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Thread: Acceleration Sputter, Hard Hot Start, Datalog Not Saved.

  1. #1

    Default Acceleration Sputter, Hard Hot Start, Datalog Not Saved.

    I've been working on my Sniper unit for a few weeks. I finally got it installed, starting & idling well with parameters within range according to the startup guide. Timing is 11° BTDC, IAC +/- 5%, Hot Idle bounces around 850 RPM +/- 30. I went for a test drive today and it seemed to be running well until the engine reached about 175°. After the engine got hot it started cutting out/sputtering/lurching under acceleration. If I kicked in into neutral it seemed to smooth out, but I would have to rev the engine much higher than normal and ease the clutch real slow to take off again. Even then it would cut out/sputter/lurch to get going again; it even died a couple of times. On restart, it would crank but it would not fire up right away like it did cold, and I would have to depress the gas pedal slightly to get it to fire. I let it sit and cool off, then repeated the process a couple more times. I started a datalog before my last drive, then stopped it after the drive before shutting the engine down. I popped the SD card into the computer to upload the datalog, but there is no file there. I know a datalog would be helpful, but apparently I can't even get that right.

    Any ideas on why I'm having this problem, and why my datalog was not saved?
    Well, I think I may have located my datalog, but every time I try to upload it here I get an "invalid file" error message.
    Last edited by 2B32; 04-13-2017 at 07:40 PM.

  2. #2


    In case anyone else has this issue, I called Holley and talked to a rep there. I gave him the rundown on my symptoms and he suggested I increase fuel enrichment from 49 lb/hr to 53 lb/hr. I drove around a while and haven't had any problems with acceleration or hot start since.

  3. #3
    Join Date
    Aug 2017
    Pittsburgh, PA


    Have/had very similar issues. Spit/sputter/backfire around 25-3000 RPM in any gear with operating temp at 180°F. I will give this a try, thanks for posting.

  4. #4


    Have same issue on my '65 Vette. Starts right up when cold, and runs great. But when restarting after warming to 180°F, it has the same issues you describe. Wants to die at a stop, and need to depress pedal slightly to get to start.

  5. #5
    Join Date
    Nov 2014
    Ont. Canada


    Quote Originally Posted by 2B32 View Post
    Well, I think I may have located my datalog, but every time I try to upload it here I get an "invalid file" error message.
    You can zip the file then post it here.

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