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Thread: Unknown Issue/Bogging Out

  1. #1

    Default Unknown Issue/Bogging Out

    Engine was running smoothly until about two days ago. Now I'm having a problem with intermittent bogging out while driving. While idling it runs OK, a bit shakily as if barely out of time, but it runs. Regardless of RPM, the AFR reads 35.6. Because I have had problems before, I started by checking fuel pressure (in between each filter and going in/out of the EFI unit). Pressure was stable and within expected ranges. I then pulled and swapped the WBO2 sensor. The problem persisted. I enabled & disabled Learn & Closed Loop. It went from stable at an idle, to coughing out & dying within a couple of minutes. The enclosed datalogs are from today, the engine did not bog out, but did run rough, and when I stopped, it remained at a high idle until I revved the engine a little bit.
    Attached Files Attached Files

  2. #2
    Join Date
    Nov 2014
    Location
    Ont. Canada
    Posts
    1,419

    Default

    You've already found the problem. Your WBO2 sitting at 35.6 is not good. Call Holley to get a new WBO2 sensor.

  3. #3

    Default

    I bought a couple of extra sensors last time I had troubles. Tried both of them with the same result (35.6). My last issue (https://forums.holley.com/showthread.php?45718-Engine-dies-under-acceleration) had the same reading on the handheld of 35.6, but the sensor was not the cause. Is there anything else which could cause the problem? Or possibly something wrong with the settings caused the first one to go bad, and the unit is not reading the replacement?

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,893

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    Originally Posted by Danny Cabral
    Is the Sniper EFI Learning? Is the ignition timing synchronized? Is the fuel pressure 58-60 psi (LINK)? IAC Position
    of about 5% at hot idle? Check for ignition misfires/RPM signal problems, exhaust leak upstream of WBO2 sensor,
    or if the WBO2 sensor (or other sensor) has failed and corrupted the Learn Table. Look at the Data Monitor/Gauges.
    Also, the Holley Sniper EFI will intermittently inhibit Closed Loop at idle, if the AE vs TPS/MAP RoC Blanking values are set too low.
    http://documents.holley.com/techlibrary_199r11259.pdf (Holley Sniper EFI Help Manual)
    http://documents.holley.com/199r11369.pdf (Holley Sniper EFI Troubleshooting Guide)
    https://forums.holley.com/showthread...8356#post88356 (Holley Sniper EFI Fuel Pressure Tester/Gauge)
    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

    Default

    I had the same issue. Three different WBO2 sensors read 35.6 AFR on Closed Loop. Car ran fine in Open Loop. I also tried the WBO2 test with it on the bench and engine running. Holley is having me send in the unit for testing.

  6. #6

    Default

    Sounds like the ECU has lost its ability to read the wideband O2 sensor. Could be a cable or connector issue or could be something else. I think you'll have to send it in. You could try to upgrade the firmware to see if that fixes it, but that's probably a long shot.

  7. #7
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    22,893

    Default

    Yes, first try reflashing the ECU firmware. If that doesn't correct it, then contact Holley Tech Service (LINK).
    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.

  8. #8

    Default

    I'll check the wiring as soon as I get the chance, then give the firmware a go. It might be a few days before I get back with the results, but I'll post as soon as I can. Thank you for your help so far!

    UPDATE #1: So finally got around to it. Verified the condition of the wiring, checked for exhaust leaks, reinstalled the firmware. Still in bad shape. So I contacted Holley and I'll be sending the unit in for them to have a look at. This may take a while, but I'll let you all know what I find out. Thanks again.

    UPDATE #2: Got it back, installed it, still borked. So now I'm looking for a copy of my sales receipt and sending it back one more time.

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