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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progress report

Thanks Nathan. I tried some lower pressures - dropping one spring out, winding the adjuster back. But it seems it wants to run at 50 psi. I had it running at 40 psi, but it is loading up with too much fuel at the moment. Too rich. Not sure what is causing this. Seems to be on the factory setting then - for a 3.6 T.
BUT, good news. No Fuel head leaks and NO PLATE FLUTTER.
I am very happy about that. It seems the scored piston was at fault. You have no idea how good a rock steady air plate looks to me right now. Having been thru all that, I have concluded in hindsight that I could have replaced the piston without splitting the fuel head. It pings out the bottom once you let the lock tab go. But I had no idea what I was looking for, and it could have been a damaged diaphragm or whatever.
I just have to get this mixture leaner now. Not sure how many turns I have on the adjuster screw before it falls out into the airbox. Scares me.
My piston is about 0.5 thou smaller in diameter than the original - but minus the scoring. Not sure if this difference is letting more fuel thru or not. Seems worse at idle, with a few revs seems happier.
Will have to investigate further. Spent ages synchronising the injectors. Very tedious.
Thanks for the help guys, and Goran, you can relax now.
Seems Bosch and I came to the same source of steel for the pistons - the coeff of expansion was the same, and mine came out 0.7 gm heavier by the time I finished it in the original shape. I intentionally left extra on originally - better too heavy than light - can always take some off.
Old 12-04-2007, 07:53 PM
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