latest on boost saga

robert weinberg centaurus3200 at
Wed Dec 17 21:37:42 PST 2008

yeah, let's just hope she's good to go for the foreseeable future.

one reason to finally sort this out is i've been driving my 98 nissan sentra in the rain here in the bay area. no abs, rear drums, headlights even worse than the 200, no quattro (obviuously) and the most annoying thing ever. there's like no insulation in the car, so everything fogs up in cold weather - even the defrost with the a/c on barely cures it. it's a wind-up toy ;-)

good to have the 200 back for winter. california winter, but close enough for me ;-)

see ya,

--- On Wed, 12/17/08, Mike Miller <mikemilr at> wrote:
From: Mike Miller <mikemilr at>
Subject: Re: latest on boost saga
To: centaurus3200 at, "200 20v List" <200q20v at>
Date: Wednesday, December 17, 2008, 7:59 PM

Thanks, Robby - glad it seems the problem is solved. Guess I am not sure just
which hose is the ECU MAP hose.

Put on some snow tires and come to MT and we can try it out. Believe me, boost
is *awesome" at 10- 20 deg below air temps but one does have to watch out
for the ice <g>


----- Original Message ----- From: robert weinberg
To: 200q20v at
Sent: Wednesday, December 17, 2008 8:41 PM
Subject: Re: latest on boost saga

awesome post Mike!

well, i got the call from dan at 034 at 5pm. according to them, they have
finally solved the issue. they said nearly every ground wire and terminal was
corroded. they said the ecu MAP hose was leaky too.

i decided to give ian back his ia3+ ecu and go for the $250 discount on the 034
stage I (280 HP) and 3 bar notched MAP sensor.

they said the car lit up the street repeatedly and without fail. and, according
to their tech Nate, it's hella fast (SF bay area ;-)

so, pulling the turbo was an expensive endevor (even at their buddy deal
$55/hr), but at least i know every inch of the car has been gone over by javad
and crew.

gonna pick it up tomorrow. and being it's an old T44 audi, i fully expect
the problem to recurr on the way home ;-)

see ya,

--- On Wed, 12/17/08, Mike Miller <mikemilr at> wrote:
From: Mike Miller <mikemilr at>
Subject: Re: latest on boost saga
To: centaurus3200 at, 200q20v at
Date: Wednesday, December 17, 2008, 7:21 PM

Hi Robby,

I'll take a stab at it here as I have BTDT with low
boost when I bought my 1st 200q in 1996. I had a normal reading on the WGFV but
it was bad - Ned Ritchie of IA and I spent many hours troubleshooting
it and I think mine was the 3rd one found to be bad in the US. Took over a
to get the part from the father land.

If you pinch of that hose from the WGFV to the WG,
you will remove ALL ECU control of the WG. Have you done that yet?

You say you have a new Bypass valve correctly
installed. Have you verified the hose the entire length from the back of the
Intake Manifold to the Bypass valve? If anything is bad ( like it is crimped at
the bracket on the back of the IM) the Bypass valve will dump boost

Good to hear you have the Samco's - that should
eliminate any leaks there - which would show up on a pressure test anyways.

I don't recall what you are seeing for low boost
when you do experience it. Is it possible the car is in limp home mode (
bar) due to a bad MAF sensor? Try to borrow one if possible as they are quite

There is a high altitude sensor - when I turn on my
key at 5000 ft elev. the boost gauge reads .9 or .8 bar. With stock ECU I would
never see over 1.7 bar and yet I would get 1.8 bar under about 3000 ft
elev. At 10k+ ft elev boost was limited to 1.6 bar as I recall. The purpose
is to prevent over spinning the turbo in the thinner high alt. air. I guess
figured 100k rpm was enough :-)

Basically, the WGFV is the way the ECU controls
boost - it pulses the WG and prevents it opening at lower boost and then it
allows it to open as you approach the max boost your ECU allows. If you exceed
max boost ( like with the hose pinched off or a stiffer WG spring) the ECU
will ground the fuel pump and not allow you to exceed 1.3-1.4 bar until the
ignition is cycled.

