1990 10vt avant - falls on its face at 4k rpm

[Bares, Vittorio]

Thanks, and also to the listers that responded off list.

 

I checked the WG solenoid hose - it was indeed occluded - which would
explain the over boost. The old rubber hose had collapsed on its self
and was blocking the passage of most of the air.

 

That is now taken care of :-) Gauge shows 1.9, and never gets to fuel
cut.

 

However, the 4k rpm problem persists.

 

I looked for boost leaks, basically looking for oil as I would imagine
that oil vapors would accumulate and exit in any spot where there is a
leak. Nothing of any significance.

 

Then I thought, ok, what if the recirc valve is toast? I have one of the
plastic ones (bosch I believe), plumbed into the IC just below the exit
tube to the TB.

*       I believe boost is measured there, at the exit of the IC

*       I'm theorizing that if the recirc is always open, that boost
would actually still be ok, since the recirc dumps into the hose that
goes to the turbo inlet (not sure about this though).

*       What I did as a test is pull the hose that is used to dump
pressure, blocked the hose its self and the inlet on the pipe that goes
to the turbo. Started the car, then unblocked the hose going to the
recirc valve - motor died.

 

If my understanding of how the recirc valve works, it should be sealed
at idle and only open up to dump pressure when you come off the throttle
(activated by a vacuum line that goes from the IM to the recirc valve).

 

Do I have this all sideways? Or does this make sense?

 

Vittorio -