Please help any ideas .?For the past 3 monthsmy Volvo 1998 s70has stalled intermittently while at a stop or below 30 mph.[:@]
There is no check engine light. At first it had a really ruff idle cleaned the throttle body and fix the common air leak by flame trap.Idle got better. it still surges at idle in gear between 500-900. This only happens when you know it is going to stall. Most of the time the car is fine . she is not running the ac and it still stalls.I checked the Van airmeter by unplugging and plugging it backthe car stalls. Check fuel pressure it is good while running and pressure holds at 42 psi. Check resistance on coil checked out good ,and cleaned connections. Reset computer disconnected Batterie and cross connected terminals . Then cleaned connections on computer and replaced. then found broken ground ,fix ground to motor. Had alt/bat checked.I finally just dropped it off to Volvo shop. They did not know exactly what is was ,but they do think itmay be the ac compressor clutch locking up, the S-belt is a little worn , but the idler pulley for this belt was shot.I had the XYZ shop changeidler pulley out .i would think the belt would melt , and you would hear it.

I then checked the compressor using white paint ,and timing light. Is was moving freely off and engaging with ac on , I told the woman when theF ** belt falls off ,then well know .she is not happy with that response.

I still have a squeak ,but have not had time to remove belt and turn everything by hand yet.I need to run car with out belt to make sure the squeak is not the timing belt area etc.

I'm not sure if the fuel pump is going , cam position sensor, v air meter, coil over heating and dropping out,ac compressor, break booster or check valve ,no one is sure... Is there a way to test van air meter, cam position sensor? I maybe cheaper to give her my car but she loves this wagon. Thanks -Jake-

Replaced recently
1.)Fuel pump relay
2.)Fuel Filter
3.) Air Idle control Valve (little noisy)
4.) O2 Sensors Bosch OEM, Before and after CAT.
5.)Air filter,Plugs,wires, rotor, cap
6.) Throttle positionswitch because cruise control was not working and new throttle cable it was cracked. Then replaced cruise control switch on break peddle. Cruse control works.

Replaced 4 months ago
1.) timing belt ,tensioner, idler pulley and water pump
2.) S-belt.,plugs

 

How does the Cam sensor plug look? They start to fall apart with age.

When it stalls does it stumble like it is running out of gas or does it just die?

 

it stumbles, for about 30 more feet then just dies, restart two threee cranks it starts back up again. I was thinking of that too , so Ichecked and cleaned the connector on cam position sensor. Is there a test for the Van or cam sensor i can do?

 

Tech, would the cam sensor throw a check engine light ?

 

Sometimes it does but not all the time.

But if it stumbles then dies I would think maybe the fuel pump is loosing pressure.

Maybe try investing in a fuel pressure guage that you can leave on the car and watch it when it stalls and see if the fuel pressure graudually drops off.

 

I put a fuel pressure guage on it, it has good pressure ,even when it stalls. That is why i replaced the fuel relay.

 

The only way I know to test the Cam sensor is to play with the plug with the car running and see if it stalls.

I don't have the specs home for testing the sensor but I would bet it would test ok.
If it only acts up sometimes then most of the time it would read ok.

 

i think i have the same problem with my 1998 v70 & after looking through these forums, it seems like a common one. I thought it might be a problem that Volvo might fix, but I spoke with a dealership that said it's only an acknowledged problem with vehicles made in 1999 and after, but since I can't get any error codes, I'm stuck with a vehicle that dies after being driven on the freeway (which in LA means I have no vehicle)

Unfortunately, I don't know the 1st thing about cars and can't do any of this work myself, but I was curious about any solutions/insight you can pass along. My mechanic has changed the idle regulator valve, cleaned the throttle body, cleaned the fuel injection...i think this corresponds to all the things that have been suggested in the thread. He is stumped.

I'd love any advice &/or words of commiseration from the community...it seems like there's a lot of knowledge on these boards

Thanks a bunch!
nt

 

had similar problem on 1999 t5, replaced throttle bodies ecu and in the end it was just a o2 sensor....

 

I just replaced Air flow meter.I'll let you all know if that was it or not.

 

I had a similar problem. Car would stallat idle when hot.Eventually, it startedstallingwhile in motion. It got so bad one day that I could not get over 40 mph and it would stall about every 500 feet.

Drove (stalled) it straight to the closest garage diagnostic stated Mass Air Flow sensor, replaced it for 250 bucks and I have not had an issue since.

 

Mass Air Flow sensor it was the issue. I did not have a Check engine light...Sometimes this sensor does not throw a check engine light.

 

Jakesters!
Did that help? I just posted the same issue...
Thanks!
Heather

 

Heather, The first thing i would check on your car is the fuel pressure using a gauge, and replace the fuel pump relay 32.00 if the pressure checks out . This ischeepeer and a Mass Air Flow sensor @175.00 .
The relay for fuel pump is located at the fuse box under the hood ,but you have to remove the torx screws to get to the relays, the top cover comes off.
-Jake-

 

Thanks! I am going to try and find a relay at a parts store some where around town tomorrow. My 740 had to have the relay replaced last year. So I was familiar with the symptoms, have been asking my dad and mechanic if that could be it. I learned from my mechanic that the fuel system usually doesn't provide any codes to the computer. Hopefully this is the issue. Easy fix I can do myslef and cheaper. I really can't afford to put anymore money in this car for a few months.

 

I also have a 98 v70 GLT. had the same problem a month and a half ago. after reading here, I decided to replace the $250 MAF and work very nice until this morning. Before that I made a major tune up by replacing whatever I can, including the MAF cost me over $600. Like I said this morning I'm back with almost the same issue. This time no codes. I can prevent it from stalling by increasing my rpm and seem to run after awhile then goes back again.I'm not really mechanically inclined but I can still do some stuff like replacing relays. Does anyone know if replacing the fuel pump relay will solve my problem? or am I looking at another issue? Would it be possible that my new MAF needs replacing after 45 days? I love the car but maintaning it would be very hard, monetarily if I will be replacingMAFs all the time. Thanks in advance for any reply.

 

You could have a pretty big vaccum leak and it will cause the stalling.

 

Thanks for the reply tech.
Vacuum leak... I would presume it will be from the hoses, is there a way to find the leak or do a test? Or should I replace all the hoses related to it?

 

Usually the easiest way to find a vaccum leak is to have the car running and spray brake clean around the hoses. If the idle changes you found your leak.

 

Thanks again tech. I haven't had the chance to find out about the possible leak. I'm having some good overtime going. Hopefully enough to support my volvo. Will post as soon as I can, will need help in testing as it won't stay on (now).