Resident TDi expert?? I have a question..

[ewenmaclean]

thanks a lot for that explanation - much more complicated than I knew then on the newer models - apologies for erroneous comment - useful to have an expert on all of the various incarnations on here! I'll keep my mouth shut unless I'm sure it's the non pd engines we're talking about...

[toomanytoys]

Yeah - brake cleaner recommended or Mr Muscle as Lloyd says - can't think of much he hasn't done so that's a good tip

Sorry to be a pedant but a tdi technically doesn't have a throttle. That's why diesels need vacuum pumps. If you're referring to the anti-shudder valve then it functions as a binary throttle - completely free when running and blocked with ignition off - designed to prevent runaway. Worth checking its operation while you're there for sure though.

The flaps close partially when driving now to cause suction in the inlet so EGR will flow more....the Egr valve, throttle valve and egr change over valve are 3 separate parts....my money is on the change over valve on the back of the engine which incorperates the cooler, some are electric and vacuum and some are just vacuum operated, I suspect it's got both on a 2007 passat...it's a major pain to change it and needs a visit to the dealer for the software adjustment to prevent future carbon build up ( doesn't stop it going wrong in the other 4 ways of course) unless you like struggling up the back of engines I would suggest hiding if these jobs come your way!

BALLS no I don't like fannying around up the back of engines.. bad enough in the back of the doka.. ha ha ha....