Your problem (to me) sounds like an issue with
either the hose to the bypass valve or a flaky MAF sensor. If you are running a
K&N air filter, some people have experienced the oil from the filter
and ruining the MAF sensor - I have never had the problem personally. I am
assuming you have checked the air filter - I did have a rodent build a nest in
my F350 airbox a few yrs ago the severly limited boost. Little SOB chewed out
the bottom of the filter and used it and sone underhood insulation for nesting
material. Went from 24 lbs boost to 14 lbs.

You may not know that you can driil out the top of
the WG in the center and tighten down the screw inside to increase spring
pressure - allows for faster spool up of the turbo - same as putting in a
stiffer WG spring only "free".

I think I saw where you said you had checked
*every* fuse in the fuse box. I think there are a couple there that will limit
boost - like that double one nearest the fender in the middle with
"moteur" or
something like that labeled on it.

Just out of curiosity, what are you seeing for fuel
economy? I'm running an MTM chip ( have run stock and Hoppen stage 1) and I
21-22 around town and 25-28 hwy. The reason I ask is that a clogged Cat-con can
cause low mileage and low boost. A loose part in the exhaust will occasionally
allow normal performance. Just one more thing to look at :-)

hope some of that is useful


----- Original Message ----- From: robert
To: 200q20v at
Sent: Wednesday, December 17, 2008 5:53 PM
Subject: Re: latest on boost saga

hi mike,

it's an 034 billet bypass. it was installed

i wish i knew what the stock ecu did but i bought the car with
a dead autocheck. boost, trip, etc. i chipped the car while it was still

i developed the boost issues. somewhere in between, i got around to
frankensteining a another dash's electronics (that white flip down back
onto my dash which fixed the autcheck, et al.

i'm also running samco
hoses - any leaky boost and vaccuum lines were just replaced by

there's definitely something screwy going on with the computer and
the wgfv. it's reading 1.4 bar like it's not even connected - but it
is. 034
tried a known working valve. no change. they measured the correct signal from
the computer to the connector.

but something is getting mixed up. and
sometimes, it works and the car is a flippen rocket.

help me learn, what
is the purpose of the whole WGFV system? to allow the computer to lower boost
high altitude?

from my understanding, that's the only time the computer
lowers boost. it does not lower boost during detonation, correct? only pulls


--- On Wed, 12/17/08, Mike Miller <mikemilr at>
From: Mike Miller <mikemilr at>
Re: latest on boost saga
To: 200q20v at
Date: Wednesday,
December 17, 2008, 4:39 PM

I forget - has the turbo bypass valve been
replaced and is it hooked up
correctly? It is easy to hook up backwards which
I believe can limit boost. What
kind of boost does a stock ECU make when


----- Original Message ----- From: Chris
To: 200q20v at

Sent: Wednesday, December 17, 2008 5:15 PM
Subject: Re: latest on boost

I'd hook up a test light (LED) to the wastegate frequency valve
That way you can watch what the computer is telling the WGFV to
do. If I
recall correctly, the LED should light up solid then flash
rapidly as boost
builds. If the light stops flashing or goes off, that
means the signal from
the computer is not closing the WGFV and you'll have
the 1.4 bar boost max.
Make the lead to the LED long enough and you can stick
the LED under the
windshield wiper and watch it while driving (or run it in
the window to the

Check the basics, too; grounds; wiring
condition at the multifunction temp
sensor; condition of the gear on the end
of the distributor.


On Wed, Dec 17, 2008 at
10:42 AM, robert weinberg
<centaurus3200 at>

says they GAURANTEE they've checked every flippen sensor or possibility
the car. at least she did boost for a little bit with my computer. Dan
at 034
said he can believe the ecu going bad - like the pressure transducer
- but
what would make for a flakey chip? they are open to

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