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Thread: Sniper EFI flooding?

  1. #1

    Default Sniper EFI flooding?

    So the other day I did a burnout and launched, then the Nova started running really bad. At first, I thought I broke something in valvetrain, but all rockers & pushrods looked good this morning. Now I’m wondering if the Sniper is just flooding the engine (383 stroker). It fired right up this morning the started running rough again. I pulled air cleaner off no fuel dripping with just key on, but with it running all 4 injectors are pumping fuel. I’ve never looked down Sniper with it running before. Are all four supposed to be squirting fuel?

  2. #2


    Look at the gauges on your handheld. What do they say? What is the AFR? Does Fuel Flow look normal? What's your fuel pressure? Do you know how to use the datalogger?

  3. #3


    Idle AFR is around 11, then it’ll drop to 9 while driving. I’m thinking another bad WBO2 sensor. Yes, I know how to datalog, just no time to do it right now.

  4. #4


    Where are you reading the AFR from? The Sniper or a separate WBO2 sensor?

  5. #5


    Sniper handheld display.

  6. #6


    What I wonder is what are the symptoms of a bad WBO2 sensor and reading on the handheld or Sniper EFI software? Would they just read fat or lean or be frozen? If you had a separate WBO2 sensor to compare it to. I actually have two. One on each header, but of course the Sniper only sees one.

  7. #7


    To answer one of your original questions, yes, all four injectors operate at idle unless you've installed the Progressive Linkage and checked the progressive linkage box in the Sniper EFI software.
    69 Camaro
    400 SBC, ProCharger D1SC

  8. #8
    Join Date
    Dec 2009


    Originally Posted by Danny Cabral
    Is the Sniper EFI Learning? Is the ignition timing synchronized? Is the fuel pressure 58-60 psi (LINK)? IAC Position
    of about 5% at hot idle? Check for ignition misfires/RPM signal problems, exhaust leak upstream of WBO2 sensor,
    or if the WBO2 sensor (or other sensor) has failed and corrupted the Learn Table. Look at the Data Monitor/Gauges.
    Also, the Holley Sniper EFI will intermittently inhibit Closed Loop at idle, if the AE vs TPS/MAP RoC Blanking values are set too low. (Holley Sniper EFI Help Manual) (Holley Sniper EFI Troubleshooting Guide) (Holley Sniper EFI Fuel Pressure Tester/Gauge)
    Originally Posted by Danny Cabral
    The Target Air/Fuel Ratio Table & Base Fuel/Timing Table (and MAP kPa & RPM axes/scales) should be configured using the Sniper EFI software:
    In the Sniper EFI software (LINK), Target Air/Fuel Ratio Table (Fuel ICF) & Base Timing Table (Spark ICF), select "2D Table" Type (not "Simple").
    The Target Air/Fuel Ratio Table & Base Timing Table can then be properly configured & tuned for any engine. (Sniper EFI Software & Holley 558-443 CAN/USB Dongle) (Sniper EFI Optional Comm/Data Cable Accessories)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 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, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 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 tires.

  9. #9


    Quote Originally Posted by gregs69rs View Post
    To answer one of your original questions, yes, all four injectors operate at idle unless you've installed the Progressive Linkage and checked the progressive linkage box in the Sniper EFI software.
    Should they be misting fuel or fuel coming out pretty heavy?

  10. #10


    I believe it's a mist, but I have never looked at mine personally. Do a YouTube search, as I believe there are videos showing stuck injectors.
    69 Camaro
    400 SBC, ProCharger D1SC

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