My car just hates me, I know it!!!

[Gerard <gerard@poboxes.com>]

Hi!

Well, I'm going to take advice from the list and from friends and
first have my auto tranny in my 200t serviced. If any faults start
occuring then the best would be to replace the tranny with another
auto tranny. I would really like to put in a manual in the future,
but time- and money-wise it doesn't work out well for me. I should
just keep my eyes open for a scrap car of the same year. On that
topic I have one question: would a 4-speed auto or 5-speed manual
from the 100 from '92 onwards (ie. post-44 car, A6 shape thing) fit
into the 200 from 1990?

Now, about this post. Today I took my turbo into the VW/Audi agents
to have them see if they can find a fault with my boosting problem.
I wound up 30 km away from home and wandering around a shopping mall
from 9am to 2pm waiting for them to have a look at the car; I saw
"The Full Monty" and "In & Out" (with Kevin Kline and Tom Selleck). :)

The problem: I can give good gas and the boost will run all the way
up to 1.5 - 1.8 bar (as of today) in a car with a 1.6 bar fuel cutout
and 1.4 bar spring, I can make this happen several times a day, it would
seem boost is building to quickly or not being regulated properly
and the fuel pump cutoff will happen. The guys at the agents told me
that they've never seen a Audi Turbo f*ck off like this one. They
have been hammering the car all morning by slamming the gas pedal all
the way to the floor. At 3200 RPM the turbo really pulls and the guys
don't lift off the gas. The car goes all the way up to 120km/h before
the guy backed off the gas and the fuel pump never cut out. They
reckon the WG is probably faulty in some way, but they didn't check
it to see if the excessive boosting was related to the WG having some
sort of stuck condition. Replacement unit is $2000! They said they
couldn't test the WGFV, which I suspect is causing the problem (ie.
boost builds too quickly, not being regulated properly and triggering
the fuel pump cutoff).

Anyway, I'm driving home this afternoon after talking to the guys at
the agents and after they say that the car seems to be running fine
now and not cutting out (perhaps it needed a massive run like they
were doing in order to loosen up a possibly stuck thing somewhere).
I'm going along the highway past some roadworks and then pulled out
into the fast lane and gave approximately 2/3 throttle.... bang! the
fuel pump cuts out! I backed off and drove another 10km or so and on
the way I did some throttle hammering to check. Within about 100m of
testing I managed to have the fuel pump cut out on me 3 times.
Honestly, back at the agents they were doing more hammering than I was
on the throttle and the thing didn't cut out. But with me in it and
with me pussy-footing it about (ie. not planting the throttle to the
ground, but giving about 2/3 to 3/4 throttle gently [no hammering])
the car will build indicated boost quickly and then cutout! And it's
not a matter of huge accelleration either, this happens when the
machine is accellerating mildly.

I swear, my car hates me and is fooling with me!!!

There are several things on my mind:

	1. WGFV faulty.
	   I will leave all tubing in place and disconnect the ECU
	   wiring plug from the WGFV. That should indicate 0% duty
	   cycle which means only atmospheric pressure is applied to
	   the WG via the pressure/vacuum line from the inlet to the
	   turbo impeller.

	2. WG faulty.
	   After testing (1) I will disconnected the tubing to the WG
	   and check to see if boost exceeds the spring rate of 1.4 bar.
	   How do I test the WG operation air feed? My IC-IM hose has
	   just about double in thickness after I repaired it and I
	   understand that on the new IM the ISV and WG operation
	   (lift force?) was obtained from inlet air running through
	   a tunnel in the IM. Could it be that my thicker hosing has
	   somehow stuffed with this air feed along the tunnel and is
	   not providing enough force to lift the WG as boost is
	   regulated?

	3. Blocked pre-turbo inlet to WGFV hose.
	   That is, the WGFV can't vent off boost pressure from the
	   rear of the WG.

	4. Faulty pressure sensor in ECU.
	   How to test this? Bicylce pump onto the pressure line?
	   The electronic dash gauge reads fine, ie. 1.6-1.8 (absolute
	   max!) comes up and the pump cuts inline with what is set
	   in the ECU. I was thinking along the lines of the pressure
	   sensor in the ECU responding too slow and too late in order
	   to do any regulating of boost pressure.

	5. WOT switch.
	   It is the only unit I have and don't have a 2nd hand supply
	   of the stuff and don't want to fiddle with the switch just
	   in case my fumbling hands mess it up completely. My thoughts
	   here are as follows: in conjunction with a stuck WGFV, a
	   faulty WOT switch (no signal indicating WOT) does not
	   trigger the ECU boost management feature, therefore pressure
	   is always applied to the WG through a stuck WGFV without
	   any regulating going on. How can I test the WOT switch
	   while driving? Anyway to wire up a diode or meter to the
	   switch and monitor it from in the car? Same for the WGFV.

My next bet is to take it to Alpine Developments, the turbo installation
people and see what they can find. The guys at the VW/Audi agents told
me that would be wise. But I can already see the Alpine guys telling
me "go to the agents". I've spoken to some aftermarket modifiers and
they all say they don't want to deal with the Audi cars.

Maybe the best thing to do would be to disconnect the WGFV, put in a
new chip (as is the plan, but it will probably never happen due to all
the shit I am getting from the car from wastegates to gearboxes!) and
stuff in a new WG spring to hold 2.0 bar of pressure with the ECU
set to maximum of 1.99 bar. That way all boosting the WGFV was supposed
to do on top of a 1.4 bar spring will now be replaced in a purely
slap-stick fashion by a 2.0 bar WG spring. :)

Any ever had excessive cutting out?

G.
-- 
"a thousand miles from here, there is another person smiling"
1990 Turbo (200t)
name   : gerard van vught
tel    : +27-57-912 2658 (w) / 082 923 9609 (cell)
url    : http://homepages.acenet.co.za/gerard/
e-mail : gerard@poboxes.com  / han.solo@galaxycorp.com
         gerard@acenet.co.za / van_vught@frg.issi.co.za