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Thread: Confused

  1. #1

    Default Confused

    So I have been trying to get my engine to idle correctly. After finding a few issues, high fuel pressure, timing a few degrees off, TPS too low I've finally gotten it to idle to my liking. However now instead of it running super rich and popping in the exhaust, if I give it any throttle at all, the IAC goes up and it backfires through the throttle body. I know I've read here that it's suggested that backfires are not caused by the Sniper and most likely a mechanical issue, so I'll try and pursue any mechanical maladies. First off I will verify TDC again just to be sure, pretty sure my WBO2 sensor is not getting any errant oxygen caused by leaks, but I'll likely check that as well. I don't believe I have any vacuum leaks, but again I'll grab some carb cleaner and take a run through any possible leak points, any other suggestions? The engine is a Pontiac 535 with a Dual Sync Distributor controlling the timing (yes, I did sync the distributor at 15°). Also somewhere along the way the the fan outputs have stopped turning the fans on at the correct temperature, if I turn the key off and then back to accessory, the fans will go on as intended, but not at the initial turn on, figured that out the hard way when it started puking coolant. Including datalog from just the idle as that's all I can get it to do at this point.
    Attached Files Attached Files

  2. #2
    Join Date
    Dec 2009
    Location
    Connecticut
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    26,727

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    Quote Originally Posted by speedfreq View Post
    I know I've read here that it's suggested that backfires are not caused by the Sniper and most likely a mechanical issue...
    It's possible, but I wouldn't rely on that, especially if the engine didn't backfire before the Sniper EFI installation. Google "engine intake backfires".
    https://www.badasscars.com/index.cfm...&product_id=95 (Engine Backfiring Through Intake or Exhaust)
    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.

  3. #3

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    It's a new engine, it's only ever had the Sniper on it, so no other data.

  4. #4
    Join Date
    May 2019
    Location
    Ct
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    464

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    Have you double checked the Inductive Delay after you verified the Static Timing Set?

  5. #5
    Join Date
    Dec 2009
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    Connecticut
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    https://forums.holley.com/showthread...ing-Holley-EFI (Ignition Timing Synchronization - A Two Step Process)
    Troubleshooting & synchronization verification information at the end of post #1.
    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.

  6. #6

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    I'll read through that again. Any ideas on why the fan outputs may have suddenly stopped working?

  7. #7
    Join Date
    May 2019
    Location
    Ct
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    I'd double check all the connections and grounds to start.

  8. #8

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    @speedfreq: It's horribly lean. Transfer Learning To Base and add another 20% of fuel at the idle area. Then close your throttle blades until you get to below 10% on the IAC %. Read through the directions again and then we'll try to help with the fan issue.

  9. #9

    Default

    @speedfreq: Well you have a ton of problems so get ready to spend some time sorting them out. First off, you need to learn to pay attention to your handheld. Your engine is idling at 18:1 AFR with Learn maxed out at 50%. When you see the engine that lean you should shut it off. If your Base Fuel Table is so lean that you've hit the limit on the Learn Table then the Sniper will never run correctly. You have handcuffed the Sniper and it can't self-tune. The Config File you posted shows all zeros in the Learn Table so you probably forgot to download the current file from the Sniper. You need to look at the current file so you can see what is happening.

    Your Target AFR and Base Timing Tables are both Simple mode rather than 2D Table, which means you'll have problems. If you look at your Base Timing Table, you'll see a 10° step in timing from one cell to the next. That isn't a good idea.

    Do you have a laptop with the Holley SW installed? You're going to need one with that engine. Good luck, I had a dual Sniper setup on & off the dyno for a couple of months and never got it to work. I've heard of other people getting the dual Sniper setup to work, but my luck with them has all been bad.

  10. #10

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    I'm not running dual Snipers.

    I just looked at the Config File. Now I'm really confused. I know that's not the Config File I chose during Wizard setup and honestly until you mentioned it I didn't even really look at the file name when I sent it. That one is definitely a brain fart and may explain a lot. I just have no idea how I ended up with that Config File. OK so time to completely start over with a fresh Config File and go back over everything. And yes I feel like an idiot, but just bewildered by why that Config File was loaded. I did update the firmware a short time ago maybe something happened with that? Should I update again the firmware again just to be on the safe side? Maybe has something to do with the fans not functioning correctly?

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