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Thread: Need fine tuning some issues please.

  1. #1

    Default Need help fine tuning some issues please.

    So I've been reading as much as I can on this forum and have solved the bulk of my idle and cruise issues, this site is a huge help. This my first attempt and tuning EFI and realize I still have a lot to learn. I have the Terminator TBI system on a 496 BBC, RPM Air-Gap intake with 1" Spacer.

    I still have one nagging issue that I've not been able to fix yet. Under rapid throttle movement to WOT (1st gear only, example - drag launch) I get a lean bog once the RPM gets above about 3500, the engine goes dead lean and basically goes into a limp mode and will stumble with any throttle input and needs to idle about 20-30 seconds before it can be driven again. The engine also does this if I'm cruising down the road at a speed low enough that going WOT will allow the transmission to drop into 1st gear. However, this only happens when going into or through 1st gear, down shifting from 3-2 and 4-3 does not cause a lean condition, even with rapid throttle movement to WOT.

    I feel my Base Fuel Table is tuned very close, there are a lot of areas of the Learn Table that have no values (I assume these are very close and are done) and areas that do have values are small, +/- 2-4%. Unless I have misunderstood how Learn works, I took this meant the Learning was mostly completed. The driveability is very good and so is WOT performance except for the areas mentioned above.

    I've played with AE in both TPS Rate of Change and MAP Rate of Change with only marginal improvement. I continued to increase MAP Rate of Change by adding 15%, which I thought was a lot, and it only made a small improvement.

    So should I focus on the Base Fuel Table for this lean bog in only 1st gear or is this tuned in AE?

    One other question, I have the Holley fuel pressure regulator and I found that there is no vacuum signal attached to it. Do I need a vacuum signal from the Terminator to the FPR?
    Last edited by mblum; 04-26-2020 at 10:42 AM.

  2. #2
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    Quote Originally Posted by mblum View Post
    Unless I have misunderstood how Learn works, I took this meant the Learning was mostly completed.
    When the Learn Table values stop making significant changes, the ECU is finished self-tuning. The purpose of the Learn Table is not to achieve similar values, high/low values (0% or 100%), or any value in particular. It's simply indicating the amount of tuning applied to the Base Fuel Table. Read this thread (LINK), that's what it's all about.

    So should I focus on the Base Fuel Table for this lean bog in only 1st gear or is this tuned in AE?
    Yes. Once the Base Fuel Table is well tuned, there shouldn't be much need for a lot of Acceleration Enrichment (especially not AE vs MAP Rate of Change).

    I have the Holley fuel pressure regulator and I found that there is no vacuum signal attached to it. Do I need a vacuum signal from the Terminator to the FPR?
    If your fuel pressure regulator is located at the front of your vehicle, then yes, attach the vacuum reference hose. That's what it's for.
    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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    Datalog the event. Then look at the CL Status. You will notice it goes into Open Loop with rapid throttle movement. This means it'll never Learn in this area. So you'll have to manually tune this area. And by your description of the event, I'd look at a rich booge. A rich misfire will show as lean.
    Last edited by 81 TransAm; 04-26-2020 at 11:40 AM.

  4. #4

    Default

    Thank you fellas for the quick response. I'll attach a vacuum line to the FPR and work on manually tuning this area. Your correct, the system does not spend much time in this area of the Base Fuel Table. It doesn't help that traction in 1st gear is non-existent on the street, so the engine revs very quickly through this area.

  5. #5
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    Overlay the datalog onto your Global File, and pay special attention to the center paragraph in blue print:
    Originally Posted by Danny Cabral
    Quick Datalogger Information:
    Always provide data, not just symptoms. Is the AFR & ignition timing optimized? Overlay the datalog onto your Global File.
    Ensure the Target A/F Ratio table is properly programmed for your engine. Ensure the ECU is "Learning" (Learn Table LINK).
    Scroll through the datalog to the problem area. Then look exactly where this happens on the Base Fuel & Timing Tables. Scrutinize:
    RPM, MAP, MAT, TPS, CTS, IAC, Target AFR, AFR Left, CL Comp, Ignition Timing, Duty Cycle, Fuel Flow, Fuel Pressure & Battery.

    Using the Holley EFI software (LINK), look at where the live cursor moves to during this occurrence, and
    manually tune that area of the Base Fuel Table (enrich or lean) & Base Timing Table (optimize ignition timing).


    I find the most helpful datalog function, is overlaying the datalog on your Global File.
    I'm in the habit of using the datalog Overlay feature every time I review a datalog.
    Click on "Datalog" (on the top Toolbar), "Activate Overlay", then "Open Data Log".
    You can literally "playback" a recorded event, and watch it as it happened on any screen.
    Minimize (shrink) the datalog window, and move it to the bottom of any Global File screen.
    Then click & scroll anywhere on the datalog, and watch it playback on your Global File (EFI software).
    http://documents.holley.com/techlibr...9r10543rev.pdf (Holley EFI Datalogger Instructions)
    https://forums.holley.com/showthread...s-amp-Datalogs (Datalog & System Log Information - Read "NOTES")
    https://www.youtube.com/watch?v=iqHO...C6FEA0BB99AF17 (How To Record & Email A Datalog)
    https://www.youtube.com/watch?v=q7OZUXLRS1Q (How To Record A System Log & Diagnose A No-Start Condition)
    https://forums.holley.com/showthread...7531#post77531 (Closed Loop Datalog Tuning - Posts #2, #4 & #6)
    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've attached the vacuum line to the FPR from manifold vacuum, can someone explain what function the vacuum signal has on the FPR?

  7. #7
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    https://www.vaporworx.com/documentat...re-regulators/ (Vacuum/Boost Referenced Fuel Pressure Regulators)
    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.

  8. #8

    Default

    This problem has been fixed and wanted to post an update in case anyone else has this issue. The fix is probably obvious for an experienced tuner, but for this newb it took some datalogging before the slapped me in the face.

    My issue ended up being I was hitting the rev limiter set in the MSD E-Curve distributor. My ignition is not being controlled by the Holley EFI (although I really wish it was), the reason for this was the MSD distributor was already on the car and was only about a year old when I decided to go EFI, so I've been tuning the ignition separately form the fuel.

    I had set the rev limiter at 5700 RPM when I first started to tune the car a few months back, as the tune became more "dialed in" the car ran much better and would rev much quicker, especially in 1st gear for obvious reasons. Being the ignition rev limiter was not set in the EFI I wasn't paying close attention to it. My shift points on the 4L80E are at 5600 RPM for all gear changes, on the 1-2 shift the RPM would climb fast enough to tag the ignition rev limiter before the shift was completed. When ignition was cut the fuel continued to flow and was not being burnt causing a false lean, which the ECU tried to compensate for by adding more fuel.

    So the final fix was to set the 1-2 shift to occur at 5400 RPM (instead of the 5600 I had before) to give the "mechanical" components time to react quick enough to complete the shift before hitting the rev limiter.

  9. #9
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    Thanks for the update.
    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.

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