check engine code quandry
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Stage IV
Joined: Feb 2008
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check engine code quandry
Just had to replace throttle body from Texas trip. Now when riding above 60 mph bike throws code that front cylinder is not firing. Ride is 2003 100th Anniversary Electra Glide Classic with no engine modifications and no other problems. Bike runs great above 75 and smooth. Anyone have past experience with this problem. Bike has about 75 thousand miles and is a keeper. One mechanic mentioned black tape over dash lite. Changed plugs and checked cables. Runs great in town and around the city under 62 mph. Any help appreciated trying to avoid local dealer since friend had rear lite fixed for just $711.00
Outstanding HDF Member
Joined: Apr 2010
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Who replaced the TB for you? Take it back and explain the situation and ask them to rectify the situation. Problem solved.
Can't believe 32 people read this and no one mentioned the above at minimum. Gotta love it.
Can't believe 32 people read this and no one mentioned the above at minimum. Gotta love it.
Stellar HDF Member
Joined: Feb 2010
Posts: 3,394
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From: Southern California
The misfire doesn't have to be enough so that you could feel it. The OBDII Code requirements are that if a misfire could cause the engine to eventually exceed 150% of the emissions standards, they have to turn the light on. Also if the misfire would be enough to damage the catalyst (if equipped).
The way the ECM detects a misfire is that it watches the crankshaft as it accelerates on each power stroke and then slows down until the next power stroke when it accelerates again. (Crankshaft Position Sensor) This may be hard to visualize, but the crankshaft is actually accelerating and decelerating continuously as the two cylinders go through the four strokes (Suck, Squeeze, Bang and Blow). If the crankshaft doesn't accelrate (or doesn't accelerate enough) on the power stroke for a cylinder. And it does this enough times, it'll set the code. We're talking in the neighborhood of 10 misfires for every 1,000 power strokes which is why you can't feel it.
Even though YOU can't feel the misfire, you definitely want to get whatever is causing it fixed. If it happened right after the Manifold replacement there could be any number of plumbing (vacuum leak?) problems or electrical wiring issues; that are, or could have happened in the service process. As BBStacker suggested, taking it back to the folks who did the manifold is a really good place to start. They would probably prefer to have a shot at it before you take it somewhere else; and then come back to them with a bill and the evidence that it was their work that caused the problem.
The way the ECM detects a misfire is that it watches the crankshaft as it accelerates on each power stroke and then slows down until the next power stroke when it accelerates again. (Crankshaft Position Sensor) This may be hard to visualize, but the crankshaft is actually accelerating and decelerating continuously as the two cylinders go through the four strokes (Suck, Squeeze, Bang and Blow). If the crankshaft doesn't accelrate (or doesn't accelerate enough) on the power stroke for a cylinder. And it does this enough times, it'll set the code. We're talking in the neighborhood of 10 misfires for every 1,000 power strokes which is why you can't feel it.
Even though YOU can't feel the misfire, you definitely want to get whatever is causing it fixed. If it happened right after the Manifold replacement there could be any number of plumbing (vacuum leak?) problems or electrical wiring issues; that are, or could have happened in the service process. As BBStacker suggested, taking it back to the folks who did the manifold is a really good place to start. They would probably prefer to have a shot at it before you take it somewhere else; and then come back to them with a bill and the evidence that it was their work that caused the problem.
Last edited by Bluehighways; Mar 25, 2011 at 12:31 AM.
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