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Alan L Alan L is offline
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Join Date: Apr 2006
Location: New Zealand
Posts: 3,261
Nathan, this all makes good sense - and you gave me an idea. I have now found I can replicate the problem with the car not actually driving - but simply going thru the throttle movements that would cause the problem on the road. So I spent some time last night watching my CIS gauge on the WUR as I induced the lean AFR by raising revs beyond idle.
The pressures barely moved - altho did increase by about 3 psi at higher revs. I suspect this may be a voltage issue for the fuel pumps - at a guess. My battery is near the end, so this is about the only explanation I can think for that behaviour. But the leaness cuts in prior to this while the WUR pressure is rock solid. Every now and then it would clear itself and the AFR would drop down. This suggests the fuel head/piston - as Goran suggested.
I pulled the head again and played with both pistons in the bore. Every now and then both of them would catch slightly and temporarily. Go back to the same spot of rotation and travel next time, and smooth as. Given the minute clearances in the bore - about a thou, I am wondering about grit in the fuel system.
I am about to pull the fuel tank, and have ordered a new filter.
We will see.
Old 07-29-2008, 12:38 PM
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