Ok, so I've got an 850 non turbo with 210,000 miles on it. It's decided it wants to start stalling out at the occasional stoplight. Yesterday it did, I got it to limp back home, it ran fine while i was on the gas, but when i let off, it idled at about 500rpm. So i thought I'd check the plugs and they were quite old, so i replaced them. I put new bosch +4's in, and started it up, it ran well so i pulled it out, and called it a day. So today it dies on me again, at another light, after about 10-15 minutes of driving. I tried twice to start it with no avail, but it did on the third try (about 10 seconds from the time the engine died). Then it was fine and I got home. Now i'm wondering if you guys have some suggestions on what it could be. Someone said that the fuel pump/relay could be bad, and i have yet to jump it to see, but would the relay really reset itself after 10 seconds? Also, wouldn't it die while running and not just idle?

Yesterday, when I got it home and got the plugs out, they smelled like gas. And when i ran it today it seemed a bit rich.

BTW, there are no codes...

Anyone know where to start?

Hi,
- fuel pump relay; yes 15years old, low rmp is low voltage and lost contact but 50$ and 15min replacement only. quite possible one, time to do for reliability
- vacum hose leak, yes but check also pipe from air box to TB for cracks
- TB and IAC clean, yes
- MAF ? never had any broblems with yet
br tapsa
2x850-94,v70D5awd-05

"Yesterday, when I got it home and got the plugs out, they smelled like gas. And when i ran it today it seemed a bit rich."

Sounds to me like it could be your MAF dying or could use a cleaning.

Drop by the auto parts store and pick up a can of MAF cleaner. Remove the sensor from the airbox (there are 2 T25 screws at the back) and spray the element inside with the cleaner. Let it dry for an hour or two and reconnect it.

Update: Being only half-retarded, i decided to check the haynes myself and noticed something aptly called "idle air control valve" and thought, this might be it. Not fully knowing what it would do if its broken, i looked it up. I found that many people have experienced my troubles if theirs went, and i found two possible solutions for this. A) Replace (new for 240, used for 40) or B) clean and see what happens. I went with B first, so I was going to take it off and clean it. I struggle with those spring clips (why they don't use those screw clamps puzzle me) and finally get it off. The inside of it is black. I blast it with brake cleaner a few times and find that the insides are actually not black... Could it be that my IAC had become so dirty that it would stick on ocassion, thus causing the car to stall and die out? Put it back in, and it appeared to run fine, but i only drove it about 5 minutes.

With regards to the MAF, wouldn't that being dirty only kill emissions? I'm going to drive the car tomorrow cause i'd prefer sunlight if it breaks down...

Also, assuming this is my problem, would it explain the car not starting for 10-20 seconds after it stalled out?

I cleaned my IAC with a toothbrush and half a can of TB cleaner, it helped.

Then I started to look for vacuum leaks. Check the vacuum tree for missing plugs, make sure the air hose from the air cleaner to the TB is not cracked. Check other vacuum lines for leaks. A vacuum leak will make the engine run very rich.

A poor MAF (mass air flow, measures the amount of air passing through) can cause driveability issues, usually a poor idle.

Klaus
--
Proud owner of a 220S. If I had more room, I would have more Volvos.

OK, it died again when it came down to idle.

I didn't get a chance to drive yesterday, and started it today. Gave it a minute or two to warm up (obviously not long enough to get it warm) and started driving. When it got warm, i thought i'd check it to see whats happening, so i pulled off in a parking lot, and it stalled out and died. Started it up, stalled out again. I tried it a third time, and it started up and stayed good for me for the rest of my errands ~30 minutes....

I haven't cleaned the MAF yet, but i think the two of you agreed that it would cause poor idle, not stalled out...

Someone mentioned that it might be the Oxygen sensor, saying that the computer might run on defaults and then once it warms up, it would try to check it and if it was faulting, it could screw up idle and die. Now I would have to think something like this would leave a trace, no?

Also, is there any way to check the IAC to rule it out as good or bad? Like if i pull it out and give it charge, it should do something? Or should I get another and see if the problem persists. The only reason I'm apprehensive on doing that is I'd by used one so it too could be bad...

Any other suggestions on what to try?

If the IAC gets too dirty to move, then it would be consistantly bad. A good cleaning with carb cleaner should resolve any problems. But, I doubt the IAC is bad, usually that happens when the AC is causing the idle to fluctuate a lot.

I still think the engine is running too rich. The MAF could be at fault, as well as a dirty air filter. Please look for vacuum leaks which will make the engine run rich and cause stalling at low rpms by fouling the plugs.

The next time it stalls, take out a plug or two and inspect it for wet and black.

Have you tried running the engine above 3,000 rpm (warm) to clean off the exhaust valves?

Klaus
--
Proud owner of a 220S. If I had more room, I would have more Volvos.

Ok, looking at the car i found no obvious vacuum leaks. Got the gauge out and found that it was about 20" +/-.5"swing... That seemed much too constant for their not to be a leak.

I also pulled out and cleaned the MAF put it back in, and as of yet have to experience a stall. Tomorrow will come the test, because I think some of it has to do with starting from cold, but i don't really know if it matters... Also, while I was doing this I pulled off the air filter case, and I think I might have pulled out a line. The top back of the cover has two hoses outta it. One appears to be a vacuum line, and that's still connected. The other one is a harder hose, and isn't connected to anywhere now. Is this supposed to just hang down, and be like a ambient hose?

The plugs were already quite black (they have <50 miles on them) so its been running rich..

Thanks for your help...

There are no ambient hoses around the engine. I don't remember where that hose goes to. But the attachment is less than the hose length. And it must attach to something! If it is large, it could go to the idle air control or down to the pump below the battery.

Klaus
--
Proud owner of a 220S. If I had more room, I would have more Volvos.

I decided to drive it out and had one problem on my return journey. I came to a stop and as soon as I stopped, the engine dropped to ~300 rpm for a moment then came back up and was fine... Don't know if it's symbolic of not fixed, or the hose I unplugged... It didn't seem to be as rich as before, though it was still pumping mist, and smelled faintly like gas. I don't really know what the next step would be to check, any suggestions?

The hose appears to be a metallic hose (rather than the pvc that the vacuum hoses appear to be made from). It is significantly smaller than the other hoses, I'd guess 1/16" on it.. I'll investigate tomorrow when its light again.

Drove it today and haven't had a problem. When I got home I pulled out a plug and it seems almost completely clean. So perhaps its no longer running rich, but I don't know for sure..

I cannot figure out where this hose goes though. I haven't taken off the air box yet, because it looks like its going to suck. The hose comes off the air box and goes about 4 inches before it hits a connector. Then it is a hard plastic hose that runs about a foot, and its bending appears that it goes under the air box. On the inside of the airbox there appears to be plastic covering where the vacuum hose and this hose would enter. When the engine is running there appears to be no flow through this hose. When the engine was off, i tried blowing and sucking through it to find that air would move both ways. The air faintly tasted like fuel.

If anyone has an idea where the hose goes can you let me know? I can post a picture of it if that would help, but i don't know if it would be beneficial.

Also, I've been reading various site on this and some people say that if there's puffing coming out the oil dipstick it might be the PCV system. Does this make sense, is there a way to check it, or just replace after so many miles?

Yes, a dirty IAC will definitely do that too. Research pays off! =)

A dirty MAF will cause it to run and idle horribly, but most likely you'd have a lack of power or stumbling associated with that on acceleration, which it doesn't sound like you're having.

It shouldn't cause a starting issue though, at least I wouldn't think.

Does your temperature needle always stay at the 3:00 position once the engine is warmed up?