firing 'miss'

Discussion in 'Softail Models' started by Billbo, Jun 4, 2012.

  1. Billbo

    Billbo Junior Member

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    Ok heres my concern. 2001 88TC with fuel injection and stage 1 and 50K miles. Bike runs great. Run around 70 mph and when the engine is under a load it runs perfect - when totally off the throttle it runs perfect - BUT when I just 'hold' it a any speed - not on or off the gas - every now and then - like 2-3x in 100 miles, it will hicup or miss -- just one time then back to running fine. Any suggestions? Oh yeah it seems on my last 800 mile trip it happened very slightly and intermittently with all tanks of gas (filled up 6x). So I really dont think it was BAD gas but you never know - I think the 93 octane gas does NOT get used like the reg 87 and so it may be bad gas - if so there is an awfull lot of it out there on interstates.

    Thanks for your help in advance
    Bill
     
  2. Hoople

    Hoople Account Removed

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    I'm sure this bike is pre- O2 sensors but I want to hear it from you. Are you running any fuel enrichment device. How did you offset your fuel requirements for the Stage 1 way back when. Just to get an idea on the bikes general health, when was the last time you changed plugs, spark plug wires or fuel filter. It idles fine when hot or cold. The idle RPM does not "hunt" when hot. Have you checked for any historical codes. By chance when the engine misses, have you seen the check engine light flash on then off.
     
  3. Billbo

    Billbo Junior Member

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    Thanks Hoople - I bought the bike 'as is' so I dont know what was done as far as remapping. I have not seen any sorta fuel device (TFI). It does have the KN filter and semi straight exhausts. I changed plugs last year - about 2000 miles ago or so - have not replaced plug wires and have not changed fuel filter. Not sure about the O2 sensor. I am very weak in the owner/operator mechanic division!! I do the regular maintenance and thats about it. Pay other folks as needed. (sorry bout that) - at least I'm honest about it. It just puzzles me that it doesn't have a constant "miss' -- just every now and then. A couple of times it sorta sounded as if it may have back 'spit' through the air filter?????? dont think it back fired - just back "spit" - sorta sounded like air rush - for just a split second - then back to running great. And it does run great for the most part - especially when ON the gas - but just happens when I am 'maintaining' constant speed.

    Bill
     
  4. Hoople

    Hoople Account Removed

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    Since it happens so infrequently (2 or 3 times/100 miles), it's hard to even know if what you did corrected the problem. From my experience a hard infrequent miss (not a surge) is usually an electrical issue. I would start with checking for codes. You may get lucky with a historical code which may give you a clue as to where to start looking.
     
  5. Hoople

    Hoople Account Removed

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    Here is some additional info I found that may help you pull codes on a 2001 EFI. Procedure & code list. Let me know if you need more pictures.
     

    Attached Files:

  6. Billbo

    Billbo Junior Member

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    thanks Hoople. I will check it out. (is this same information included in the HD Shop Repair Manual?)

    Bill
     
  7. Hoople

    Hoople Account Removed

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    Bill, I pulled the info from a 2001 Softail HD Clymer manual so it didn't come from a genuine HD publication,,, but it should work. That Clymer procedure sounds correct to me for your MM model.