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Thread: Air/Fuel Ratio Rising To 35% - Closed Loop Compensation 100%

  1. #11
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    18,634

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    Start by replacing the fuel filters & fuel pressure regulator (LINK). Also, check that the fuel cell foam hasn't clogged the fuel pickup tube/filter.
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  2. #12

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    UPDATE: I installed the in-line fuel pressure gauge. I have 60 PSI during prime, then it drops to 20 PSI when the engine starts, then drops to 1-5 PSI while the truck runs. The idle is rough and the truck dies under throttle. I clamped the return line to check the regulator and there is no change in pressure, which leads me to believe the issue is somewhere between the tank and the Sniper unit. I replaced the pump and still having the same problem. Next step is to check voltage to the pump and check filters. My fuel cell doesn't have foam, so the pickup should not be clogged, but I'll check it and the filters.

    Well, I finally found the problem. The gasket sealing the gas cap disintegrated and got sucked into the pickup, which would also explain why I never saw any debris when I looked in the tank.

    Click image for larger version. 

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    Last edited by 2B32; 05-15-2017 at 08:18 AM.

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