spray solvent /carb cleaner. Another area to look would be the throttle body, these will also gum up and should be cleaned as part of a regular maintenance procedure

dpauto.com · Post by **dpauto.com** » 27 Apr 2003, 22:21

Yes.....sounds very much like an intermittent bad IAC valve. I
AC valve will not trigger fault codes and will not always shut down the engine. But will definitely cause an idle drop.

Dave

93&97 850's · Post by **93&97 850's** » 28 Apr 2003, 10:19

My 93 dose the same thing

volvofan · Post by **volvofan** » 14 May 2003, 14:03

also check the fuel filter. sometimes i expereince dying on start up, and this could be due to the low amount of fuel (getting restricted by a dirty filter) to the engine under initial low fuel ideling (like when starting). It is relitively inexpensive and is good change to make sure the electronic fuel injection systems stays healthy.
hopes this helps.
happy trails.

Elijah · Post by **Elijah** » 19 May 2003, 09:45

Hi, I

iseigel · Post by **iseigel** » 26 May 2003, 06:39

I had the same problems - several issues came up to resolve

1 - make sure you have a good ignition wiring hareness and distributor cap (that's the cheap easy start).

2 - If your oxygen sensor has been out for a while, your cylinders could be full of carbon. Usually this can be chemically removed.

- I learned this when my car failed its pollution inspection last year. Dash ights flickered at low speed - occasional stalls. Now its running much better, @ 172K miles.

Guest · Post by **Guest** » 26 May 2003, 10:27

i think yours probem is MAF sensor

Volsey · Post by **Volsey** » 23 Jun 2003, 02:28

Most all of the other responses were valid conjectures as to the source of your problem. This one may sound obvious, but it was the cause of the same symptoms in my 93 850. Check your intake hose (and other appropriate intake ductwork). It is an accordian/style hose between your airbox and the intake manifold. Mine had a small tear in it (which was overlooked by a mechanic friend) that caused false readings in the fuel/air mixture control system. My car stalled out when decelerating (especially quickly) and coming to a stop. Sometimes it would correct itself when it dropped below 4 or 5 hundred RPM's. GOOD LUCK!