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Thread: 383 bogs down off the line at WOT.

  1. #1

    Default 383 bogs down off the line at WOT.

    383 SBC with aggressive cam, aluminum heads. I have the system dialed in pretty well, but if I'm stopped and just stomp it to WOT, the engine just bogs down and the AFR goes very lean, 20:1 area. If I step on the brake and add power slowly, then go WOT, it does great. If it were a carb I would go to a bigger carb cam & squirter. Not sure how to do the equivalent on the EFI.

    Timing: Idle 22°, cruise 40°, WOT 34°
    AFR: Idle 14.3, cruise 13.8, WOT 13.0
    Idle set to 850. Thanks for any help! Rob

  2. #2
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    Quote Originally Posted by nutsf15c View Post
    If it were a carb I would go to a bigger carb cam & squirter. Not sure how to do the equivalent on the EFI.
    Acceleration Enrichment parameters, especially the AE vs TPS Rate of Change.
    http://forums.holley.com/showthread....9444#post29444 (EFI Acceleration Enrichment In Carburetion Terms)
    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.

  3. #3

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    If it was a carb, you would think you had either too little a pump shot, or wrongly timed shot. It would take a while to narrow down what cam, squirter and even sometimes the volume of the accelerator pump. But on the EFI, it's pretty easy. You can change the Accelerator Enrichment on the computer and easily keep tweaking until you are happy without buying any parts!

  4. #4
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    Although the Terminator Acceleration Enrichment parameters are usually rich enough, so first ensure it's not a Base Fuel Table issue. Also, ensure the AE vs TPS Blanking RoC value isn't too high (Fuel ICF/Fuel Modifiers/Fuel Control).
    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.

  5. #5

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    On my Dart 427, I ended up with Acceleration Enrichment at 70 for zero off the line issues. I'd work enrichment up in increments of 5 until you notice it's basically spot on, then come back down in increments of one until bog just comes back, and go back up 1 and be done. Timing has to be set where you want with no more adjustment.

  6. #6

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    OK guys, I've looked at a lot of these settings. AE was around 2, it's up around 10 now, and runs better. If I go much above that it starts running poorly with just cruising. Plus, the computer won't let me go past 31? I've tried adjusting the AE vs TPS, but nothing I have tried has helped the stalling with full pedal off the line. Any other ideas?

  7. #7
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    Quote Originally Posted by nutsf15c View Post
    ...but nothing I have tried has helped the stalling with full pedal off the line. Any other ideas?
    We need to know why it's stalling at WOT. Too lean, too rich, timing synchronized? Record & review a short datalog of this occurrence; it should reveal the problem.
    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.

  8. #8

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    "...but if I'm stopped and just stomp it to WOT, the engine just bogs down and the AFR goes very lean, 20:1 area."
    Been doing all the adjustments on the 3.5" LCD touchscreen, not savvy on the computer datalogging. Probably wouldn't know what I was looking at, if I could figure it out.

  9. #9
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    The 3.5" LCD Touchscreen has a Data Monitor & Gauge screens. AFR is one of them.
    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.

  10. #10

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    Yup, that's correct. So, why does it go lean when I hit the throttle?

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