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Thread: 12-700 Billet Pump Gets Noisy

  1. #1

    Default 12-700 Billet Pump Gets Noisy

    Before my problem, here is the setup: I have a Terminator EFI setup on my '68 Impala SS427. I used a 12-700 fuel pump, and Holley pressure regulator set to 43 psi (no vacuum). I just changed my tank setup to have 3/8" lines in and out. I'm using a 33033 20 micron pre-filter with a 10 micron post filter. The pump is located lower than the bottom of the tank, but the lines do arch over the rear dog leg which is higher than the tank. The tank is vented properly. The EFI computer is powering the pump on the green wire.

    When I first start the car, the pump is really quiet. After a bit of spirited driving to get temps up, I notice that the pump starts to get noisy. This is in a convertible. Once I park it, the pump is much louder, and it is warm to the touch. Not crazy hot, but you wouldn't want to hold it forever. Anyone got any ideas? I added a 3/8" return to my tank and have it dumping below the fluid level, so I doubt it is foaming up.

    Outside of the noise, this thing is driving better and better. The throttle response is really improving!
    Last edited by howpeculiar; 07-11-2014 at 09:39 PM.

  2. #2
    Join Date
    Dec 2009


    Quote Originally Posted by howpeculiar View Post
    I'm using a 33033 20 micron pre-filter...
    This is the problem; wrong filter. 20 micron is way too fine for a pre-filter! Replace it with a 100 micron filter. (Fuel System Selection Chart) (Holley Fuel Systems Brochure) (Read 2nd quote box.)

    ...with a 10 micron post filter.
    10 micron is correct for the post-filter.

    Only need two EFI fuel filters:
    Before fuel pump - 100 micron pre-filter. (Or the OEM in-tank sock filter.)
    After fuel pump - 10 micron post-filter. (40 micron is for carburetion.)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

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