I have a intermittent stalling problem with my 1996 850 non-turbo wagon. So far it's never happened at freeway speeds, thank God. It seems to occur only when I'm waiting at a light, or am nearly at a stop. It doesn't happen every time I go somewhere, and to date has never happened twice in the same trip. With a turn of the key, the car starts again immediately after stalling.

After checking previous related threads, I replaced the fuel pump relay and the fuel filter. The next step seems to be to replace the fuel pump. But before making that larger investment, I'm wondering if there are alternatives that I'm overlooking.

Some other related notes: I'm in Minnesota, so the weather has recently turned markedly colder. And the CEL is on with a P0410 code — the secondary air system, which for the moment I'm ignoring. Finally, I can predict sometimes that the engine is about to die. It will seem to miss a beat, and then a block or so later will conk out. My question about this as a fuel pump issue is why it doesn't either work or fail completely. The occasional brief failure I don't really get.

 

No other codes? When was the last tune up?

 

Hello TonyS. i had a similar problem with a 94 850. I have a friend who wrenches these and he told me that the cam and the crank sensor are both common failure items. The car I was working on had 335K so everything is old and used. In my case, the problem was the fuel relay, the board was burnt and there were several questionable solder connections. You might check the cam and crank sensors.

Good luck, I know how frustrating this is.

 

I got this from Gdog: To verify it's the fuel pump, take off the access panel to get to it; leave a light hammer nearby in the car. Then drive around and next time it konks out, tap on the top of the fuel pump cover with the hammer. If it then starts right up and runs (even briefly) then you found the problem...

Good luck, and let us know what you find.

 

Thanks for the replies.

To rspi: No other codes. Regarding a tune-up: The plugs and wires were replaced in early summer. I put a new fuel filter on last week. Your note reminded me that I should throw a new distributor cap/rotor on as well, so I ordered that this morning. It would be beautiful to discover that to be the solution. In any case, it's cheap and at least eliminates one question mark.

To jacktoz: The car starts right up again after dying, so there's not really any need to bang on the fuel pump. But thanks. I'll have to do some further research on the cam/crank sensors.

 

You need to watch the pressure at the rail. See if you can rent or borrow a fuel pressure gauge then watch what it does at idle as opposed to higher RPMs

 

I found that removing the fuel pump is easier than an oil change on my wagon. When I opened the fuel pump, some pieces (hoses, clamps, plunge) had come apart, but funny enough I was still driving the car, although with stalls.

 

While searching for additional information about this stalling problem, I came across a note from someone (boxpin, maybe? I forget.) observing that sometimes it may be caused if the wire from the crankshaft position sensor gets too close to the spark plug wires. About the time all this started I had been messing around in that vicinity. I grabbed a plastic tie and strapped the sensor wire as far from the plug wires as possible. Since then the car hasn't stalled. I'm not necessarily declaring mission accomplished, but it's been a week or so and there's been no stalling since then. The virtue of trying this first is that you can do it for the price of a plastic tie. I had already replaced the fuel filter and fuel pump relay, and was about to move on to the fuel pump.

 

This is a message in a bottle to anyone trying to track down a similar stalling problem. The thing about an intermittent stalling problem is that you make a change, the car runs for a while, you think you've solved the problem, and then in happens again. So all the "solutions" I listed above turned out not to be solutions at all.

Recently I found a replacement fuel pump at a u-pull-it junkyard for $9 and threw it in. No change. In fact, a week or so later, trusting the car for a longer drive, I spent some white-knuckled time on the freeway as the car repeatedly seemed to lose power momentarily. I felt lucky to make it back home.

I then read an extensive thread (21 pages, yikes!) on Matthew's Volvo site on engine stall, and did the following: replaced the distributor and rotor with new Bosch parts, cleaned the MAF sensor, cleaned the throttle body, and installed a different ($3 u-pull-it again) cam sensor. The old one upon investigation looked dirty and somewhat scorched. The car runs fine for now. But then it did after all the previous so-called repairs I made as wel. So we'll see. I'm tending toward the idea of the cam sensor being the culprit.

To Boxpin, I hear what you're saying (above) about simply throwing parts at the vehicle. It really seems like an idiotic approach, except that the parts in this case were cheaper than the diagnostic equipment. Of course I might be getting what I paid for with $9 and $3 parts.

If I go a few weeks without another stall, I'll note it here.