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Thread: Bad WBO2 Sensor?

  1. #1

    Default Bad WBO2 Sensor?

    This is my first post, so hello and bare with me. I have a Superformance 427 Cobra with a BluePrint Ford 427 CI stroker that came complete with the Sniper EFI system. Got it in September 2020. I've put about 2,000 miles on it. It has been running progressively worse and worse the past few weeks, now to the point of not being driveable (unless I disable Closed Loop).

    The best way to describe the symptoms is that at light throttle (<10% TPS) there’s a significant power loss, engine stumbles making the car lurch, and a very unhappy rough exhaust sound almost like a Jake Brake. I also noticed the Sniper trying to run more lean in these moments than normal (like 15.5 AFR instead of high 13s or low 14s). When this first started happening, idle and hard throttle would be fine, but if I kept the throttle in basically the same spot the problem would get worse.

    It started happening most often just cruising with the throttle barely cracked open, especially when fully warm. Again, idle would be OK, and hard on throttle would be OK. But light cruising throttle was a nightmare. Starting over with the Wizard helped the first few times (weeks ago) but after after about 20-60 miles the problem came back. Then the problem started coming back quicker & quicker, and it started to want to die even just idling at stoplights, requiring a throttle blip to avoid stalling. Today it started coming back right away after starting over with the Wizard. If I disable closed loop (run in Open Loop), the issue goes away completely, the engine runs smoothly, idles fine, cruises fine, but definitely a little compromised on power when I get on the throttle (which I assume is to be expected). Does it seem like the WBO2 sensor may have gone bad, since the engine runs smooth in Open Loop? Any other ideas?

    I've searched a lot on this forum for similar problems/solutions and finally decided it was time to join and post. I hesitated because I don't have a PC and I have seen that the first thing people talk about is using the EFI software. At this point, I don't really have a good GCF file because I didn't start downloading them until the issue started happening and I was starting over. Any guidance is much appreciated. Thank you for your time.

  2. #2
    Join Date
    May 2019
    Location
    Ct
    Posts
    519

    Default

    For the best help, I'd recommend you take a datalog of the incident and in Windows zip it into a folder with your downloaded GCF Config File and attach it here.

  3. #3
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    28,301

    Default

    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 Logs" folder (.dl file).
    Someone will analyze/troubleshoot the problem & offer advice.
    https://www.youtube.com/watch?v=iqHOtDNiTNA (How To Record & Email A Datalog)
    Overlay the datalog onto your Config 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 Config 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. When the engine is tuned & running well, you should decrease the Closed Loop & Learned Compensation Limits % to lock in a good tune.

    Using the Holley Sniper 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 Config 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 Config File screen.
    Then click & scroll anywhere on the datalog, and watch it playback on your Config File (EFI software).
    http://documents.holley.com/techlibr...9r10543rev.pdf (Holley EFI Datalogger Instructions)
    https://forums.holley.com/showthread...s-amp-Datalogs (Datalog 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)
    https://www.youtube.com/watch?v=rHjLwJQ45Kw (Holley Sniper EFI Datalogging Tech Video)
    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.

  4. #4

    Default

    Could be the wideband O2 sensor, could be something else. Hard to say without any data. If the engine has a PCV, you should remove it and install a breather to see if that solves the problem. Light throttle will be high vacuum and perhaps the PCV has failed.

  5. #5
    Join Date
    Feb 2020
    Location
    Wheeling, WV
    Posts
    1,120

    Default

    Quote Originally Posted by black427cobra View Post
    Any guidance is much appreciated. Thank you for your time.
    Do you work on your car yourself? If not, I suggest you find a local technician that's familiar with the Holley family of EFI software and have them diagnose it for you.

    If you do your own work, start by viewing a datalog of the event, it will have a lot of clues in it. I'm assuming you don't have a datalog of the event based on your original post and now that you've done the unforgivable and rerun the Wizard multiple times a lot of the original clues are gone, unless you saved a datalog and the original tune. I suggest you follow the previous advice given, watch the Closed Loop Compensation as a clue, and you can test the WBO2 via this link https://www.youtube.com/watch?v=rmnx...nel=AEMEMSTech

  6. #6

    Default

    Thanks guys. I sincerely appreciate the feedback.

