Re: 89 200TQ Decel valve operation - the conclusion. Attn: an error in the Bentley!

[e6941tb@ix.netcom.com]

A sincere bow of appreciation goes to Scott Mockry.

scott.john.mockry@bangate1.TEK.COM wrote:
> 
> Igor,
> 
> I thought of a couple of other things to check out after you verify the wiring,
> temp sensor, idle switch is ok. I did a repair on another list members idle
> control unit (I think it was for an 87 5000TQ, yours may be different).
> I assume being the curious guy you are that you will take a look
> inside your idle control unit if the problem still exists,

Bingo! That was the Control Unit.
 
BTW, Bently (both the 3 vol '89-91 and the 2 vol '84-88) erroneously
shows the Deceleration Control Unit in the pos. 3 on the underhood
fuse/relay panel. That is a BS! It is a rad. fan stage 2 relay. The DCU
is located in the aux. underdash relay block on a 5000 and behind the
driver side kick panel on a 200. It looks like a giant dual relay. Not!
There are 2 denceley populated, conformal coated PC boards inside that
unit.

I checked everything (the valve supply voltage, the Idle Switch, the
temp sensor), including the wiring to the Control Unit. The only option
left was the Control Unit itself.

I did it the easiest way possible (yes, I cheated, I admit). I drove to
NJ to a good friend of mine, Michael Zamikhovsky (who has recently
joined the list), coz 3 out of his 5 Audis have an MC turbo engine in
them. So we just temporarily swapped the CU's and the valve has started
working.

>  On this other list
> members unit, I found one of the large resistors that
> was used to limit current through the idle stabilizer valve was cooked and
> had ~200K ohm resistance when it should have had something like 0.33 ohms.
> 
> Even though this cooked resistor is NOT what may be causing your problem
>  you may want to poke around inside your idle control unit and look for
> any other cooked components or bad solder joints.

The only huge ballast resistor that I found there was the one with
56ohms nominal and it checks fine).
Tomorrow I'll start testing the board.

Does anyone know wou much do they go for?

BTW, since no one reply to my post, I am asking this dumb question over
again: what are the Mann and the Mahle P/N for a turbo car? Wanna buy a
case.

Igor Kessel
'89 200TQ

P.S. If it were not for my self made, multicoloured LED'd OXS monitor, I
would have never guessed that I had a problem. Would have being happily
feeding gasoline to my Q in both the uphill driving and the downhill
engine braking, wondering why the gas consumption was on  par with a
truch.
They are available from at least 2 vendors (Hal Meter and Cyberdine) and
are very_usefull.

Igor Kessel
'89 200TQ