Turbo problem

[mickel2]

Hi, I have just had a problem with my 2001 AVB Passat, on tick over it is smoking blue, I have found that there is a lot of vacuum on the actuator making the turbo run very fast on tick over. Removing the vacuum pipe there is a sucking which disappears and the car ticks over properly with no smoke. Any thoughts please.

[zollaf]

on tickover there should be max vacuum on the turbo actuator. vacuum makes the turbo boost. no vacuum means no boost.

[mickel2]

I thought the turbo kicked in at approx. 1800 revs so why would max vacuum be on the actuator at tick over?

[zollaf]

the turbo works from tickover, you only feel it working from about 1800, but its there all the time because its a vnt not a wastegated turbo. when max boost is reached the vacuum falls and adjusts the vnt to produce less boost.

[mickel2]

My problem is why has it suddenly started smoking blue smoke on tick over, unburnt fuel seems to be the problem. As I said if you remove the vacuum pipe to the actuator it doesn't do it!

[zollaf]

undo the pipe and the turbo stops spinning, so its probably a problem with the turbo. maybe oil seals going. how much play is in the shaft. you are allowed 1mm or so up down movement but none back/forth.

[mickel2]

Very little play back and forth and sideways.

[zollaf]

very little back and forth or none. any movement is indicative of a failed bearing.

[mickel2]

Also I have checked the outlet from the turbo, intercooler pipes and only a slight trace of oil which I believe is normal.

[cyderlover]

Hi
Unburnt fuel equals BLACK SMOKE
Excess Oil in the engine BLUE SMOKE
Excess water WHITE SMOKE
Make sure engine has not been overfilled with Oil this can syphon into the intake & cause high idle + blue smoke on start up & clog up the whole intake & vnt system
High revs & Black smoke when starting was in my case bad coolant sensor telling ECU it's firkin freezing out & it was chucking in loads of fuel hence high revs & smoke if this happens with an overfilled engine you may get the blue smoke as well
On my Passat it was overfilled badly with cheap ****** oil & This oil clogged the engine almost to choke point and eventually found it's way into the CAT & this exploded splitting the CAT & then limp mode for months & months even after initial repairs but with a lot of research on here & other Passat sites the following totally solved my problems
I stripped & cleaned the whole intake system, replaced EGR valve/ shut off valve assy + all associated bits with Allard straight through alloy pipe(£40) repiping the vacuum connections, WD40'd the VNT actuator every day hot & cold replaced std green coolant sensor with black bodied one (Audi updated type £20 from GSF) modded airbox the same as my Golfs , alloy catch tank on the crankcase breather system (eBay £16) & a Powerclick modded ECU (eBay £65)and now my 1.9 TDI (ATJ) Passat is no longer an VW estate that I can cycle faster than it :-((( goes but something a bit more like my Modded Golfs used to be for less than £150 in total including all gaskets etcetc
FUN but without the high petrol bills ;-)
Hope this helps you & others sort their probs out
At one point I was going to scrap the old shed on wheels but now the driving fun factor Quotient has increased exponentially