Hi All, I need some help.

My car (1998 V70 AWD LPT, 222k miles) has stalled on me a couple of times and I don't know what the problem could be.

I had a problem with the car stalling a couple of years ago but it seemed a bit different. Back then, the car always started right back up again. This time it seems pretty reluctant to start. Once I was actually not really able to get it to start again. I was close to home, and walked home, and then came back about an hour later and it started and ran fine.

Also, last time it would stall when coming to a stop. This time it stalls when pulling away from a stopped position. It really seems like a different thing. I think when the car was doing this before it was a vac leak. The PCV system was in really bad shape. Since I changed the PCV stuff and replaced all the vac lines I never had another problem until this week.

I recently did a vac leak test with pressurized air (as described in VADIS) and found no leaks at all.

According to my scanner, everything seems fine with the O2 sensors. Switching at a decent rate and reaching good max and min values.

I of course suspected the fuel pump relay, but then realized that the fuel pump relay was replaced with a brand new OEM relay the day I bought it from the previous owner. I ordered a new one from FCP anyway and it came in the mail today, so I will install it tonight. I'll monitor to see if it makes a difference, but it went 10 days running fine between stalls, so I don't really know when I'll be able to conclude that this was the fix or not.

The first day it stalled, I found that I had assembled the airbox and primary ignition wire sloppily. For whatever reason, I didn't bother to thread the ignition wire under the MAF but instead laid it on top. I suspected that this was a good candidate for electrical interference. I actually thought this /was/ the problem, because since I rerouted that ignition wire it didn't stall again for 10 days... but then stalled again today so that obviously wasn't the problem (though I'm glad I routed it properly).

I tested my MAF by back-probing with my multi-meter and it really seemed fine according to the test procedure I found. I will buy some cleaner today though and see if cleaning makes a difference...


I really hate chasing things that occur intermittently and infrequently like this.

Any advice is welcomed of course.

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1998 V70 AWD->FWD->AWD Turbo 220k+

Thanks for the suggestions folks.

I did a bit of work this weekend, and I'm hoping I've stumbled on the problem and fixed it. Time will tell.

It stalled again on me a couple of times on Saturday before I had a chance to lay it up for a few hours and get some stuff done....

It's definitely stalling when I'm applying the throttle to pull away from a stop.
I have another thread about how my mileage has been bad, and I'm leaning towards a rich stall out, as KlausC suggested.


I replaced the fuel pump relay with a new one (aftermarket) from FCP. I will hang on to the OEM one I pulled out. As I said before I'm pretty sure it's only about 3 years/40k miles old.

I then pulled all the plugs to re-gap them. I had given them a pretty big gap when I put them in, following some advice I'd seen elsewhere. I actually don't think the gap was the problem here, but I wanted to get the car to a 'baseline' state and rule it out for sure, so I gave them the factory gap of 0.75mm.

What was interesting about the plugs, though, is that they were covered in a dry, sooty buildup. This engine is definitely running too rich.


I decided to do a bit more investigation while I had a few minutes. When I cut a hole in the floor to change my fuel pump I accidentally cut the vinyl EVAP line back there. I put a piece of hose over the two end of the hose and was satisfied that it was sealed up (still am), but this gave me the perfect spot to try to pressurize the system forward of that point. According to VADIS you should NOT be able to pressurize the system from the charcoal cannister BACK to the fuel tank (strangely - I wonder why this is?) but that you SHOULD be able to pressurize the system from behind the canister forward to the intake (the check valves and purge valve should hold the pressure).

So I split the hose back near the fuel pump and added ~4psi of air and immediately could hear the air rushing out up front where the charcoal canister is. So I investigated.

I could feel the air escaping up around the top of the canister where hoses connect but I couldn't get it down to see what was going on because the vent hose was too short. So I opened up the wheel well to have a look.


I found a pretty decent sized hole in the EVAP vent hose:





I think you'll all agree that's a pretty significant hole. Obviously that's the cause of my P0442 code!!

There are actually three lines on top of the cannister: one that leads back to the tank, one that leads to the purge valve/intake, and this one that leads to the 'vent' valve/control.


Just to show you where the 'vent' is in my car, I took a couple of pictures of that as well:





It's in a weird spot, actually inside the fender well, where the bottom part of the hood hinges are. Now that I know where it is, I know that there's a noise I sometimes here when I'm stopped at a light idling that I can attribute to this control.



So anyway, I hope that fixing this hose is the end of both my mileage and stalling problems. I'll report back if I have any more problems or in a few weeks if everything turns around.



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1998 V70 AWD->FWD->AWD Turbo 220k+

The bloody thing stalled on me again last night. I let it idle a while in the driveway this morning to see if it was going to act up, and it was stalling just idling there!

I was beginning to suspect the fuel pump itself, and so I hooked up a multimeter to the pigtail under the floorboards in the back, and watched it until the car stalled. My suspicions were validated - the car stalled, pump stopped, with power still at the pigtail. I turned the key off and then back to position II and found the voltage returned to the pigtail for the priming sequence, but I did NOT hear the pump run.

I think I found the culprit. I've ordered a new pump from High Flow Fuel Systems:
http://www.highflowfuel.com/i-4783046-hfp-255lph-fuel-pump-volvo-xc70-1997-2007.html


Luckily(serendipitously?) for me my father in-law is going out of town for a few days so I can borrow his car while he's away.


I'll report back after I get the pump I guess...

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1998 V70 AWD->FWD->AWD Turbo 220k+

Are your spark plugs black? A loose fitting air hose after the MAF could cause you to run rich and flood out.

Klaus
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Did you do your Random Act of Kindness today?

Jadnhm,

You've given me some help with my new 850, so I'll throw out a couple of things for you to think about. I always suspect the fuel injection relay on these older vehicles first, followed by the crank position sensor. Another thing to consider might be the ignition switch, on my 93 940 it would occassionaly not start or act erractically if it started. It turned out to be the switch, which I accidently (or luckily) figured out while chasing another problem.

I agree, I hate these intermittant things, would prefer it to just be dead preferably on my driveway or in my garage.

Mike