V50 Engine 2.0D : Flat Spot, loss of acceleration

[Marmoset]

I'm getting an increasing number of incidents where I'm accelerating quite heavily and the engine seems to hit a dead spot, almost like a fuel/air starvation thing, but it lifts and then accelerates as though it's not just happened. Checked oil levels and they're fine, thought it might be the engine tightening up, no air in the fuel lines, fuel filter not yet due for a change (could water in it be causing this?)

I'm thinking along the lines of a hose collapsing, but which one?

Anyone else having something similar?

Cheers

Richard

[Welton]

Sounds a bit of a common theme according to this other thread...http://www.volvoforums.org.uk/showthread.php?t=30119

If there's a fuel leak then air will get in, sounds like a thorough examination of all the fuel line fittings and connections is needed and in particular a good look for signs of a leak (wet/oily looking area).

It should be one of those nice easy and cheap fixes but may require the owner to pin-point the area rather than let a garage loose in trying to find it?

[Marmoset]

Thanks Welton - will check out the fuel system again over the weekend.

[Reprobate]

Originally Posted by Marmoset

I'm getting an increasing number of incidents where I'm accelerating quite heavily and the engine seems to hit a dead spot, almost like a fuel/air starvation thing, but it lifts and then accelerates as though it's not just happened. Checked oil levels and they're fine, thought it might be the engine tightening up, no air in the fuel lines, fuel filter not yet due for a change (could water in it be causing this?)

I'm thinking along the lines of a hose collapsing, but which one?

Anyone else having something similar?

Cheers

Richard

Richard,

This sounds very similar to a problem I'm experiencing with my S40 TD. It occurs around 2300 and again at 25-2600 where the car hits an apparent flat spot, but with mine there is a distinct sound, rather like the waste-gate opening, and then the car carrys on as normal. It's most noticeable in the first 3 gears after which, momentum seems to disguise it.
The car is on a 51 plate, has 94000 miles and a regular service history. The Volvo garage say there is nothing showing on the diagnostic input which suggests it might be mechanical. Ambient air temps above 20C seem also to precipitate the condition but to make matters worse, the situation doesn't always manifest itself even then. An air leak sounds tenuous. Is the turbo waste gate managed on a mechanical basis only - i.e, 3psi and above, it opens?
Any further thoughts from anybody else would be very much appreciated!

[Marmoset]

I've just serviced the car today and the air filter was probaably the dirtiest I've seen it at 12,000 miles, also changed the fuel filter. This seems to have done the trcik, eengine response is defininately faster and although I haven't done any great distance it does feel a lot better. Might be worth just chaning the fuel ffilter to eradicate this, filter itself was £18 so could be worth doing just that.