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Thread: Surging at 5% TPS.

  1. #1

    Default Surging at 5% TPS.

    Any suggestions on what to adjust for a surge when throttle is held steady at a very low TPS number (I.E. 5%)? The computer is overshooting the correction as you can see in a datalog. I don't know how to upload in this forum. The AFRs go lean then rich RPM follow. Andy

  2. #2
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    Zip the files & post. Always save a copy of your Config File and post it with your datalogs.

  3. #3
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    Quote Originally Posted by abmotorman View Post
    Any suggestions on what to adjust for a surge when throttle is held steady at a very low TPS number (I.E. 5%)?
    Try increasing the AE vs TPS RoC Blanking value. However, the Holley Sniper EFI will intermittently inhibit Closed Loop at idle, if the AE vs TPS/MAP RoC Blanking values are set too low.

    I don't know how to upload in this forum.
    Originally Posted by Danny Cabral
    For further assistance, post your Config File and a short datalog of this occurrence for us to analyze.
    Also, review the datalog and inform us of exactly where in the datalog (time/seconds) the problem occurs.
    Datalog & Global Files can 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 ("Go Advanced" & "Attachments").
    Your Config File is in the "Documents", "Holley" folder, "Sniper" folder, "Config Files" folder (.hefi file).
    Your Datalogs are in the "Documents", "Holley" folder, "Sniper" folder, "Data Log" folder (.dl file).
    Someone will analyze/troubleshoot the problem & offer advice.
    https://www.youtube.com/watch?v=iqHOtDNiTNA (How To Record & Email A Datalog)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2700 RPM converter, 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.

  4. #4

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    Quote Originally Posted by abmotorman View Post
    Any suggestions on what to adjust for a surge when throttle is held steady at a very low TPS number (I.E. 5%)? The computer is overshooting the correction as you can see in a datalog. I don't know how to upload in this forum. The AFRs go lean then rich RPM follow. Andy
    Surging usually occurs when the Target A/F Ratio isn't correct. The engine isn't happy there, but the program keeps trying to force the engine back to that spot. I usually see lean surging, but maybe rich surging also exists. Take a look at your Target A/F Ratio table to see if perhaps it's wrong.

  5. #5
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    Andyf, you're right. I mistakenly thought he stated "very low TPS" acceleration, but he stated steady state throttle.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2700 RPM converter, 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.

  6. #6

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    I zipped the files as recommended, thank you. I'll look at these suggestions and play around with this tomorrow. Feel free to offer any further insight. Thanks forum folks! Andy
    Attached Files Attached Files

  7. #7

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    Any update here? I'm currently having a simular issue, just my AFR fluctuates much faster at steady state cruise.

  8. #8

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    Motorman, that's an interesting looking datalog. It's very apparent the computer is chasing something, but unfortunately I don't know what. Have you checked for vacuum leaks? How is your fuel pressure? I'd send the datalogs to Holley if you haven't already.

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    Quote Originally Posted by abmotorman View Post
    I zipped the files as recommended, thank you. I'll look at these suggestions and play around with this tomorrow. Feel free to offer any further insight. Thanks forum folks! Andy
    The first thing to try is to slow down the Closed Loop "Advanced Control" You are at 3 right now, put it to 1 and test it again.

  10. #10

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    Motorman, sorry to go off topic, but did you mean to set cranking timing at 30°? That seems like an awful lot. Also, the IAC looks steady in the datalog so this probably isn't the issue, but you have a very long IAC Ramp Down Decay Rate. It's over 6 seconds. Holley recommends 2.

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