question on tps

Discussion in 'Touring Models' started by old glide, Jun 22, 2011.

  1. old glide

    old glide New Member

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    hello. just wondering if anyone has any thoughts on this issue i"m having.
    once my bike is hot it runs like (EDIT).
    sputtering when trying to pull away from a stop. ( have to play with the throttle to get it moving ) once i"m moving, if i hit the throttle hard, i get the same sputtering for a few seconds.
    i recently changed out my grips and was wondering if by letting loose the throttle cables, would that somehow affect the tps and cause this issue??
    dealer thinks it is my engine temperature sensor.
    99 road glide with efi
    thanks, any ideas would be helpful

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    Last edited by a moderator: Jun 22, 2011
  2. Hoople

    Hoople Account Removed

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    Yes, it could be the TPS. But it could also be other things...
    Before I blindly started changing any parts, I would first check the fuel pump pressure. If it was low, once the engine came off "choke enrichment", it would have problems.

    The ET sensor is easy to check with a meter. Measure it cold, then measure it hot. Compare the readings to the service manual spec. But I doubt if it is the ET sensor as the dealer suggested.
     
  3. Breeze3at

    Breeze3at Well-Known Member Contributor

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    If it started right after you changed the grips, I'd look at what you could have done there to cause the problem.
     
  4. glider

    glider Veteran Member

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  5. 03ultra45385

    03ultra45385 Active Member

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    TPS can be checked with an ohmeter. Service manual id's the three wires at the ECM. Resistance should drop as throttle is opened once you find the right two wires of the three coming from the TPS.
     
  6. RibEye

    RibEye Junior Member Contributor

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    More symptoms and characteristics may help diagnose:

    1. Does the stuttering tend to occur only when accelerating from stop or also from some fixed cruising speed? Does it seem to occur at steady speed?

    2. Is the stuttering immediate after rolling on the accelerator, or at some somewhat predictable distance, if the rolling on is gentle and consistent?

    3. When the stuttering occurs, is it brief and clears up, or is it prolonged, or varies?

    4. When you machine heats up to the place where you expect the stuttering, do you feel a subtle surging when running at 2000 to 2500 rpm in 3rd? If no tach, that is just above what you might consider to be lugging.

    5. Is the stuttering worse after a prolonged stop, say, at a particularly long light?

    6. Once warmed up to where you expect the stuttering, do you detect erratic idle speed, and/or rough idle?

    6. Does it ever occur without having to first warm up? Even if rare.

    7. If the stuttering is ever prolonged, and you try to accelerate, does the engine note start breaking up and power go flat?

    Whatever else you can notice might be helpful?

    Enjoy,
    Rich P
     
  7. Aceboympk

    Aceboympk Member

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    Ribeye, these are great questions!

    Hopefully the OP is comfortable with my posting answers because on my ride today I began experiencing the same symptoms. By the end of my ride today, my bike barely made it home because it was constantly stuttering.

    I'd appreciate assistance so I'm more knowledgeable when I talk to the mechanic. I just bought this bike, so I'm not comfortable doing work myself. I'm likely to take the bike to a dealer b/c I don't know a Harley mechanic in my area, and the HD dealer here (Oak Park, IL) is pretty good.

    1. Does the stuttering tend to occur only when accelerating from stop or also from some fixed cruising speed? Does it seem to occur at steady speed?
    Answers: The stuttering occurs when accelerating from a stop and while cruising. Yes, it also occurs when at a steady speed.
    NOTE: Stuttering does not occur when I'm at idle. The bike starts without any stuttering problems. It idles without stuttering when I'm at a stop, even after it has been stuttering while cruising.

    2. Is the stuttering immediate after rolling on the accelerator, or at some somewhat predictable distance, if the rolling on is gentle and consistent?
    Answer: The stuttering is immediate after rolling on the accelerator when I'm at a stop, even if the rolling on is gentle and consistent. I've tried everything regarding rolling on the throttle (soft, gentle, consistent, aggressive) and the stuttering continued to get worse.
    NOTE: While at a cruising speed, when the stuttering initially began it seemed to go away by accelerating. Later in the same ride, the stuttering continued even with my attempt to accelerate, or gently and consistently.

    3. When the stuttering occurs, is it brief and clears up, or is it prolonged, or varies?
    Answer: The stuttering just began today during my ride. It would stutter and then stop for 10-15 minutes while cruising on the highway. Later, it was stuttering consistently. So the stuttering is now prolonged and varies in all gears, RPM rate, speeds, etc...


