No idle help...

[Charlie Smith]

Earlier, Bernard Littau wrote:
> 
> '88 5ktq.  Car stalls when you let off the gas pedal.  Runs fine when one is
> driving and when holding the rpms up.
> 
> I have checked the decel valve, and it appears not to be a problem.  I
> disconnected the large hose, and plugged the hose and the valve.  Same stall
> result.
> 
  [  ...  ]
> 
> My next guess is a vacuum leak somewhere. 

A common failure on this system is the moulded rubber hose that connects
the breather outlet on the block to the metal tube that takes blowby
back to the intake system.  Part # 035 103 221 F is about in the right
place in my parts info, but the picture is different.

The part that fails is about 8" long, and is moulded to have a bend
in the middle, it's about 3/4" ID on the bottom where it connects
to the lower block skirt, and about 1/2" ID at the top where it connects
to a metal tube that runs up to the intake manifold / ISV area.

This part splits on the bottom, leaks air, and you can't see the problem
area right off.  If you start poking with your fingers, you will probably 
make it a lot worse and then the problem will be obvious  :-)

    - Charlie


  Charlie Smith   charlie at elektro.cmhnet.org  614-471-1418  
  http://www.elektro.com/~charlie      Columbus Ohio   USA
  http://www.elektro.com/~audi     photos & technical info

  95 S6 Quattro  -  24 PSI, RS2 6 speed, and other features  
  96 Dodge Ram   -  30 PSI, w/Cummins turbo diesel