Running too Lean??

Discussion in 'Sportster Models' started by 67hat34c, Mar 8, 2010.

  1. 67hat34c

    67hat34c Active Member

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    08 1200c,

    Problem started with the low fuel light, I have been fighting with local dealer for almost 2 years on this issue. Warranty runs out this month so I demanded they make proper repairs. After some very very heated arguements over the phone they finaly called factory and verified the I was right. They replaced the Fuel pump moduel that contains the sender for fuel light. When I picked up the bike I noticed the inside of the rear exhaust pipe was gray and not black as it always has been. I did not say anything and thought well possibly when they washed the bike it cleaned it out. Ran fine but seemed a little different. Temp seemed ok etc. Went to daytona from orlando 2x last week and pipe color never changed, stayed gray. Pulled spark plugs and they were caked with a thick white residue, very dry looking. Pulled manual out and it says ok for white film. Went to Dealer yesterday and purchased new plugs and installed them myself while there. Showed old plugs to a mechanic and he said running way too lean and also he suspected valve guide leaks which is why the build up was on the plugs.

    I left the bike at Orlando HD, now waiting for their analysis.

    Mods on the bike are v&h slipons, stage 1 intake and download, all mods done at this dealer when I bought the bike new.

    Question could the fuel pump change cause a different fuel to air ratio?

    Concerned with valve and piston head damage. I would guess i put on 400 miles on it since the fuel pump moduel was changed.
     
  2. Hoople

    Hoople Account Removed

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    If the problem started exactly when the pump was changed, checking fuel pump pressure would be something I would measure.
    If fuel pump pressure was in fact low, it would result in low injector delivery. The O2 sensors would try to adjust but the limit they would be able to adjust for would be about a .3 of 1 ratio point of A/F.
    Assuming the new pump is good, just a pump change won't require a calibration.

    Check to see if you have any historical codes in the ECM. If the O2 sensor reaches its limit of range adjustment, a historical code will post.
     
  3. Jack Klarich

    Jack Klarich Expert Member

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    Id call them on the mods they have done, they should stand behind their work, that bike should not be lean unless there is a problem in fuel delivery or an intake leak back to the dealer, Jack
     
  4. 67hat34c

    67hat34c Active Member

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    found dyno chart from july 09.

    68 hp and 69.4 ft lbs tq.

    air fuel is 14 at 2600 to 3300 then 13.8 to 13.9 at 3400 to 4100 high is 14.9 at 5500
     
  5. Hoople

    Hoople Account Removed

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    If those numbers are at WOT, you are (1) Very lean, (2) Lean, (3)Crazy Lean
    in that order.
    I would suspect the wide band they used is getting a diluted sample. That 5500 RPM is over the top.
     
  6. 67hat34c

    67hat34c Active Member

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    Called shop this AM.

    Stated they did bore scope and both piston heads are fine, no pitts or holes etc.

    They plan to do leak down and compression test and will inspect valve guide seals.

    They reviewed my records from purchase through todays date and are aware they did any of the mods to the bike and are on phone with factory to discuss issues.

    If rings are an issue I cant imagine what could have caused it. I changed oil to synthetic at 1k then again at 5k, 10k and 12500 so not an oil issue unless oil pump or other issue within system.
     
  7. Jack Klarich

    Jack Klarich Expert Member

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    Hope they get u squared away, let us know what they find
     
  8. 67hat34c

    67hat34c Active Member

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    Update.

    I talked to service dept on saturday at Orlando HD and they verified dyno test showed bike running lean. However they could not tell me why. They stated no vacuum leaks and the fuel pump has proper pressure.

    This has got me stumped, how could a fuel injected bike all of a sudden start to run too lean? I will take one guess is that they may have re flashed the ECU and did not down load the proper map. They will not admitt to me what happened.

    Of course there is still the issue with burning oil, where is it comming from?

    Anyhow they are going to pull the heads and inspect.
     
  9. Big Rol

    Big Rol Active Member

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    Just curious if the bike injectors have a separate filter/screen in them. Your prob is excactly like one I had where the screens were not letting enough gas through at high RPM. Ran lean and even started to break down at high accelleration.
     
  10. Hoople

    Hoople Account Removed

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    There is not a map written that would make an engine run at 14.9 @ WOT.
    You would really have to go out of your way and force it to do it.

    You have all the classic signs of a bad MAP sensor. The ECM will only post codes for a map sensor that is Open or Shorted, Not for a sensor that has non-linear output. If the Map sensor was "stuck" at say 30 kPa, you would not post a map code and the ECM would never see any real engine load and would run lean across the board. Similar to exactly what you have.
    It may be worth checking it.