[Vwdiesel] 01 Golf TDi TURBO issues

[LBaird119 at aol.com]

In a message dated 7/7/2010 12:21:56 PM Pacific Daylight Time, 
rbp at 4u2bu.org writes:

> but not if the turbo's not functioning, correct?

  But there's nothing to indicate your turbo has QUIT working is there?
The controls for it may not be working properly but for IT to not be 
working would require it to not spin, physically break (really bad) or 
in the case of a VNT, the vanes not move, yet it would still spin and 
produce boost.

> 
> mine is not now, and has not been since the alternator 'repair'
> no way to know when in the course of events it was disabled, but it's 
> possible that boost was weak or non-existent at the time the pipe was left 
> disconnected
> in that case, intake suction could have been more of a issue, correct?

  Still NO!  You're not sucking rocks, small animals and such into the 
engine!  Sheesh!  Back in the 50's and such a lot of people ran around 
with non existent, lousey or bad air filtering setups.  The engines didn't 
die in 50 miles.  Unless your idea of driving it hard was pulling broadies 
in a sand pit...

> 
> (for the record, though, theoretically the majority of the energy of the 
> expanding combustion gasses goes into pushing the piston down, right?
> and the better/more efficient the engine, the more completely that energy 
> is spent
> so the upstroke to exhaust, while expelling hot gasses, shouldn't be 
> fighting any real pressure from sill-expanding fumes, should it?)

  Uh, I think the amount of energy that goes to turning the crankshaft is 
something like 25% to 28%.  Not positive but it's roughly a third to 
power, a third to waste heat and a third to friction or something like 
that.
  You'll still have resistance from the exhaust stroke.  You're pushing 
a 3" hole of "air" through a 1" hole with an inverted tulip/mushroom 
hovering a few ten thousandths of an inch above the opening.  
Incidentally a turbo converts enough heat energy to rotational and 
pressure energy that it drops the temp by 100 or 150F across the 
turbine.

> 
> yea, unless it's not working :(

  But you need to find WHAT is not working.  Your turbo's boost is 
controlled by a bypass valve (wastegate) that lets exhaust flow 
around the turbine.  It'll still turn but not create any real boost.
That is controlled by an actuator, which is controlled by a solenoid 
and hoses to and from and likely another solenoid and hoses to and 
from.  The solenoid is controlled by the computer, which gets its 
info from several sensors, some via hoses, some via wires.  Any one 
of those being broken or bad would cause a loss of boost.

> 
> 
> anyway, all that said, I am thinking the best place to start is simply 
> replacing lines
> several people have said it's hard to see/find leaks, and the turbo simply 
> not working since the repair seems fishy
> who's to say they only left one thing disconnected?

  In that case you don't need to do like a shop that doesn't know 
the car and just start replacing stuff.  Spend the money on a 
Mitee-Vac instead and start TESTING hoses or such.  A simple, 
physical inspection can do wonders.
  Dad's Passat had been in to the dealer SEVERAL times for loos of 
power/boost.  It finally got traded in, likely for that very reason.  He 
bought it and we found out why it'd been traded in!  I later found out 
the dealer DID have the service records, which confirmed an ongoing 
problem.  Their service manager (way younger than me)  :-P  suggested 
I replace the turbo and run some premium diesel in it.  :-P  One of 
his techs dismissed his suggestion of replacing the turbo.  I DID find 
out that the boost sensor was in the computer though.  I followed the 
line, found a kink and viola!  The problem was fixed!  You have to 
look, research, ask, etc.  I'd checked several other things, like the 
actuator, etc. first.

> 
> any advice on what tubing to buy and where?
> 
> thanks again, all
> Rolf in MA
> 

  First find out if you need any tubing...
    Loren