Fuel injector problem- again

Discussion in 'Engine, Fuel and Exhaust' started by Sky Hook, Jun 6, 2010.

  1. Sky Hook

    Sky Hook Member

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    Rear injector replaced about 8k ago (took the HD mech 5 hours to figure out the injector was bad, another 3 hrs on the dyno to tune afterward). Now the symptoms are back again- OK acceleration, but misses during steady speed, fuel mileage down, backfires and pops. Took the plugs out today, the rear plug is fouled. Think it's just a bad injector (again) or could it be the ECM?
     
  2. glider

    glider Veteran Member

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    Could be a bad wire to the injector too but that wouldn't show as a fouled plug.

    5 hours to diagnose a bad injector???.... he should turn in his tools and become a cook.:D
     
  3. Jack Klarich

    Jack Klarich Expert Member

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    Or hit with a hammer, I would ask for a refund and find another dealer
     
  4. Sky Hook

    Sky Hook Member

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    I can do regular maintenance (fluids, plugs, etc) but haven't replaced injectors. I have the HD service manual- how difficult is it to replace the injectors?
     
  5. Hoople

    Hoople Account Removed

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    If the plug is fouled that tells me it is getting fuel and no spark. Lack of injector would not cause backfire and pops but erratic spark would. Don't jump to conclusions like an ECM. That will cost you a lot of wasted money.
    Have you checked for any DTC's.
     
  6. glider

    glider Veteran Member

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    Have you tested the resistance in the plug wires or replaced them to try to isolate the problem? Fouled plug is missing ignition, not fuel.
     
  7. Sky Hook

    Sky Hook Member

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    Thanks for the tips. The spark looks strong (bike actually started with the plug wire off and laying near the tip).

    No codes. The last time this happened, the tech told me the injector was open all the time, letting too much fuel in- thus causing the fouled plug, poor mileage, etc. Does that make sense?
     
  8. glider

    glider Veteran Member

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    It still could be an intermittent spark if the wire is bad. Best to test the resistance and move the wire around to see if it fluctuates while moving it.
     
  9. Hoople

    Hoople Account Removed

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    Yes, that could happen. But if an injector sticks wide open, a TON of fuel would be going in. Fuel would be dripping out the pipe when it was going down the street,

    You could always swap injectors and see if the front spark plug now goes black. That would be a quick and dirty way to test it.
     
  10. Bud White

    Bud White Well-Known Member Retired Moderators

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    I agree with Hoople when a injector goes wide open they will barely run and end up with a ton of gas in oil