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Thread: Fuel Starvation Issues

  1. #11


    Thanks for the kind words, Chris.

  2. #12


    @unforgiven: You should be datalogging all of your runs and then reviewing the datalogs after each event. You can hook up a fuel pressure sensor and an oil pressure sensor by using the splitter cable from EFI Connection:
    Once you hook up those sensors you'll need to name the sensors and then add them to the datalog screens. You can setup warnings and alarms on the handheld or use your computer.

    Look at the upper right hand corner of your Base Fuel Table to see what the number is. That number will tell you what the base tune is planning to inject at WOT. You should also look at your Learn Table to see what adjustments it's been making.

  3. #13
    Join Date
    Dec 2009


    @unforgiven: (Holley Sniper EFI Help Manual - EFI Software, Tuning & Datalogging)

    Sniper EFI Software Help Information/Instructions:
    ‒ On the top Toolbar, click "Help" & "Contents". This opens all Help topics.
    ‒ When navigating the Sniper EFI software, click "Help ?" or the F1 key.
    ...This automatically opens the definitions for that specific parameter. (Holley Sniper EFI Software & Holley 558-443 CAN/USB Dongle) (Holley Sniper EFI Optional Comm/Data Cable Accessories) (Holley Sniper EFI SD Card Contents) (Holley Sniper EFI Help Manual - EFI Software, Tuning & Datalogging) (Holley Sniper EFI Instruction Manual) (Holley Sniper EFI Quick Start Manual) (Holley Sniper EFI Troubleshooting Guide) (Holley Sniper EFI Technical Information & Troubleshooting)

    EFI Software & ECU Firmware Versions:
    EFI SOFTWARE: Click "Help" tab (top toolbar) & "About Holley Sniper EFI".
    ECU FIRMWARE: Click "Sync With ECU" & "Get ECU Info" (Key-on/USB connected).
    The latest EFI software & ECU firmware can be downloaded here: (Holley EFI Technical Library) (How To Update ECU Firmware)
    Before updating firmware, ensure the current Global File is saved somewhere, since it will be erased from the ECU.
    The EFI (laptop/PC) software, ECU firmware & touchscreen unit must all be version compatible (LINK).
    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.

  4. #14


    Quote Originally Posted by unforgiven View Post
    I ended up melting the ring lands off the top of five pistons do to what looked like lean conditions.
    Are you sure it's not detonating? What do the plugs look like on the cylinders that didn't break?

    As luck would have it, I also found that the HyperSpark rotor had snapped its locating tab.
    I haven't seen nor heard of this until now. Would be nice to know the cause or is it a faulty part?

    BUT, the engine started acting like it was starving for fuel when under boost (10 psi). It'd darn near die, and I'd have to select neutral and feather the throttle to let it catch up.
    If you datalog it you will know for sure. The A-1000 pump should be enough for 600 HP even on E85.

    My conclusion is that the A-1000 fuel pump is not large enough, or it's failing.
    This pump is on the edge of an issue for 800 HP on E85. Once again, if you can watch the AFR during the potential issue along with fuel pressure you would not have to guess.

    Am I suppose to set my Holley external regulator which is on the return side, at 70 psi?
    There are reasons to increase fuel pressure, but they are usually related to needing more volume. Volume should not be an issue with the 8 injector model in your case even on E85, of course your pump would need to be up to the task also. I like to factor in at minimum a 10% margin for error when selecting a pump and injectors. Taking into account it would be nice to keep the injectors below 90% duty cycle, now you can factor in 20% margin of error.

  5. #15


    From experience with E85-98 and a 1800 pump. The 1400 would not even come close and the 1800 was at 70% at 6,500(we shift at 8,200) and 805 rear wheel. We had enough issues with "E" we changed fuels to save money on parts. I will say this was with a Dominator EFI 8x120 PPH injectors (at three bar) running 60 psi.
    Last edited by Twisted Z; 10-29-2020 at 12:52 AM.

  6. #16


    Sounds like you need a bigger blower. A 177 on a 383 pumping 10 psi is spinning pretty damn fast. However, I bet the torque curve is insane!

    If you're holding WOT for 20 minutes at a time, that intake is getting pretty hot. Especially with no intercooler or Water/Meth injection. It doesn't take much from that point to blow something up.

  7. #17


    Wow! Thanks for all the replies men.

    Thank you for the EFI software info Danny. I'll study up on it some more.

    A B C asked about the rotor fix. What I did was stone the edges on both sides of the plate where the rotor tab fits into. I just rounded off the sharp edges of the slot. I did not open the slot size, just smoothed the edges. I thought the plate might have been cutting into the plastic tab on the rotor and making it weak enough to snap. So far the newest rotor has not snapped the tab, and shows no sign of
    the plate cutting into it.

    Gen2Van: Hello. I have the 7" pulley on the bottom and a 2.8" on the top. YES, it spins fast. The belt starts to slip up around 4700 RPM. I plan on sending the pulleys out to be electric coated for more grip. The torque is impressive!

  8. #18


    That tune worked on the dyno, but I bet you didn't hold the engine at WOT for 20 minutes on the dyno. So you took a dyno tune and put it in a different condition in a race. You didn't hook up the sensors or take datalogs and you didn't set warnings or alarms on the key parameters. No surprise that you blew it up.

  9. #19


    @AndyF: I think you misread a post. The truck is running around for up to 20 minutes. It is NOT WOT for 20 minutes. It may see WOT for up to a minute at a time. I have an array of gauges that have warning lights on them mounted directly in front of me. Except for the fuel pressure, that one is in the engine bay. Also the handheld is setup for warnings also and is mounted on the front roll cage.

    Scold me if you will. But I have to start somewhere. I'm new to this EFI and tuning, NOT racing. Make no mistake, I do appreciate your input though. It helps to have another opinion to see something that may have been overlooked.

  10. #20
    Join Date
    Nov 2014
    Ont. Canada


    Hard to see from the pics, but it looks like most of the damage is in the ring land area. Being at WOT for a minute will create a lot more heat than a dyno pull will. Is your ring gap large enough to account for all the extra heat they will see?

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