Cold start valve for a CSi

Drew20

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Is the issue you're seeing the cold start valve or the aux air valve?
I think of the cold start valve as the 7th fuel injector, which dumps extra fuel into the manifold on a cold start
The aux air valve (aka the slide valve) is the extra air intake, controlled by the wax bulb stat.

Your issue sound like aux air valve, which often causes issues as you describe, i.e. the extra air intake can either jam wide open, or not fully close when engine is up to running temp
Can be rebuilt. I've done a temporary fix on my car by carefully squeezing the wax stat bulb in a vice, just a wee bit, to move the "closed" position on the AAV. I suspect if your AAV is jammed open then this temporary fix is not going to help.
 

merdad

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I also used to take the hose that goes to the manifold off at the auxiliary valve when the car was warmed up, and block the opening with a large cap.
I also did remove the auxiliary valve and boiled it in pan to free up the movement and or see if it closes fully at hot temperature.
 

Simufly

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It sounds to me like a stuck AAV. Asimple check with a warm engine is to put you hand over the intake on the filter/silencer for the AAV. If there is suction and the revs drop its the AAV. You can then either block off the input on the plenum or replace the AAV!
 

sfdon

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I just shipped units to Carl Nelson at La Jolla Independent
He may a few left.
 

pmansson

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Thanks to all. Yes, it is the AAV. I just removed the filter and put my finger tip against the tube , and the revs dropped to normal (with hot engine?
how important is the filter? How about replacing it with a wine cork?
 

Simufly

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Thanks to all. Yes, it is the AAV. I just removed the filter and put my finger tip against the tube , and the revs dropped to normal (with hot engine?
how important is the filter? How about replacing it with a wine cork?
As the name suggests its a cold start valve so when the engine is warm it is not is use. without the filter there is a direct path for any debris to go straight into the cylinders. If you can do without the cold start then just block off the inlet on the plenum until you get the system refurbished or replaced.
 

sfdon

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Available on Swiss ebay....



And dealer


And Carl
Carl Nelson La Jolla independent

And Pelican


And me

Or you can re-build your own. I don’t recommend it.....


In Norway: kit with instructions

 
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