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Thread: Off Idle Hesitation

  1. #1
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    Default Off Idle Hesitation

    Ford 347 stroker. I had noticed a slight off idle hesitation when I would stab at the gas real quick and rev the engine, but nothing awful. I had it in the shop the other day, and he commented on how it ran like crap. It died when he quickly hit the gas to rev the engine, and then it started hard. I didn't believe him because it had never done that for me. Hard starts sometimes, but had never died. Well, today it happened three times after letting it get to operating temp. What do I need to look at on the laptop to fix this?
    Last edited by 66FSTBK; 12-19-2014 at 09:30 PM.

  2. #2
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    Quote Originally Posted by 66FSTBK View Post
    I had noticed a slight off idle hesitation when I would stab at the gas real quick and rev the engine, but nothing awful.
    A "slight off idle hesitation" doesn't happen when quickly stabbing the throttle and revving the engine.

    If it hesitates/bogs when stabbing the throttle, look at your Acceleration Enrichment tables.
    Of course, the Base Fuel Table must be well tuned, because AE can't cover a lean Fuel Table.

    Conversely, if you have a momentary lean spike, on light throttle acceleration,
    check your AE vs TPS/MAP RoC Blanking values (in Fuel Modifiers/Fuel Control):
    If they're 15 & 7, those are the old values from the V1 firmware.
    Change the AE vs TPS RoC Blanking value to 4-6.
    Change the AE vs MAP RoC Blanking value to 5-7.
    Some users reported the need for an even lower TPS RoC Blanking value.

    http://forums.holley.com/showthread....4929#post54929 (Additional Information)
    http://forums.holley.com/showthread....8078#post48078 (Additional Information)

    Hard starts sometimes, but had never died.
    http://forums.holley.com/showthread....8385#post48385 (Prior Starting Issue)
    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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    I just changed the Blanking values.

    My old thread you linked to, ended up being a failed WBO2 sensor.

    I had to increase my Acceleration Enrichment due to detonation/pre-ignition issues under load (being in 3rd or 4th gear and trying to
    accelerate when cruising under 1700 rpm). Fixed that problem. I don't want to pull too much out in fear that this problem will come back.

    I also merged the Learn Table with the Base Fuel Table, and smoothed it out. Going to test it out this morning.

  4. #4
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    Quote Originally Posted by 66FSTBK View Post
    I also merged the Learn Table with the Base Fuel Table, and smoothed it out. Going to test it out this morning.
    From my experience, this is a very common fueling issue.
    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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    I adjusted the Acceleration Enrichment downward and the blip went away.
    I noticed it was doing it when the TPS was below 30%. I also dabbled with a few other things today.

    I noticed this after I revved the engine. Are the rich & lean spikes a big deal? Could they be false readings?
    These registered on the software AFR gauge when I was online with the ECU: http://youtu.be/UCg1P-cPWjM

  6. #6
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    Quote Originally Posted by 66FSTBK View Post
    I noticed this after I revved the engine. Are the rich & lean spikes a big deal? Could they be false readings?
    These registered on the software AFR gauge when I was online with the ECU: http://youtu.be/UCg1P-cPWjM
    No, that's not right. It's extremely rich when you rev the engine.
    This is either too much AE, or a lack of Fuel Table tuning at WOT.
    Datalog & tune. You may need to seek the help of a professional tuner.
    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.

  7. #7
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    Quote Originally Posted by Danny Cabral View Post
    No, that's not right. It's extremely rich when you rev the engine.
    This is either too much AE, or a lack of Fuel Table tuning at WOT.
    Datalog & tune. You may need to seek the help of a professional tuner.
    I'll try to adjust the AE. Is the ECU over compensating when this rich condition occurs, causing it to go lean afterwards?
    I found someone here locally that has experience with Holley EFI tuning, and he wanted $550 to tune.

  8. #8
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    Quote Originally Posted by 66FSTBK View Post
    Is the ECU over compensating when this rich condition occurs, causing it to go lean afterwards?
    I don't want to speculate, without a Datalog & Global Folder. However, since you've had this EFI system for over a year, and the fueling still isn't right, I concur with hiring a professional tuner.
    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
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    Quote Originally Posted by Danny Cabral View Post
    I don't want to speculate, without a Datalog & Global Folder. However, since you've had this EFI system for over a year, and the fueling still isn't right, I concur with hiring a professional tuner.
    I will post a datalog this afternoon. If I begin to make changes to the AE or Fuel Table in general, won't the Learn function of the system begin to modify my changes if I don't turn the Learned Compensation Limits % down?

  10. #10
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    If you plan on doing some manual Base Fuel Table tuning, "Transfer Learning To Base", smooth the Fuel Graph and disable Learn.
    In the EFI software, open the "Help" Contents (top Toolbar), and read "Base Fuel Table Tuning Quick Guide" for more information.
    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.

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