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Thread: Troubleshooting Poor Performance

  1. #1

    Default Troubleshooting Poor Performance

    Any suggestions to help troubleshoot a car that runs well at times and poorly at others (without any changes in between)? I dyno tuned the car and put the ECU in Open Loop to ensure it wasn't the WBO2 sensor causing the problem. But the problem persists. When is runs poorly, it will start fine, leave off idle fine, stumble between 2500 & 4500 RPM, clear out to 6000 RPM, then fall on its face again. Again, the problem is intermittent. Thank you!

  2. #2
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    19,270

    Default

    Record & review a short datalog of this occurrence. It will reveal the problem, especially when overlaying the datalog onto your Global File.

    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://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.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  3. #3

    Default Uploading File

    I'm attempting to upload a short Datalog (1MB) & Global File to get assistance with poor performance, but I receive an "invalid file" error message for both the .dl & .hefi file extensions. What am I doing wrong? Thank you.

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    19,270

    Default

    Datalog & Global Files must be linked to a document hosting website. I use Dropbox.com.
    Files can also be "zipped" (compressed zipped folder) & attached directly to a forum post.
    Your Global File is in the "Documents", "Holley", "HEFI V4", "Global Files" folder (.hefi file).
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  5. #5

    Default Poor Performance Follow-up - Datalog & Global File Links Attached

    Attached are links to the two files. As you will see, the 6-10 second interval has what seems to be a significant miss. Can you decipher if it's ignition only, or a larger issue with the tune or EFI system? Thank you in advance!
    Tune file link: https://www.dropbox.com/s/7t41dflzn2...inal.hefi?dl=0
    Datalog file link: https://www.dropbox.com/s/1z7p7ez6sc1x9v9/Log.dl?dl=0

  6. #6
    Join Date
    Nov 2014
    Location
    Ont. Canada
    Posts
    938

    Default

    Take a look at where your MAP is at WOT. That doesn't look right. Then look at where that MAP setting would put it in the Base Fuel Table. It's in an area that is not giving it any fuel. Look at your Base Fuel Table in the Fuel Graph form, that looks very strange to me, not smooth at all. Look at my Fuel Graph, looks nothing like yours.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  7. #7
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    19,270

    Default

    The 4th & 5th paragraphs address blending the Fuel Graph smooth, but the entire post is very informative:
    http://forums.holley.com/showthread....2523#post62523 (Holley EFI Tuning Tips & Information)
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

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