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Thread: Tuning Help

  1. #1

    Default Tuning Help

    I got to drive my car for the first time, since installing the Dominator using a Terminator throttle body. I really only have one problem I cannot figure out. I have a stumble after the transmission shifts (4L60E). If I nail this thing from a dead stop, no hesitation and runs great. If I'm putzing around town with a really light throttle, after 1-2 & 2-3 shift, it doesn't seem to recover well. The RPM drops from the shift, and if I keep the throttle steady, and it just goes dead for a split second. I'm lost...I tried different Acceleration Enrichment adjustments, but no help. Tom

  2. #2
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,676

    Default

    Quote Originally Posted by FuelieNova View Post
    I have a stumble after the transmission shifts (4L60E).
    The RPM drops from the shift, and if I keep the throttle steady, and it just goes dead for a split second.
    Look at where this happens on the Fuel Table. Does it go lean or rich?
    Record a datalog, activate the overlay feature, and play it back on the Fuel & Timing Tables.

    It may still be too lean and may require more timing advance (not WOT).
    Read pages 4-10 of this Edelbrock EFI tuning manual, it's very good:
    https://edelbrock-files-v1.s3.amazon...ers-manual.pdf

    I'm lost...I tried different acceleration enrichment adjustments, but no help.
    But you're not actually accelerating with the throttle?

    Check the Target A/F Ratio Table too; it may be commanding an
    AFR that's too lean (meaning it's not the Base Fuel Table's fault).

    What are your AE vs TPS/MAP RoC Blanking values (in Fuel Modifiers/Fuel Control)?
    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 ECU 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.
    Ensure there's no TPS/MAP RoC signal activity at idle, due to noise/kPa fluctuation.
    Acceleration Enrichment can't be tuned until the Base Fuel Table is well tuned.
    http://forums.holley.com/showthread....1379#post61379 (AE Tuning 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.

  3. #3

    Default

    Yes, I'm not actually accelerating when it happens. Being lean on the Fuel Table would make a lot of sense. I will work on it. Thanks, Danny.

    I had a chance to log this today. It's only a five second datalog (thought I had it set to 300 sec). At the light throttle, first to second shift, the actual AFR goes to 26.9 for about 1 second and then comes back down in range. Both banks of the engine go high like that. The fuel pressure stays steady at 39-40 psi, the Target A/F Ratio is 13.6, 1556 RPM. CL Comp jumps from 0 to 65% then starts ramping back down. At that particular point the Learn Table is 1%. Fuel flow ramps up to 49.8 PPH. Ignition timing is 28.4°. I'm not sure why I'm getting such a short annoying lean condition. This is just very light cruise driving around the block.

    AE vs TPS/MAP RoC Blanking: They're both set to 7.
    AE vs TPS RoC: 0, 21.1, 29.8, 37.6, 45.7, 49.2 etc.
    AE vs MAP RoC: 0, 12.1, 14.3, 16.9, 18.2, 20.3 etc.

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,676

    Default

    Quote Originally Posted by FuelieNova View Post
    I'm not sure why I'm getting such a short annoying lean condition. This is just very light cruise driving around the block.
    AE vs TPS/MAP RoC Blanking: They're both set to 7.
    You may need even lower values. It's either AE tuning, or the Base Fuel Table needs to be enriched at that specific (stubborn) area.
    This can be caused by the engine sometimes running on the same Base Fuel Table cells, for light acceleration and low RPM cruising.

    It's important to understand that we're not enriching the cruising area of the Base Fuel Table, just by increasing those Base Fuel Table cell values; if the Target Air/Fuel Ratio Table (lean AFR) & the Learned Compensation Limits % (decreased) are set properly. Some Base Fuel Table cells serve a dual purpose, depending on if the engine quickly accelerates past those cells or if the engine is cruising on those cells. When accelerating past those Base Fuel Table cells, the Closed Loop correction doesn't have the time to modify the AFR to the programmed (leaned) Target Air/Fuel Ratio, so the engine is momentarily richer (which is favorable for acceleration). When the engine is cruising on those same Base Fuel Table cells, the ECU Closed Loop correction has plenty of time to lean the AFR to the programmed Target Air/Fuel Ratio, but the (decreased) Learned Compensation Limits % won't allow the Learn Table to permanently enrich those cells. So as you see, one Base Fuel Table cell value can change the AFR in two different ways. Of course, this requires extensive Base Fuel Table tuning and manual transmission vehicles are much more sensitive to it. If this scenario is happening too close to the idle area, then the "Combo" type of Load Sensing (Alpha-N Idle Fuel) may have to be utilized.
    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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    Thanks Danny. A lean Fuel Table would make a lot of sense. I have to travel all this week, will try to work on it more next weekend. Tom

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