Surging power delivery

[diffeyp]

Hi All

I own a 2009 S-max with a 2.0 TDCi engine.  For some time now I have been noticing that I get a surging power delivery when the engine is under strain.  I first noticed this when pulling a fairly heavy trailer up a hill at about 50mph.  I just backed off and it went away.  However recently I have been noticing it during more normal driving.

At first I thought it might be the dual mass flywheel, but haven't found anything on the web about these symptoms.  Then thought about the vanes on the turbo, however when I connect a vacuum pump to the actuator it moves freely.  Also when I start the car the actuator is pulled in fully (by the vacuum from the engine) which is what I would expect.

I have had a look at all the hoses to and from the turbo and can't see any leaks.   

I replaced the fuel filter about 25K ago and noticed today that at idle there are quite a few smallish bubbles flowing through the pipe from the filter.

I have no error codes.

If anyone has any thoughts I would be extremely grateful as I don't want to start taking things apart if I can help it.

Thanks

Paul

[johnnyroper]

If there are air bubbles in fuel line I would check out the pipes/seals etc.

Also worth checking/cleaning egr valve aswell as they can cause issues when clogged.

[diffeyp]

Thanks for the quick reply.

Forgot to mention that I have an egr valve plate fitted.

I've had a look at the fuel lines and I can't see any leaks, but do you think it could be drawing air in without leaking fuel out?

[johnnyroper]

Itââ,¬â,,¢s certainly a possibility, have a good check round any pipe clips make sure they are tight,and any O rings on filter aswell make sure they are ok.
Also have a look at the injector leak off pipes.

[mike wilson]

25K for a fuel filter is probably enough.  Lots of contaminated fuel around these days and it only needs one bad tank to block the majority of it.