    It sounds like I really need to do a datalog and upload that and the GCF for you guys to be able to take more of a virtual look under the hood. The car is really unhappy right now and I worry that running it could do damage, but I suppose just a short run with a datalog would be worth it do get some progress.

    Danny Cabral, I greatly appreciate your wisdom and guidance all over this forum. Unfortunately, I don't have a Windows machine, so I can't use the Holley EFI software to look at the tables myself.

    AndyF, it definitely has a breather.

    a b c, I wouldn't consider myself a true mechanic, but I try to do as much work on my vehicles as I can, especially routine things like changing oil, etc. I feel confident I could swap an WBO2 sensor, but at some point I do need to find a good local technician who is familiar with the Sniper. I'd like to test the WBO2 sensor with the method you linked to. Can I do that with just the AFR reading on the Sniper handheld? I suppose if the ECU itself is bad (which I've heard is not uncommon) that could give a false reading, but at least it's somewhere to start.

  7. #7
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    28,301

    Default

    When you have a Sniper EFI problem, it's time to buy an inexpensive used Windows laptop (to download Sniper EFI software, retrieve the GCF from ECU, engine tuning & Datalogging).

    http://documents.holley.com/199r11031r.pdf (Holley Sniper EFI Retrieve, Save & Upload GCF - SD Card & Laptop/PC Usage, Pages 72 & 73)
    https://forums.holley.com/showthread...102#post231102 (Related Forum Thread)

    I always keep a recent copy of my Global File in an email. You can also keep a copy of it on your computer's Desktop screen. Others keep a copy of it on a USB flash drive or on the 3.5" touchscreen's SD card. The 3.5" TSLCD & Digital Dash can retrieve your Global File from the ECU.
    https://documents.holley.com/199r10751rev1.pdf (Holley EFI 553-108 3.5" TSLCD Instruction Manual - "ECU Globals", Page 31)
    https://documents.holley.com/199r10746rev1.pdf (Holley EFI 553-106 Digital Dash Instruction Manual - "Global Config", Page 33 & 34)

    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 Logs" 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: 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

    Hey everyone. I just wanted to give an update in hopes it might be useful to someone with similar problems in the future. I did finally get my hands on a Windows laptop and got the Sniper software installed. I also downloaded the latest firmware for the Sniper and updated that as well for a clean slate. Then used the Wizard and created a fresh GCF. Then, I made sure to follow the instructions on page 13 of the "Quick Start Manual" titled "First Drive" very carefully while also datalogging.


    Start the car and let it idle. Let the car get up to operating temperature coolant temperature over 160°F) so that the self-tuning can occur. If you’d like, have a passenger look at the handheld display and look at the “CL Comp” value. Once this value is close to zero, the self-tuning process has been completed in that engine operating area. Next, put the car into gear if it’s an automatic and let it run there. If the vehicle has air conditioning, you can turn it on, which will put the engine in a different tuning area as well. Next, slowly accelerate from a stop. If the transmission is a manual, do some slow clutch engagements away from a stop. Then cruise the vehicle at a steady speed, varying the speeds after a few minutes of steady driving. You can also drive in different gears. What you are trying to do is run the vehicle at different engine speed and loads. After driving under various driving conditions, you can perform some harder acceleration runs including WOT runs. After this, the Sniper EFI will have performed most of the self-tuning required for a good running engine. As Closed Loop percentage trends towards 0% in all driving conditions, the Sniper EFI has learned enough to transfer Learning To Base (Base Fuel Table) and lower the Learned Compensation Limits. Reference the Sniper EFI instructions for further details on Transferring the Learn Table and lowering the Learn Comp Limits.
    To my surprise and relief, the car ran absolutely perfectly and has ever since. It's actually running better than ever. Seems like it was a bad map, possibly from rushing through the CL Comp process after going through the Wizard, or maybe even the firmware update had something to do with it. Hard to say, but I'm so thankful it's not only back to normal, but better than ever, and the fix cost $0.

    I now download my GCFs after every drive, and have run a few datalogs. I also have access to a laptop with the software on it, so if any issues should arise in the future I am ready to tackle it. Thank you all for your help. While we didn't exactly figure out the issue, your feedback definitely got me moving in the right direction. Next time I go for a drive I'll take a datalog and upload it and the GCF in case anyone's interested.

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