fuel milage help

Discussion in 'Engine, Fuel and Exhaust' started by 01 rk, Apr 16, 2012.

  1. 01 rk

    01 rk Active Member

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    Went riding yesterday, rode 90mi. and it took 4 gallons to fill up, less than 25mpg. Back in Feb I had a leaner map down loaded into the PC, the milage got worse instead of better, was about 30-35mpg. I did notice a smell of gas when I pulled into the shed, no visable signs of a leak, nothing wet.
    Thinking of removing the PC, SE AC and the touring slipons and see if that improves the mpg. Don't know how much of an effect leaving the true duals on will have.
    When the bike was stock I would 45-50 on the highway @ 65-70 mph.
    2006 flhtci
    If I ride anymore conservatively, I won't be moving.
    I am open to any and all suggestions.
    Thanks.
     
  2. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

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    I can only comment on 1 thing, gas stations are still useing a winter blend gas. I know my mpg gets better with the summer blend.
     
  3. Hoople

    Hoople Account Removed

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    The fuel map in the PC is probably just too fat. You did not say what the majority of the 90 mile ride was like. If pure or near pure steady 65mph, I would look at the mapping during high vacuum cells..
    Was it ever much better with the current map?
     
  4. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

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    It sounds rich to me The A/C and true duals arent the issue. You are either leaking fuel or burning it. You could unhook the PC to see how it runs and if any different. However running to lean for a long period of time isn't good for it. Pull a plug and see what it looks like. What color is the inside of the tail pipe? If its real black and sooty, its rich.
    Not sure how your bikes fuel tank is vented, check the vent tube and make sure its clear and able to vent. It probably runs down toward the seat somewhere.
     
  5. Hoople

    Hoople Account Removed

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    Did this 2006 have factory O2 sensors? And if so, does installing a PC require removing them or making them inoperative.
     
  6. 01 rk

    01 rk Active Member

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    No O2 sensors were on the bike.
    I will check the vent when I get back from my neices wedding out west.
    The plugs are new, just changed.
    The ride yesterday was 50-50 hiway/back roads.
    As I stated I got 45-50 when totally stock, I knew it would go down some when I installed the PC to make it richer so it would run cooler.
    I had dynojet down load a leaner map, they told me it is only 5 o/o richer than a zero setting. I cannot believe that is to rich.
    There must be something I'm missing.
    Thanks for the response guys.
     
  7. Hoople

    Hoople Account Removed

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    Since the bike came from the factory without O2 sensors, you don't have to worry as much during experimentation. The ECM is not focused on an A/F ratio of 14.7 like the bikes of today are. Getting 25 MPG is like riding with the choke always on and you have to be pushing fuel past the rings and diluting your oil which is not good either.

    I agree with Bodeen. If it was my bike, I would leave everything the way it is and pull (bypass the PC) as a trial. Slip-ons and an A/C push your A/F ratio maybe .75 of 1 A/F ratio point to the lean side, tops. On a pre-O2 sensor bike like yours, that is really no big thing to do as a test. If you had an exhaust analyzer, you could make small changes one at a time and take a measurement. But you don't have an exhaust analyzer, so you need to make a big dramatic change in order to find out quickly where the problem is. Your checking the results by fuel mileage readings,,, which is a very broad, not terribly accurate way to do it.

    If your fuel mileage lifts quickly & dramatically, you know the PC is just pumping fuel like crazy. If your fuel mileage only lifts like 5 MPG, you know you have an issue with a sensor, injector spray pattern, fuel rail pressure, VE etc etc. It could be something minor like an engine temp sensor telling the ECM to always choke for warm up when it is already hot. But at this point you just don't know.

    Because the PC is in-line with the Delphi ECM, I don't know if it affects the ability of the ECM to grab DTC codes. Do you currently have any stored (historical) codes. Don't go by the check engine light. Perform a WOW test. Check for codes. Write them down if there any. Clear the codes, remove the PC and ride the bike. It may throw a fresh code. With the PC in the loop, there are just too many unknowns to make a guess at what it can be at this time. Removing the PC for a test run will eliminate a big piece of it. What model PC do you have installed.
     
  8. 01 rk

    01 rk Active Member

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    Sorry for the delay in getting back to you guys on my issue , was away at a wedding.
    There are no codes showing at his time, however it has recently thrown codes.
    I have been having a problem with " loss of speedo data to the ecm", happened two times, and it registered codes for this, I cleared all the codes associated with this problem. Could this still be affecting the ECM?
    Hoople you will have to clue this old guy in on the WOW test, not up on acronyms you guys use.
    I will disconnect the pc this weekend and let you know if there is a change.
    Thanks again for all the help so far.

    ================================================

    Sorry did not notice your last question Hoople.
    I have a PCIII installed. I have talked extensively to Dyno Jet about this, as I stated previously they tell me my map is only 5% above the stock fuel setting

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    Last edited by a moderator: Apr 26, 2012
  9. 01 rk

    01 rk Active Member

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    I disconnected the PCIII rode 102 miles mostly back roads at 40-55 mph, no interstates, filled up, 2.48 gallons that's 41mpg, that's with two up riding, much better without the PCIII.
    The question now is do I try to lean out the PC more, or should I remove the SE AC and the touring mufflers and reinstall the stock equipment?
    Again any advise will be appreciated.
     
  10. R. Lewis

    R. Lewis Senior Member Retired Moderators

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    JMO ---- get rid of the pc and get a fueler you can manipulate as you go.
    As far as the gas smell - more than likely unburnt fuel in the system and "dumping" back into your engine. The slips and a/c will not affect the bike if you keep the pc unplugged until you get another fueler. Thats the problem with the pc, when it does act up , you have to go back to a dealer/Indy to have it looked at.