(Fwd) RE: Erratic Manifold Pressure: Please help

["Renier Meyer" <RMeyer.rdi@reutech.co.za>]

Thanks to all who responded to my plea for help.

To make sure that I was looking at the actual manifold pressure and 
not being fooled around by the WGFV, I disconnected the WGFV and 
bypassed the function. 

The boost is controlled by two valves and the WG is set to open at 
2.0 bar. The erratic manifold pressure starts happening from 1.2 - 
1.4 bar.

The WGFV under normal conditions starts modulating when reaching the 
the boost setting in the ECU eprom. 

To me the problem sounds purely mechanical, but in order to talk the 
language of the mechanical engineering people, I need as much 
background as  I can get. Any help or suggestions welcome.

TIA

Renier Meyer
89 200T Durban South Africa.
84 100 (Wife's)






Rob wrote:

My car does this also (91 200Q). I thought it was just the WGFV working,
opening and closing the wastegate.

Rob Winchell
91 200Q
87 4kCS

> -----Original Message-----
> From: owner-quattro@coimbra.ans.net
> [mailto:owner-quattro@coimbra.ans.net]On Behalf Of Renier Meyer
> Sent: Wednesday, May 13, 1998 11:33 AM
> To: quattro@coimbra.ans.net
> Subject: Erratic Manifold Pressure: Please help
>
>
> I have problem creeping up on me again. (89 200T)
>
> Whenever I boost higher than 1.5 bar, the analog boost gauge goes
> crazy. It oscillates between 0.1 - 0.2 bar higher and lower than
> the current
> reading.
>
> If the car is slowly accelerated, it sometimes happens from 1.2bar.
> The car goes well, but obviously looses power when this happens.
>
> The head has been redone about four months ago for the second time
> , where they found a valve sleeve that was loose on No1 cylinder.
> The symptoms was an occasional puff of smoke so bad that you could
> not see the traffic behind you.
>
> The first time the head was done, they replaced bent valves.
> These bent  after loosing a timing belt when the waterpump
> bearings seized.
>
> The car was done by a reputable firm, under supervision of the local
> Audi agent. All bits that were worn got replaced, and they checked
> the motor very carefully (or so they say).
>
> I can see the same symptoms as before the oil started getting blown
> out. For the first three months the pressures were fine, and the car
> really pulled well.
>
> Questions:
>
> Is there any way that I could have caused this, say by running higher
> boost than normal? (The higher boost was first done by a vacuum pipe
> mod to the WGFV, and now with a carefully tested remapped ECU eprom).
>
> The car is driven up a steep hill just after start-up. Could the oil
> drain away from No1 cylinder be causing this?
>
> Is there any test that I can carry out without stripping the head?
>
> Any way to fix this? The job is still under guarantee for the next
> seven months, but I would like to get to the bottom of this and have
> it sorted out once and for all.
>
> The detail mechanical side on this issue is a bit beyond me at this
> stage.
>
> HELP OR SUGGESTIONS DESPERATELY NEEDED, private or on the net
> is fine.
>
> TIA
>
> Renier Meyer
> 89 200T Durban South Africa.
>
>