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P.J., Technician
Category: Motorcycle
Satisfied Customers: 750
Experience:  10 years as a mechanic and fabricator in a privately owned, local, custom bike shop.
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My throttle position sensor was bad replaced it. Then took

Customer Question

My throttle position sensor was bad replaced it. Then took and did a leak test. Replaced the Map sensor gasket, and the intake gaskets. No more leaks can be found. Did a fuel pressure test. All good. No other codes came up. Cleaned all grounds wires and battery. Charging at 13.4. The bike runs at idle at 1600 and won't go down. IAC says 0-3%. And when riding it acts like you drop a cylinder.
Submitted: 2 years ago.
Category: Motorcycle
Expert:  P.J. replied 2 years ago.
Hi, my name is ***** ***** I'll be working with you today.
It sounds like a difficult problem and that you've covered most of the common occurrences. I'll share a few other things I've come across over the years causing similar issues and that you may want to check.
First thing is to remove any type of tuner you may have, other than a ThunderMax, of course.
Can you idle it down by covering the IAC hole with your finger? If not, there is a leak still existing somewhere. It may be in internal manifold leak. Idle should be 100% controlled by the IAC. There should be no other air available and the engine should quit when the IAC hole is covered. Very commonly overlooked is a broken throttle plate shaft. Also a bent throttle plate, or one with an obstruction or buildup causing it to remain slightly open, will also cause high idle issues. I'd eliminate all these possibilities.
I would also verify the sensor feed voltage is no more than 5 volt to any sensor. I'd quickly check this just to eliminate it but typically it does set a trouble code if a certain voltage threshold is surpassed.
The misfire could be clogged injector tips or injectors are coated in oil mist residue buildup causing the injector spray to not be atomized correctly. The residue issue is easy to find and fix, the clogging is not that easy to determine. I'd pull them and look at them. These misfires will not set a misfire trouble code.
I hope this helps. Please let me know if I can be of further assistance.
Thanks, P.J.
Customer: replied 2 years ago.
Thank you. We may have a short to the map. The breakout box's is saying so. But you gave me great ideas
Expert:  P.J. replied 2 years ago.
You're welcome. Best of luck. P.J.