I am sure that some one can help me on here, I have a passat 130 TDI and top end is a little sluggish. 0-60 is fine Turbo works ok and is pretty rapid. After 60 it becomes lathargic, put a new belt on last weekend using VAG locking tools and fully locked it up. moved the vernier aboit 1 1/16 of a turn and it made no difference. Took the turbo off this weekend and decarboned the vanes ( how sexy are they) and its made no differnce. Pointing to overboost valve but it was replaced less than 5 months ago. Will it just want re setting?

A friend of mine had a similar problem on a 2002 Diesel Passat - the MAF sensor was the problem. £30 off eBay.

Stick some diagnostics on it...

Ed.

if its the boost dropping off, check the MAF sensor, then for cracked hoses.

If not the actuator arm on the turbo wears causing too much boost so the car goes into limp home mode(no turbo).

many a turbo are replaced with this fault but the turbo actuator arm can just be replaced instead.

I wopuld say MAF sensor if it goes slugish at the same RPM Band ( ie regardless of what gear ) ie slugish past 3000 rpm in all gears.

regards

Agriv8

As above, but also carefully check all of the hoses runing from the turbo to the intercooler, they split on the passat, causing loss of boost pressure and can sometimes be mis-diagnosed as turbo failure. Easy way to check MAF is to unplug it whilst the engine is running, if there is no notable difference with the engine running then the MAF is faulty.

Unplug the maf and try it. If its no different then deffinatley the maf. Theyr very common on them. Dont put a cheapy on it though it wont last 5 minutes. Get a bosch one from gsf.

Big cause of MAF failure is road spray entering the inlet, Rover 75 Diesels had big problems with this until they fitted a simply alloy deflector plate in front of the air intake since then failures are rare.