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What are these connections?

Posted: Sun Mar 03, 2013 12:50 pm
by josh2109
Hi folks,

I want to run a Pierburg and so I'm rebuilding one of my spares. However, the autochoke unit I've got is a bit different to the one on my Golf :? I've no idea what these connection are and what they should connect to, they're not present on the Golf. Are they vacuum lines?

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Re: What are these connections?

Posted: Sun Mar 03, 2013 2:19 pm
by ianaudia4
On VAGCAT it is showing as a thermo-pneumatic valve mate.

Re: What are these connections?

Posted: Sun Mar 03, 2013 3:50 pm
by josh2109
Cool - doesn't happen to show what I should I connect it to, does it? :D

Re: What are these connections?

Posted: Sun Mar 03, 2013 6:45 pm
by ianaudia4
No mate, it doesn't.

Re: What are these connections?

Posted: Sun Mar 03, 2013 7:11 pm
by josh2109
Bad times :( weird thing is I don't have any vacuum connections spare other than these. Guess I need to check the diagram on the slam panel, if it's survived. I'm guessing the rest of the carb should be set up the same as on my Golf?

Re: What are these connections?

Posted: Sun Mar 03, 2013 9:50 pm
by ianaudia4
You could go into your local VW dealer and ask them for a print of the ETKA page, it may give you a better idea as to where they fit.

Re: What are these connections?

Posted: Thu Apr 04, 2013 3:01 pm
by josh2109
A little bit of closure on this, I've also posted it up in my project diary.

As above, the part in question is a thermo-pneumatic valve, and it controls whether or not the the secondary stage of the throttle can activate. It's connected up via the green hoses in the below diagram:

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Below 28 degrees the valve is open, which means the secondary stage throttle can't activate as no vacuum can be held. Once the valve heats up above 28 degrees it closes, the secondary throttle stage system can now activate as vacuum can be held. Apparently this valve was only fitted to 1.6 litre manual and 1.8 litre automatic cars built after 1984, but I've fitted it to mine in the vague hope it may help solve the problem of my car cutting out when the engine is cold and the throttle is opened up.

Credit to Rubjonny's excellent Prierburg guide for the above information btw, as that's where I read up on this :)