Intermittent Problem with my XC70
 

Hi All!

I'm new here and at the absolute end of my tether! I have an intermittent fault on my '08 XC70 (D5 SE). I'll try to keep It brief!

On occasion it develops a stutter when accelerating/decelerating, almost like fuel starvation. It will also sometimes just completely cut out leaving me stranded (usually in the most awkward of traffic situations!!). when it does this it will usually restart after 5-10 minutes and many attempts. When it does restart it doesn't usually give me any more problems.

I bought the car from almost new and have always looked after it well, I have it serviced regularly at my local Volvo dealer (who were also the original supplier), they have had it in on 4 occasions now because of this fault. 1st and 2nd time they couldn't find anything wrong, 3rd time they decided it was the fuel pressure regulator so they replaced it, problem recurred and once again they are left baffled.

I work abroad and SWMBO doesn't drive so it does get left for reasonable periods of time without being driven, I've gone down the "diesel bloom" route and this doesn't seem to be the problem.

This is my main tow car too and next time I'm home we're planning a caravan trip to France and I would love to figure something out beforehand.

Hopefully there are some wise heads out there in Volvo-land that can offer some advice....I throw myself at your mercy!!!

Possibilities:

Clogged fuel filter: - change it
Clogged injectors: - Add injector cleaner to fuel and drive the car hard to clear out the fouling. Search this forum to see recommendations for injector cleaner brands.

Go for an hour spirited drive on all types of roads to clear any build up out the engine. Find somewhere with some steep hills to make it work harder. If your using cheap fuel try a couple of tanks of premium.

Does this fault occur when engine is up to full temp and the engine bay is hot?

You state that it restarts between 5 & 10minutes, i.e. when heat is dissipating.

There are a myriad of electrical components/sensors that could also fail due to excess heat causing the engine to cut out.

I would ask on here if there is someone near to you with Vida ( the OE diagnostic system on a laptop) which you can hook up then go for a spirited drive and try to replicate the conditions experienced when it occurs and obtain some live data as to what components are doing what.

Did your garage not provide you with a list of stored fault codes?

As for the fuel filter/injectors opinion I would expect other symptoms of poor running to exhibit themselves if a filter or injector(s) were blocked but I'm no diesel mechanic.

I once had Citroen diesel with a blocked fuel filter which struggled to start, would barely idle and ran like it was on 2 cylinders...all the time not intermittently.

My old man had an Alfa 156 that would just stop. No fault codes, nothing. Took months to find. Turned out to be high resistance in the ECU to fuel pump connector giving a slight too low voltage cured by sand paper and a paper clip to tighten the connect pin.

It would be good to hear the final solution as so many people post then omit to tell what was the problem.

Good luck.

As chap above said - unfortunately it really needs to be diagnosed by reading live data as it is showing symptoms. If it's not fuel pressure then its likely to be electrical.

Given it's a diesel engine, fuel pressure could be an issue (hence the dealer replacing the regulator) but I would expect that to cause fluctuations in engine power rather than stuttering?

A single injector could cause this if it was jamming open - again you can trace this with VIDA as you can disable injectors individually. If this is the case, it could be quietly clogging your DPF as well.

I would also check all electrical earths are sound in the engine bay, around the ECU, and the battery terminals.

Thanks for all the replies guys, really appreciate it. I haven't spoken to the dealer since it was last in (working away) but I'll see if they have kept any stored fault codes. I'll run an injector cleaner through her also (may not be what the problem is but can't do any harm!) It's just frustrating that the symptoms are so intermittent and never seem to display themselves whilst the dealer has the car.

Mine lost power, not stopped, but symptoms were as if the turbo was shut off. Two sensors, an air preasure sensor on the intake and a preasure sensor on the exhaust after the dpf were changed and no problems since.

This only happened while nearly home from a caravan holiday in Scotland and only twice, as I was climbing hills. Fault diagnosed by dealer along with a bill for £420.

Don't know if the info any help to you.

Paul.

You might like to read a thread I have started and have just updated.
Subject is: D5 won’t start when hot, sometimes
Good luck with your problems!
Alec