power loss

[mrchimps]

so driving the mrs to work this morning and go to overtake some traffic. Start to overtake no problem then feel a loss in boost, almost like the turbo isnt there. no smoke pops bangs or lights on the dash. car seems to drive ok just no boost. can hear it whistling as before maybe a bit more when accelerating.

1.9 tdi avant.

any ideas or help appreciated

 

[mrchimps]

Just took it out again after switching off and its fine now. presume this is an overboost problem?

 

[Mike.M]

Sounds like sticking turbo vanes to me. When cold, move the actuator arm its full cycle to see how stiff it is.........should be smooth and have full travel when pushed on.

 

[mrchimps]

ok, will give it a try its banging hot at the min, so will report back in a couple of hours.

if it is sticking vanes, can this be rectified?

 

[Mike.M]

Sticking vanes is basically where there is too much carbon build up in the turbo, preventing it from opperating as it should.

The proper way to do it is to remove and manualy dismantle the turbo to clean it inside.

Mr Muscle clean method has been done by people but is a temporary fix (depends on severity of carbon build up inside) but if you just pot about in a TDI and not give it welly from time to time to keep the vanes from sticking, it will happen again.

 

[mrchimps]

cheers will have a read up

 

[desertstorm]

This is issue can be caused by other things such as a duff MAP sensor, I replaced 2 on peoples cars at work one a Passat and the other an A4.
Can also be caused by vacuum leaks and N75 issues.
The best thing to do is to do some diagnostics with VAG-COM to see what codes are presenting and do some real time measurements .
If it is that the VNT mechanism is sticking and is coked up the best thing to do is to remove and strip the turbo, the Mr Muscle type cleaners are usually only a temporary solution.

Karl.