Thread: CIS fuel head
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Alan L Alan L is offline
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Join Date: Apr 2006
Location: New Zealand
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CIS fuel head

Folks , since we probably prefer not to go there, I am posting a pic of the inside of a 930 fuel head. Since I've pulled it apart.
It is not too different to the 911 head (CIS fuel distributer cleanout w/pics)
But I am none the wiser at the moment as to why the air plate is vibrating so bad at idle. I have raised the metering piston (the bit that sits on the air plate arm) just so you can see it. Supposedly there is supposed to be a small orifice in the head of this piston area to dampen the movement. But I can't find anything like that - other than a couple of decent holes in the head of the body leading into the top of the piston - which in fact I suspect connect to the WUR. There is a bit of scoring on the piston where it has been chattering in the metering chamber. There is also a light spring which sits on top - presumably to assist damping, or the balance on the plate arm.
I have partly assembled the springs/diaphragm so you can see how it goes together. On the top of the head, by each injector connection, you will find some small allen head screws. These seem to screw thru to the inside and set the spring tension - I'm guessing this is how you set all the springs up even.Well the mystery continues. I'm just hoping someone in CIS- land can point me to the cause of my problem, because it has got me stumped. But it really is too serious to try and operate the car like this.
Old 11-29-2007, 05:57 PM
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