# CIS Expert Questions



## ShawnO (May 29, 2002)

I have 2 idle control plungers for my CIS-E fuel distributor 0438101005 

Any idea which one is the correct length?

55.82 mm
53.31 mm


The other problem I have is when I try to roughly set the idle mixture screw per the Bentley at 19.0 MM. The lowest I can get 18.41 MM and the screw bottoms out. The part number is 026133353a.

The vehicle in question is a 1987 Scirocco 16V 1.8L.

It sort of leads me to believe I should use the longer shaft but I'd like to set the dizzy in spec since it's already gonna be a chore to make sure everything else is working right as it sits now.

Any help is very appreciated.


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## WaterWheels (Aug 14, 2005)

First the part numbers, they are both correct for the car/engine. Now the real fuzzy part, _"I have 2 idle control plungers for my CIS-E fuel distributor" _. First is are you talking about the control plunger? There is no idle control anything on the fuel distributor. Second is that you say you have two (2). The plunger is machined to fit the fuel distributor *EXACTLY* and can not be swapped with any other. They are ground to to match with a very small clearance, something like 0.0005", and although it might fit and work into another fuel distributor, you are advised to replace the fuel distributor if any damage is done to either.

Bentley states about 19mm but Bosch states about 21mm, I found Bosch to be closer. That is only a starting point to get things to run and will change as the engine is tuned correctly. What about the sensor stop, is that effecting things? You do know you can't just place it on a table and do this as the arm of the sensor plate is pushed up a little then, right?


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## ShawnO (May 29, 2002)

Well what happened is I ordered a rebuilt fuel dizzy and the plunger that came with the rebuilt was longer than the one in my core. Same part numbers on the dizzy though. I'm gonna go with the shorter one from the old and see what happens. It fits so we'll see..... I'll update if I get the thing trying to fire this weekend. Still gotta put the head on but all my parts are in. Depends on how much my wife helps with the kids.

I did check the stop and spaced it out further but the thing is bottomed out. The funny is I have a running working Scirocco that I've already done this with before and had no trouble. If I have too I'll take the one off my running car and compare the 2.

I think the deal with the 19mm is I was measuring from where the dizzy gasket sits on near the center. I placed a straight edge on the raised portion of the base that the dizzy rests on and took out for the straight edge and was able to set it at the 19mm however it's almost bottommed out so who knows. 

I guess the worst thing that can happen is it doesn't fire and I swap out the plunger and get it working then. 

I will check on measuring at the bench but it did not feel like the bench was pushing up on the lever. Point well noted though.

I'll also update what the correct length for the plunger is.

Waterwheels thanks for helping tackle this. You advice is appreciated.:thumbup::thumbup:


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## dkfackler (Feb 8, 2010)

We used to set the initial plate setting by putting a nickel on the mixture control plate and turning the screw until the narrowest point in the air cone just cleared the top of the nickel.

That got it running, then the adjustment was fine tuned using a ColorTune(http://www.international-auto.com/index.cfm/fa/p/pid/3448/sc/27175)(says 'carburetor', but works fine in injected engines too) in the Nr 1 plug hole.

When the ColorTune showed a nice 'stove gas blue' at idle, we called it done, regardless of plunger height.

Just a thought, but it might help.


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## ShawnO (May 29, 2002)

Thanks for the advice.

As I got further into installing everything this weeked I figured out I was missing some more parts. Being in Alabam I'll have to wait until next weekend before everything arrives but no updates yet.


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