The engine on our 1999 Volvo V40 is playing games, started on Friday, the engine randomly goes upto 3-4k revs and stays there for 10-20 seconds both whilst idle and driving (whilst in gear it accelerates). Last night it died whilst pulling away from a junction, revs were high at the time so it could of stalled as they dropped and I didn’t counter? it wouldn’t restart until this morning although I may have flooded the engine trying to get it going again.

I think I may have located the problem, a hose was pretty loose and I’m guessing too much air is sucked in but tbh I’m not that clued up on engines.

Below is a picture, I have put some blue insulation tape round it to try and seal it better and see if that’s the problem, I’ve just had it running on the drive for 5 minutes and the problem hasn’t re-appeared. So is it likely to be the hose or something else (throttle cable, sensor)?

Hi, I have a 1998 2.0 V40 so am quite familiar with these cars.
Don’t think my car has the hose that yours does. Is yours a turbo by any chance, or a std 1.6 engine?
Just had a flick through Haynes manual and there are no pics that look like that hose in the book.
I think the hose is EITHER an air inlet hose or air intake for turbo (if fitted).
The main air intake box is to the right of your picture, thats the big chunky ribbed hose that comes out of it. There is a temp sensor on that hose, right on the bend. Does the hose with the blue tape on go anywhere near joining onto that?

Loose air hoses make cars go mental, so that may be all it is.

Holler if you need more help.

CHB

Does that damaged metal hose go from a sort of heat shield over the exhaust manifold to the air filter box ?
If so, I’ve not seen one on a fuel injection engine before, I thought they were only used with carburettors. It’s probably just to get some warm air in to the intake to help vapourise the petrol. It’s not critical to the running of the engine.

sounds like an air leak or idle control valve sticking

Yes the damaged hose feeds into the air filter box.

I’ve just taken the blue tape off and went for a drive around the block after leaving it running idle for a few minutes, the problem didn’t return so I guess the broken hose isn’t the problem.

Intermittent problems do my head in, either be broken or work grrr….. don’t fancy it returning on my snowy country lane commute tomorrow morning.

In that case the damaged hose is warm air inlet, same as mine, but different routing.
If you want to check it’s this then unclip the four clips that hold the air filter housing lid on (you might need to undo the big jubilee clip on the ribbed black hose). Remove the air filter. At the bottom of the air filter housing there is a flap that adjusts for cold/warm air. The damaged hose should feed into the warm side.

Yeah it is CHB, cleaned out some broken bits of the hose from the air filter box at the same time.

Cleaned out the Idle control unit as Nick_Christy suggested, it was filthy (used this as a guide):
http://s40concepts.net/forum/index.php?t=msg&th=9231&start=0&rid=&S=e2401560d29584cf438a95bce8ddae0f

I’ve also lubed up the throttle cable and so far all is good, took it out for a few miles drive and had no problems.

Hopefully that’s it all sorted, I guess time will tell.

Thanks everyone!

While you are at it, put some silicone spray on the flap in the airbox. Mine used to stick. If it sticks and keeps letting warm air in then you have a massive loss of power. The plunger that operates the flap gets tired with age too, I think mine is on its way out as sometimes the flap is not closing off the warm air properly.
Have you had any other problems with the V40? Had mine 8 years so have fixed most things on it (not that much goes wrong with these!) I guess yours is a 1.6 then?

Sounds like the idle control valve, as already suggested above. My Fiesta had the same problem intermittently. Some mornings I could drive it in 4th at 30 mph with my foot off the throttle.
Whipped it off, cleaned it and it was fine. Had the car for another 2 years and problem didn’t come back.

Ford wanted about £200 for a new valve!

I’m back, the problem returned whilst I was nipping out for some milk. The engine cut out after the revs started increasing on there own. Had to jog a mile home, its nippy out there…

CHB, its a 1.8 (non-turbo).

The engine management light has also come on now 🙁 one other thing that happened is the main fan stayed on and was still on when I decided to leave it and come home (5 minutes maybe).

As I’ve given the Control value a clean and used some STP stuff on it, could it just be knackered? I have full AA cover so will get them out in the morning and see what they say, but don’t fancy sitting around waiting for them this evening.

Have a post here:
http://www.volvoforums.org.uk/forumdisplay.php?f=17

Good forum and one that I use a lot (same user name).

I doubt the car is knackered. Normally major symptoms that are intermittent are not that hard to fix once the cause is found.

Check your crank case breather hose is not blocked by emulsion of oil, with all this cold weather I have known it cause all sorts of problems that are solved by cleaning it out and cleaning out the main butterly valve in the inection inlet with Redex or similar on a cloth.