Re: This thing that's clicking on my 200???

[Scott Mockry <scottmo@teleport.com>]

>Scott said:
>This is a new valve that was added on the dual knock sensor MC engine in
>the 1989 Model year. It does make a fair amount  of noise, and often is
>mistaken for a noisy hydraulic lifter. I would leave it connected, and not
>worry about the noise as this is normal.

>>Dave Lawson said:
>>It is also present on my 1989 single knock sensor MC engine. I have
>>never noticed the clicking, except when running the diagnostic output
>>tests.

Hmm.....The new valve mentioned above was only used with the dual knock
sensor MC-2 engine with the Mac14 ECU, and not  on the single Knock sensor
MC with the Mac11. The Mac14 MC-2 engine has TWO solenoids for the carbon
canister, one called the "frequency valve" on top of the intake boot, and
one solenoid called the "shut off valve" which is mounted behind/below the
intake boot as shown in this diagram.

http://www.sjmautotechnik.com/ecusys.html#carbon

Dave, does your MC-1 engine intake boot in the ur-q have the large
frequency valve, i.e. solenoid as shown in the above diagram? Possibly
there were some MC-1's which used the later intake boot and solenoid????

The 1989 200 with the dual knock MC-2 relocated the carbon canister to the
right side fender well BEHIND the tire and had the shut off solenoid
relocated behind the intake boot. 

The earlier single knock sensor MC-1 engine with the Mac11  ECU had the
carbon canister mounted in the fender well IN-FRONT of the tire with a
"frequency valve" or solenoid mounted on top of the carbon canister. This
MC-1 engine also used a vacuum controlled carbon canister "shut off" valve
mounted behind the intake boot.

The MC-2 engine basically switched to using a electrically operated
solenoid "shut off" valve instead of the vacuum operated shut off valve
found in the MC-1 engine.

Here is a diagram showing the MC-1 vacuum diagram and the carbon canister
vacuum connections.
http://www.sjmautotechnik.com/boost.html#hose

These changes and more are outlined in the Audi factory service training
book "1989 Model Change Information" WSP-521-180-00 and in the "1986 Model
Change Information" WSP-521-127-00

I currently own the 89 200TQ with the MC-2 engine which has this new
solenoid, and I have the earlier 5000TQ with the MC-1 engine which has the
single solenoid, I also owned an early 89 200TQ with the MC-1
engine.....and I thought it looked like the earlier 5000TQ MC-1 setup....

Gary E., what carbon canister setup does your early 89 200TQ have?

HTH
Scott gas-venting Mockry