Hard Starting Only When Hot

Discussion in 'Dyna Models' started by Kjay, Jun 26, 2010.

  1. Kjay

    Kjay Member

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    Things were fine until last week I stop to get gas after riding maybe 40 miles or so and when I was ready to go the bike won't start. After waiting say 15 or 20 minutes, it starts fine. It doesnt do this all the time and never when I first start with a cold engine. Only after I have been riding awhile sometimes it will start right away but seems after the 4th or 5th stop nothing, it just cranks like it not getting any gas or not firing. I put in new plugs and air filter. Now I am going to try an iginition coil and fuel pump relay that I just so happen to have laying around that I know is good. Maybe that will solve my problem but I don't think that is it but I think its worth a try seeing how I have them here already. The bike is a 2003 Dyna Super Glide stock engine. Does anyone have any suggestions as to what might cause this or has it every happen to anyone else.
     
  2. BUBBIE

    BUBBIE Well-Known Member

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    Kjay,

    :newsmile105: bad gas / old wires..

    If you haven't installed new ones in a while? Do so.... BUT first, Remember the plug condition when you LOOKED at them..... How were they are firing?... Were they good and White(lean condition) or do they have a tinge of y-brn on the electrode porcelain(good in my book) or are they sooty black? before you replaced them

    The spark plug wires I would replace with HD new stock ones just because of the age of bike IF Not already done.

    Get back and more will depend on your findings.. I would NOT throw Major parts at it unless necessary.... You can spend a ton of money to only find the Least expensive things are the problems..

    signed....BUBBIE:D
     
  3. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    Hard starting when HOT, but the engine spins up fine, means either lack of fuel or weak, no spark. If your Dyna is EFI, your fuel pump is losing prime/pressure due to fuel line leak...look here:

    http://www.hdtalking.com/diagnostic...lated/979-engine_dies_and_runs_in_spurts.html

    If ignition is suspect, crank position sensor CKP or other throttle position sensor TPS or ignition coil, but then do you have any diagnostic codes...i.e. the red Key symbol indicating this?

    http://www.hdtalking.com/diagnostic...ed/728-04_07_hd_dtc_codes_and_activation.html

    It would be really helpful if we knew more about year and the bike's recent history prior to the symptoms.


    If hard starting was engine barely or doesn't turn over, it would mean two things, your battery should be back up to full and with surface charge reserve of 14V (2 volts over full charge 12.6 or so) so battery "should" not be an issue IF charging ckt and connections are sound. BUT, more compression and starting load means more strain and stalled current draw on the starter....all things being equal. "Usually hard starting is a tossup between aged battery or bad starter depending on duty of service time and stress wise.

    If battery was ever deeply discharged and is "old" I would give it the "86". But if it has been maintained and simple voltage checks running and just after starting give the electricals and connections a once over a clean bill of health...you have a bad starter...and need to check the current draw and temps of all the primary wires.
     
    Last edited: Jun 26, 2010
  4. iceman

    iceman Member

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    In the past I've had this problem with a weak coil or poor fuel tank venting.
     
  5. gunnut

    gunnut Junior Member

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    I had this problem,and it went on for a while,it turned out to be the battery in the end.Whole lot cheaper than coils and stuff.My dad taught me always to look at the simple things first,9 out of ten times,they are the problem.
     
  6. Kjay

    Kjay Member

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    Well after checking the codes I came up with a few as follows:p0134, P1356, U 1092, U1255 and I think the more serious one would be the O2 Sensor but would that actually cause just hard starting? Does no combustion mean I am running on one cylinder?
     
  7. glider

    glider Veteran Member

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    No combustion doesn't mean it isn't firing. The ION sensing on the bike is detecting that there is an abnormal resistance in one of the secondary ignition circuits (coil/plug wire/plug) and it's setting a code for that.
     
  8. Kjay

    Kjay Member

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    Can an open or not responding O2 sensor cause this hard starting problem after the engine is hot?
     
  9. glider

    glider Veteran Member

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    I doubt that is the case but that would set a code that you could retrieve.
     
  10. Hoople

    Hoople Account Removed

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    When you say Stock, you mean absolute Stock. No fuel pack, no pulse stretcher, no nothing.