Thought it might be worth a shout here to see if anyone had an idea what was up with my car…

It’s a ’98 Volvo V70. Last Christmas we changed the fuel filter as the engine was occasionally cutting out when idle, and I was seeing brief losses in power whilst driving along. After changing the fuel filter, everything was grand.

I’ve started seeing exactly the same problems recently – cutting out at idle, and loss of power. Only this time, it’s much more severe – I limped home tonight, and lost power around 2000-2500 rpm in 2nd and 3rd gear on the way back. After getting home, I started the engine and let it idle – and it immediately cut out. Left it an hour and it fired up and idled no problems.

When it does start to lose power when driving, I find that if I put my foot down, I’ll get power coming back.

I’m thinking atm it could be one of two things:
– fuel filter needs changing again (although I’d be surprised it needs doing so soon). Makes sense if the engine is ok after sitting for a while, presumably all the crud in the filter is washing back out again?
– fuel pump relay is maybe bad – would explain the intermittent loss of power, but I’m not sure why it would be ok after letting the car sit for an hour or two.

Any petrol heads on here care to venture a guess before I have to take it to a London Volvo dealership?? 😕

A sensor of some sort is faulty? Either over or under fuelling?

I’ve no idea though…

Crap/ water in the tank or it could be a hole in the fuel line (drawing air in) had both of these

Hmmm. Could be that – my lambda sensor warning light is on, so engine could be over or under fuelling. Only thing is, I had the MOT on the car done on Tuesday (!!) and the emissions were spot on – I’d have expected it to fail if the car was over/under-fuelling.

I could be wrong though – not a car expert!

Blocked tank vent or failing fuel pump would be my initial guess. You don’t say if it’s petrol or D.

It was an older Volvo, but I had a problem almost identical to what you have decribed, and after two years of trying all sorts of fixes, discovered that it was simply that the fuel pump relay needed re-souldering.

Try looking on Brickboard. As the name implies, it is dedicated to Volvos, and if it still exists, is the best damned car forum you can imagine. Seriously.

could be other things too like mass air flow sensor – would expect engine light for that though.

cant sense the air flow, so defaults to working out rough values of how much fuel to put in by means of other sensors such as engine temp, ambient air temp, throttle position

You really need to get the car running on diagnosis software to see what the engine sensors are seeing and you can work it out from there.

Sensor I’d say. The engine’s thinking it’s in some other state than it is and is fuelling it inappropriately. If it worked at some point then it could be an intermittent fault wiring maybe.

Is it a metal fuel tank? I had similar symptoms (not with a Volvo) with a tank that was rusting on the inside and the rust was clogging the filter.

Some good advice there – thanks! Looks like I’ll have to get it booked in with a Volvo dealer and get the codes read, then go from there.

One other thing I’ve noticed is an occassional buzz behind the dashboard on the driver’s side – apparently that’s a sign of a bad fuel relay on the older 850s, but not sure if the component layout is the same on my V70 (as a ’98 it is the old-shape V70).

To answer a couple of questions:
– it’s a 2.5L petrol turbo
– no idea about the petrol tank – I thought they would be metal by default??

when was it last serviced

changed the fuel filter last xmas doesnt inspire confidence ….

does it have ht leads – that was crippling my last petrol ….

try a good service if you havnt already !

Last service was around a year ago I think – can check the exact date when I get home. Service was done by the old HR Owen Volvo dealership in Camden.

changed the fuel filter last xmas doesnt inspire confidence ….

Why? I had run the car down to ~20 miles left in the tank. As it turns out, that flushed a load of crap into the filter – so got the filter changed (not by a Volvo dealership, but by a fella who’s worked on Volvos for 25 years or so). I thought that all sounded ok – is changing the fuel filter a sign that something is going wrong with the car??

I had the very same problem with my polo. After calling out the Rac and getting towed to a garage it turned out to be the mass air flow sensor at fault. Water ingress in between the sensor and housing. Take the sensor out thoroughly dry it and the housing. Put a light layer of Vaseline over the join and try again.

Worked for me.

Cheers

Some kind of sensor would be my guess; probably not lambda though.

MAF or perhaps a temperature sensor, as you say it stalled on the drive at idle (after driving), but then was fine after being left for an hour….

Or it could be fuel pump giving up.

Fuel pump relay?…. Seems to be a lot about it on Volvo forum

i meant people often only change symptom parts like you changing the fuel filter.

very few of my mates understand why you need to service cars and just see it as unneccessary expense……

foooools

Me thins it’s the EGR valve, Me thinks thats the same thing as others has suggested “mass air flow sensor” but don’t quote me on that.