Misfire/surge under load, fluttering noise

[vinnie808020]

Morning all, looking for some advice.

I recently became the proud owner of a 2005 (55) a3 2.0t quattro. It is completely standard. There is an issue with a miss/surge under acceleration where the car almost feels as if it is jumping, the revs stay consistent with no visible change in the rev counter, I have also noticed a fluttering noise when driving at normal speeds (60 mph). I have changed the spark plugs and air filter as a matter of course also had a diagnostics on that show no codes.

Any help will be much appreciated.

Thanks

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[prt57]

I think I would be checking the diverter valve. Unfortunately, with the K03 turbo it is bolted onto the housing. Totally doable dependent on your mechanical skills and tools. So with the hassle of getting the old one off I would just fit a new one anyway. At that age if it still has the original valve it will have a rubber type diaphragm which can split. The latest fit and forget version has a plastic valve but some can leak a little boost even when brand new. The best sealing version is a revision G. This also has a rubber diaphragm but is stronger. I fitted one of these to our TT 45k miles ago and no problems since.

 

[vinnie808020]

Thank you for your reply, I have some diy mechanical skill, am i right in thinking that the dv is located on the drivers side, Jack up car remove wheel and arch guard and access the valve from there?
Any recommendations on where to get the part?

Thanks

 

[Daveyonthemove]

I had a similar lack of power when i got my S3 a few months ago.
After running plenty of logs using Torque and getting consistently low MAF readings I checked the DV and found it was an old valve that had a split.
Replaced it and the car came alive again, roughly 50bhp gain straight away.

 

[vinnie808020]

Thank you daveyonthemove, it seems that the dv is definitely worth checking over and replacing, fingers crossed that will be the fix.

Thanks for your reply

 

[vinnie808020]

Update,

Car was serviced and had the dv changed today at last! Unfortunately there has been no change, the surge is still there starts around 2500 revs and keeps happening as the revs increase, had a diagnostic when serviced, no fault codes were found.

I am at a total loss at what to look at next, any suggestions are most welcome.

Thanks

 

[SootySport]

Fuel pressure not up normal? Do you have a loud ticking noise? Which sounds like a noisy injector, this could a simple fuel pump cam follower worn out, it’s regarded as a regular service item now.

 

[prt57]

If you are anywhere near Nuneaton there is a company called RTech. They are very well known for their remapping skills but they also specialise in diagnostics and getting things running correctly.

 

[vinnie808020]

Thank you both for your replies.

@SootySport, there isn't really a loud ticking noise that I have noticed, is the fuel cam follower a diy fix?

@prt57 thanks for your suggestion of rtech I'm not a million miles from Nuneaton so definitely worth considering.

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