95 855 Turbo stalled 2x in 2 months

spatt · Post by **spatt** » 29 Mar 2010, 08:27

Before I go purchasing parts that I don't need, maybe someone can shed some light.

Driving to the airport about 2 months ago, the motor seemed to rev itself a bit and I started decelerating. It kept running and after slowing about 20mph I kicked the accel pedal and it took off. Exhibited no problems after that for about a month. At the beginning of March I drove it to pick up my S4 out of storage and left it over night in front of that house. Next day I went to pick it up and drive it 2.5 miles home and it exhibited the same behavior with .5 miles to go, but this time stalled out. I put it in neutral and it cranked strong, but no fire. Got out to tell my bro-in-law to push, got back in, tried again and it fired up. Now again, no problems since, albeit I haven't driven it a whole lot besides one more to-and-from airport.

Talked to my dad about it and he said he had a car a while back that the ignition module was going on that did the same sort of thing, so that is my best guess. Car runs fine otherwise, pulls strong. When I got it in August I did new IPD 8mm wires, cap, rotor, plugs, PCV and trans position sensor.

Thanks in advance.

Post by **jblackburn** » 29 Mar 2010, 08:50

It could be a failing cam position sensor, which in turn controls the ignition coil. It is hard to tell unless you can get it to act up a little bit more. There is a chance there are pending codes stored in the computer, even with no CEL.

Have you tried seeing if there are any codes stored in the OBDI boxes?
http://www.volvospeed.com/CheckEngine.php

spatt · Post by **spatt** » 29 Mar 2010, 11:18

Thanks, checked the codes and got:
4-3-5 Front heated oxygen sensor - slow response.
4-4-3 Catalytic converter efficiency.
in A2, nothing in A6. I'm not 100% on O2 sensors, but I thought they would just cause poor fuel economy, not stalling.

Post by **jblackburn** » 29 Mar 2010, 12:55

No, the oxygen sensor won't cause the car to stall, but it sounds like you've got a vacuum leak that's making the O2 sensors mad. That may very well do it. Look at the elbow behind the PS pump with a flashlight - that's one of the most problematic ones. While you're at it, it wouldn't hurt to clean the mass airflow sensor as well, they can cause stumbling and stalling problems as well.

Those are the cheap (money-wise) things to check out first. Vacuum leaks can be kind of frustrating to find, but if you can't visibly find anything, spray around with some carb cleaner and listen for changes in the engine noise.

spatt · Post by **spatt** » 29 Mar 2010, 14:30

Great, my vac lines are all in need of replacement anyhow, guess I'll get on that first.

One thing when I replaced my PCV, the connection labeled 13 in this image was supposed to go to the pass side of the intake, but my intake had a disk there with no nipple to connect to, and I can't remember where the old one went so I capped it off.
http://www.fcpgroton.com/product-exec/p ... gory_id/63

Post by **jblackburn** » 29 Mar 2010, 18:50

Your car has EGR, doesn't it? I know there is a different kit/routing for the PCV system in the cars with EGR, but I'm not sure at all what is different between them and the PCV routings. The only one I have worked on is my S70, so I learn bits and pieces about the older models as I stumble across them.