Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: How to diagnose most Buell EFI problems

  1. #1
    Member
    Join Date
    Aug 2015
    Location
    Boynton Beach, FL
    Posts
    58

    How to diagnose most Buell EFI problems

    I have added this section below to the troubleshooting page at rev-mo.com/efitroubleshoot. Instead of randomly replacing parts based on a hunch or something you read online you can actually see what each sensor is feeding the ECM and how it effects the fueling, in real time. It may not tell you exactly what the problem is, but it will tell you what it isn't. If you seek help from others armed with this information it is extremely helpful too. The tutorial for using the Data Channels page of Ecmdroid is at rev-mo.com/livedata.



    PERFORM DIAGNOSTICS USING LIVE DATA

    The Buell ECM makes adjustments based on data it receives from sensors located on the bike. If the data from a sensor isn't accurate the bike won't run right, or maybe not at all. There aren't very many sensors and viewing the data is easy, so the process of elimination doesn't take long. Below is a screenshot of how you can set up your Data Channels Page of EcmDroid which will allow you to troubleshoot or narrow down a vast majority of EFI related problems WITHOUT spending money on parts or getting your hands dirty. There are numerous other parameters that can be viewed but this is a good place to start.

    Troubleshoot screen shot.jpg

    TPD (Throttle Position Degree)

    On pre-2008 models, when the idle is adjusted to about 1100 RPM with engine fully warmed up, this should be about 5 degrees. On 2008+ models it should be about 4 degrees. When the throttle is moved it must change at a steady rate without any dead spots or spikes. At WOT it must read 85 degrees.

    AFV (Adaptive Fuel Value)

    In factory closed loop operation, the ECM will make adjustments to the overall fuel delivery based on O2 sensor data. At or near sea level this number should be close to 100. If it is significantly higher than 100 it could be a sign of a fuel delivery problem so it would be a good idea to measure fuel pressure (on 1125 and 2010 XB models fuel pressure can be viewed on a data channel). If this number is significantly lower than 100 you can isolate the problem by disabling closed loop which takes the O2 sensor out of the equation. Remember that in closed loop operation, the ECM will use AFV to adjust for issues caused by mechanical problems. It is also common for this to be at an unnecessarily low value, even when all sensors are working properly.

    IAT Corr (IAT Correction)

    This shows you the percentage of fuel compensation the ECM is making based on the Intake Air Temp sensor. Generally speaking, it should be more than 100 in cold air and close to 100 on warm days and while riding. With factory settings the ECM will lower the IAT Corr (reducing fuel delivery) when the air temperature reading is abnormally high, which actually exasperates the problem.

    WUE (Warm Up Enrichment) and CLT (Engine Temp)

    Warm Up Enrichment is based on engine temp or CLT (measured by the head temp on air cooled models, and coolant temp on 1125 models). When the bike is completely cold the CLT should read ambient temperature. As the bike warms up the CLT should increase and WUE should decrease until operating temperature is reached. At this point the WUE should be close to 100. If, for example, the head temp sensor on an XB is loose or defective the ECM will continue to enrich the fuel delivery unnecessarily which will be seen as a constantly high WUE number. Also, the calibration or "learn" mode for AFV will not be active until a minimum CLT number is reached (on XB models the factory setting is 130). Without accurate temp sensing the engine will never run correctly.


    Hopefully this will help save people a lot of money and headaches.
    Last edited by upaero; 03-02-2021 at 04:56 AM.

  2. #2
    Senior Member
    Join Date
    Jan 2016
    Posts
    685
    Good info to have. Thanks

  3. #3
    Senior Member 34nineteen's Avatar
    Join Date
    Mar 2015
    Location
    lunatic_fringe is ___________ my spirit animal
    Posts
    3,110
    Thanks also for that info. That post was super helpful and I learned a few things.

    1. I didnt know you could have more than 4 data streams in ECMDroid.
    2. I didnt know about the max setting for the TPS
    3. Its very helpful to know those are the recommended data streams to be monitored, and the results that we should be looking for.

    Much appreciated!!!!!

  4. #4
    Senior Member Cooter's Avatar
    Join Date
    Dec 2012
    Location
    Crawling up your skirt
    Posts
    9,012
    Thanks for hand delivering this post to our little forum! Super helpful and I'm sure it will be referred to often!

    Thats site has a TON of useful info

  5. #5
    Senior Member outthere's Avatar
    Join Date
    Jun 2018
    Posts
    619
    outstanding thanks

  6. #6
    Senior Member
    Join Date
    May 2018
    Location
    Vancouver WA
    Posts
    114
    Can I add the fuel pressure sensor to an 08? I have considered adding the rear o2 sensor and 2010 programing any hints on this would be great!

  7. #7
    Senior Member Cooter's Avatar
    Join Date
    Dec 2012
    Location
    Crawling up your skirt
    Posts
    9,012
    Quote Originally Posted by cvc View Post
    Can I add the fuel pressure sensor to an 08?
    Remove throttle body and fuel rail, drill and tap to 1/8FPT, add sensor and gauge. I don't know if the Buell ECM has an input for that or why it would care.


    Quote Originally Posted by cvc View Post
    I have considered adding the rear o2 sensor and 2010 programing any hints on this would be great!
    You mean front and yes you can. It would be a very marginal benefit but easy to do. Add it, check the "Front O2" box and play around.

  8. #8
    Member
    Join Date
    Aug 2015
    Location
    Boynton Beach, FL
    Posts
    58
    Quote Originally Posted by cvc View Post
    Can I add the fuel pressure sensor to an 08? I have considered adding the rear o2 sensor and 2010 programing any hints on this would be great!
    Technically you can, but your pump is already regulated by a mechanical fuel pressure regulator so the sensor data would only be good to look at. Adding another O2 sensor does nothing for you either. Adding a baro sensor and optimizing your fuel delivery will make it run better and cooler with minimal effect on fuel economy. What's your AFV at now and what exhaust system do you have?

  9. #9
    Senior Member
    Join Date
    May 2018
    Location
    Vancouver WA
    Posts
    114
    Has a hawk muffler and I cant find my ecm spy cable when i went looking yesterday so time for a buelltooth when I last checked afv around 100 but who knows now jumper shows no codes.

    Yes front not rear sensor, was putting front sensor bung in even if unused at this time before having the header ceramic coated bright silver and the comfort kit heat shield black. I should be doing three at the same time to cut cost per unit as the coating outfit quoted the same cost for one bike header or a set for a V8 chevy.

    if the 2010 and 1125 have FP sensors then the computer should be able to read it, Just thought that a quick reading through ECM spy or Buelltooth would be quick and easy in the future.

    Baro sensor looks like a Vortec , 3.8l or LS gm MAP sensor is it the same part? and thanks for the sugetion if I am taking it apart then might as well do them all.


    Cooter how easy is it to see your FP gauge with the bike together? A mechanical gauge is easier to do on the bench but curious about reading it on the bike.

  10. #10
    Senior Member Cooter's Avatar
    Join Date
    Dec 2012
    Location
    Crawling up your skirt
    Posts
    9,012
    I don't run a fuel pressure gauge. I don't see the point. Pretty boring staring at a gauge that sticks at 49psi all day, everyday, all the time.
    My TB was off so I added a schrader valve to my fuel block for ease of diagnosis if I ever have an issue.
    374A0A32-3779-4E94-84AE-A9298C025DBC.jpg



Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •