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RarlyL8 RarlyL8 is offline
Crotchety Old Bastard
 
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Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,255
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Something is wrong with the fuel delivery, but you know that. How is your system pressure? Is it stable at 100psi? With only descriptions to go on it sounds like you have a weak fuel pump. That would explain the erratic and inconsistent readings. Would also explain why your WCP raises when you depress the air meter plate. If your flow is 60% of what it needs to be you will never be able to tune the system.
As for the fuel distributor tuning, it is rather hard for me to write it in terms that are easy to interpret but I will try. The fuel distributor can only operate at 100% capacity. Simplistically if you shut the flow off to 5 of the ports then #6 gets 100%. If you open another port then those 2 ports share 100%. How much they share depends on how far open they are to both total flow and as compared to each other, because opening the 2nd port takes away flow from the 1st port. Open 3 and you have to re-balance all 3, open 4 rebalance all 4, etc etc until all 6 are open and balanced. It's a 6 way see-saw that is extremely tedious when close to 100% capacity. You can only imagine what a flaky fuel pump would do to that effort. When you are close to max volume it becomes more difficult to determine the point where 100% overpowers the adjusters as a whole, meaning all 6. This is where the fuel pressure regulator adjustment comes into play. If you already know this please disregard, I'm not trying to talk down to you. If you didn't know all that I'm sure you suspected it.
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 11-01-2017, 07:00 PM
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