FI Problem?

Discussion in 'Other Service and Maintenance' started by ProF, Jul 3, 2008.

  1. ProF

    ProF Junior Member

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    Here's a strange thing that hasn't happened before.

    Last evening I took the bike out (03 RG FI), and it started up but sputtered and coughed for several blocks, just like my old carbed bike would do if I forgot to turn on the gas. Finally it died and wouldn't start. Thinking it was gas, I opened the gas cap a bit and heard a rush of air into it, and tried again. It started right up and ran the rest of the evening with no problems at all. So I thought it was the gas cap on too tight and bad venting.

    Today, the same thing happened, so I loosened the gas cap while riding. The problem didn't go away, but the bike didn't die. After about a mile, and after I screwed the cap on again, it settled down and has been fine since, even after turning it off long enough to get a haircut. When I came out and started it up, everything was fine.

    I've had the bike for 4+months now and it's never done this before.

    The bike is garaged, so it wasn't too hot or too cold when this problem began.

    Any ideas?
     
  2. glider

    glider Veteran Member

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  3. ProF

    ProF Junior Member

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    Glider, I read the article on the holes in the gas tank hose, but the second time the problem occurred, I'd just filled the tank. The tank was full almost to the spout.

    Today I fooled around with the cap...it doesn't seem to be blocked. Then I unscrewed the cap and started the bike. It started up fine and seemed to idle ok, even when I raced it a bit. Cracking the throttle didn't cause a stall or even a miss. Thought it was fine, so got on and drove down the street. Missing, popping, coughing all the way around the block! Got back to the garage and turned it on and off trying to hear any difference in the fuel pump startup. I did notice that turning the key on, off, and then on again with only a few seconds in between, the fuel pump didn't seem to cycle fully. Normal?

    Took the bike out and around the block again...everything perfect! No hesitation at all.

    Wouldn't a hole in the pressurized fuel line cause the problem to continue, at least until the level of the gas rose in the tank? Would it allow for the bike to run normally after about 5 minutes? All very confusing.

    Ideas? You mentioned in another post that the temp sensor could be a problem. Here, too?
     
  4. glider

    glider Veteran Member

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    The hole in the line causes a loss of fuel pressure regardless of the fuel level in the tank which in turn causes poor running when this happens.
    The short cycle of the pump you mention could be because there was residual pressure still in the system from the first start seconds before.
    The first post you mentioned that the cap off made a difference, that's why I thought a bad vent in the cap.

    Your problem sounds as if it could be a crank sensor going bad or possibly another sensor.You may have to check the sensor out to see if it is loosing the signal with a meter.

    Crank Sensor (CKP) - Harley Davidson Community

    Have you checked for codes and is the light lit in the speedo?
     
  5. ProF

    ProF Junior Member

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    Thanks for the input. I'll test out the sensor tomorrow. I don't get why it seems to "cure" itself after running for a few minutes. Harleys don't "cure" themelves! I'm also going to check out my Revtech DFO, just to make sure that no wires are loose. It's currently set at Green 4; Yellow 6; Red 4; RPM Switch 4.

    There have been no codes, and the checklight goes out as soon as the pump finishes cycling, just as always.

    I'm pretty sure that the venting issue with the cap was purely coincidental, as running it today with the cap off made no difference. Off or on, it runs badly for, tops, 5 minutes, and then is good.

    I'll post the results of the sensor test.

    Thanks.
     
  6. glider

    glider Veteran Member

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    Some electronics as well as wiring problems are effected by heat and that could be a contributing factor with this problem. If your DFO isn't the type with the integral harness, check the connections to see if they are OK especially where the line plug is. The pins have a habit of backing out of the plug on the older models..
     
  7. ProF

    ProF Junior Member

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    Yesterday I attempted to check the crank sensor, following the instructions that Glider posted, and got as far as trying to pull the sensor socket out of the little cubby behind the ecm that it sits in. I couldn't get it out far enough to separate the plug from the socket, and was afraid to pull too hard and break a wire somewhere.
    I then went back to the gas cap issue, and removed the internal spring and valve in the cap, leaving an open vent.
    Putting everything back together, I took it for a short ride. All was well, and I thought maybe, just maybe, it was the cap after all.
    This morning, I started it up, and it ran perfectly for about 3 blocks. Then it started the sputtering, but only at low rpms. Once the bike got moving, it smoothed out. This went on for about 2 or three block, then all was perfect for a while. I stopped for a yard sale, and the bike started up again and rode perfectly home (about 10 blocks) until just as I turned into my street, it coughed and died. I waited a few seconds, restarted it with no problems, and it went the rest of the way home perfectly.
    I live on a hill, so when I turn onto my street, I've already downshifted into 2nd, sometimes 1st if going really slow.

    I read a few posts on another forum that had similar problems, and the comments there suggested that the crank sensor either works or doesn't. I thought maybe a loose connection on the sensor plug, but when I wiggled all the wires, nothing jumped out at me. Having been plagued by wires broken inside the insulation on my old bike, I always wonder about that problem.

    Guess it's time to run it in to the indy and see what he says. It just bugs me that I've only had it 5 months and already there's a problem. It's 5 years old, but very well cared for, so I wasn't expecting this. Bummer.
     
  8. Bud White

    Bud White Well-Known Member Retired Moderators

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    I cant say on harleys but i have seen in automotive where the crank sensor will be hit or miss usually it takes a cool down before it will work again ..
     
  9. wildspirit97

    wildspirit97 Senior Member

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    did you check all the connections on the injectors and your DFO as Glider suggested...I think he may be on to something there. Maybe even unhook the DFO and go for a ride it will be a little lean but it will tell you if that's the problem or not. And if you have the stock air cleaner Just put it back on if you to want it to be too lean.
     
  10. ProF

    ProF Junior Member

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    One last question before I head out to the dealer:

    I called my indy and when I described the problem, he immediately thought of the in-tank hose and told me to take it to the dealer who would put it on the analyzer and take care of the problem for around a hundred and a half. He said that he didn't have the analyzer they had and he'd have to try a bunch of things which the dealer could rule out or in in an instant.

    Now the question: (I'm really long winded, aren't I?)

    I tried the test Glider described, pulling the fuel pump fuse and trying to start the bike, and the bike started fine. I replaced the fuse, started it again to pump up the pressure, and took out the fuse again. This time I let the bike sit for several minutes to give the pressure time to escape from a slow leak, and it still started right up. Does that mean that there is definitely no leak?

    Riding the bike yesterday, I found that the problem persisted from startup until around 10 blocks or so, or until it was somewhat warmed up. Then, no further problem, either in town or on the freeway. The bike then sat for a few hours, and I took it out again, this time at night. Same thing. Went about 2 miles with it sputtering in the low rpms, and then fine on the freeway for the rest of my ride home, about 20 miles.

    Any new thoughts, or am I doomed to visit the Stealer>

    Thanks. I won't bother you guys again (with this problem, anyway).