    4. When you machine heats up to the place where you expect the stuttering, do you feel a subtle surging when running at 2000 to 2500 rpm in 3rd? If no tach, that is just above what you might consider to be lugging.
    Answer: I don't have a tach on my bike, but the stuttering is consistent at all speeds, from stop to cruising and while cruising.


    5. Is the stuttering worse after a prolonged stop, say, at a particularly long light?
    Answer: the stuttering seemed to be the same at each stop whether that was a short stop or a prolonged stop. It is much worse from a complete stop versus a "rolling" stop when I would roll through a stop sign.


    6. Once warmed up to where you expect the stuttering, do you detect erratic idle speed, and/or rough idle?
    Answers: The bike stutters less while it is warming up, and is consistent after the bike is warmed up. While idling at a stop, the bike idles without issue. Only stutters when I begin to roll on the accelerator, then while cruising. The bike seems to stutter more after the bike is warmed up.

    7. Does it ever occur without having to first warm up? Even if rare.
    Answer: I let the bike warm up and it still stutters.

    8. If the stuttering is ever prolonged, and you try to accelerate, does the engine note start breaking up and power go flat?
    Answer: YES!!! Power goes dead flat like the bike is about to die and the engine note definitely starts breaking up.

    Whatever else you can notice might be helpful?
    NOTES:
    -This bike is fuel injected
    -Top end redone less than 1k miles ago (new 10:1 high compression pistons, cams, rings, and bored out .005 over)
    -Just over 37k miles on the bike
    -This bike is a '97 Road King
    -I just bought this bike. I've owned it for a few weeks. Today was the first time it stuttered. It started intermittently while on the highway, then became consistent.
    -The day I bought the bike, I drove the bike home on the highway, though I kept the speed around 60 mph. Today I was driving it around 80mph. I've been driving it around town, and no signs until today.
    -This bike does not have cruise control, but it has a screw that I can tighten the throttle. That screw fell out within the last two riding days.
    -The grips were changed recently before I purchased the bike.
    -I love this bike. It took me a long time to buy a Harley. I understand bike's need maintenance, and even if this bike requires more than my other prior owned bikes, I'll love riding this bike once I can get this problem fixed.
    -The only thing I changed since owning this bike is taking it to the dealer to put on new tires and brakes.
    -I only use premium fuel from quality gas stations.
    -The bike hasn't been ridden very much over the past 1-2 years before I bought it.
    -The bike was backfiring while it was stuttering today. About the same volume of backfiring as "usual"
    -The bike would backfire a little bit while decelerating during my previous rides, though I didn't think much about it. It is a *very* slight backfire and isn't consistent while decelerating.

    Thanks,
    Mark
     
  8. RibEye

    RibEye Junior Member Contributor

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    Unfortunately, your symptoms can be caused by a variety of problems. I would start with the 2 most likely ones:

    1. Low fuel rail pressure, likely caused by rub/pin holes in the fuel lines inside the tank. (Verified by fuel rail pressure test)
    2. Intermittent fuel injector lines (broken inside the insulation or at the connector pin, due to vibration and insufficient strain relief at the injector(s))

    Other causes are possible, but check the 2 primaries first. Others are:
    • Clogged fuel filter (varnish from old gas, or just old filter)
    • Clogged quick disconnect, where the fuel exits the tank.
    • Sticking injector(s) or fuel pressure regulator (again from varnish)
    • Intermittent fuel pump (bad supply line, connection at fuse block or ECM, etc.)
    • Bad throttle postion sensor or connections
    • Bad crank position sensor or connections
    • Others less likely (engine temp sensor, incoming air temp sensor, etc.))

    You could also have a bad coil, plug wire, or plug.

    Trust me. I have been where you are, and I found several items on the list...bike sat for aong periods before I bought it. All is well now, and what a great joy to finally be running consistently sweet. Check items one at a time. Don't go hog-wild. Slow and steady is the key.

    Good luck,
    Rich P

     
  9. pappy42

    pappy42 Member

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    Sounds like a fuel problem and you have recieved some excellent advice. I once bought a customized FXLR that the previous owner spared no expense in the build.

    Bottom line, as the bike warmed up; the ignition coil would develop a problem that maifested itself as a breaking up and (EDIT) out. The kicker was that it was not consistent in it's actions. Drove me nuts.


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    Last edited by a moderator: Aug 29, 2011
  10. Aceboympk

    Aceboympk Member

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    Rich P (aka RibEye),

    Thank you very much! I'm taking it to the dealership sometime today and I'll mention these areas to focus on. Your questions were incredibly helpful because I wouldn't have known how to articulate the symptoms without your questions.

    Regards,
    Mark