Have an 05 ultra FI that has me stumped as well as 2 Harley mechanics. Initial start up will run great cold, but as soon as it gets hot it will start to cough and ocasionally die, running down the highway it does ok, but when I come to a stop or slow my rpm's the bike begins to cough and stumble. I have SE tips, SE Air intake, stage 1 download with a new fuel tuner added (thought that was the problem) also have new internal fuel tank line and external fuel line, new fuel filter, new intake seals, changed IAC,TPS, IAT sensors as well, made no change. I took the bike to Harley shop, they ran the diagnostic and came up with nothing, the bike died and coughed on them, they pulled up a IAT code and tried a new sensor,did not work either, had everyone stumped. Took it to another Harley technician that sprayed carb cleaner and hopefully found the problem being a injector, would run better by spraying it from left side of bike directly at injector while shielding the intake. Before I bought the bike I was told it had been sitting for 2 1/2 years and the injectors were pulled and soaked in carb cleaner for days. O-rings looked good on the injectors when pulled. Can the injectors be damaged by cleaning with carb cleaner and do the symptoms indicate a possible injector problem? I am becoming overwhelmed financially as well as the mechanics becoming fustrated not finding the problem. Mechanics have bent over backwards for me. The dealership did not even charge

 

Far from an expert, but if it ran better when sprayed from the left side wouldn't that point to a possible air leak? If it had sat for 2.5 years, I would think that there could be some shrinkage in the o-rings. Just a thought.

 

What stumps me is: shouldn't it do it constantly even when you first start it if the o-rings are bad? Runs great after first starting, great throttle response until it gets hot.

 

Just read a post on another forum that had a similar problem and it ended up being the manifold seals.

 

gotta agree there! when it warms up, The metals expand & it starts sucking air! Was one of the sensors that you replaced a temp sensor?
hatch.

 

My brother's bike would start up and run fine for 5 to 10 miles, depending on the temperature outside. Then the motor would simply cut out both while riding or when he came to a stop. If he let it really cool down, the bike might start and get him part way home. Again, die when it warmed up. Harley Dealer ran the diagnostics on it and couldn't figure it out. Left it with an Indy for several weeks and they couldn't figure it out.

He took it home and started working on it in the garage at night without all of the overhead lights on. When he turned on the ignition in the low light, he saw an electrical arc inside one of the sealed connectors of the OEM wiring harness. That was the culprit. Apparently, when the bike got hot, this weak link in the harness shorted out the ignition and the bike died.

My brother cut the bad connector and soldered a new one in and has never had a problem since. Go figure...if he hadn't had the lights turned down low, he never would have noticed the light coming from the arc inside the connector and he'd still be scratching his head!

Just wanted to pass this along incase you haven't considered the electrical harness.

Good luck.

 

All good possibilities...another to throw into the mix is that sometimes when coils are starting to fail they will do so only when warm.

My first step would be to determine if it was a fire or fuel issue.

Warm it up enough to start running crappy, then pull the plugs and see if you have a good strong spark. If so, then it is probably a fuel problem.

Kevin

 

The intake seals were replaced with no luck, never replaced the temperature sensor.

 

It looks like it is going to be something odd then. Fuel, spark, air are the three parameters as mentioned. If it were me, I think I would look at spark next to rule that out since it doesn't look like your troubleshooting has focused on that. I would check the spark at the plug and use the dark garage trick to look for shorts that may be arcing as have been mentioned.

I would think if you are having injector problems like low pressure or something that it would throw a code.

Have you closely inspected your coils? If they get hairline cracks, they can arc as well. When you look for arcing, also make sure to check them as well as wiring.

 

For now I told the mechanic not to order the injectors as I believe if it was the problem the bike would run constantly bad especialy down highway speed. I did continue the order for the o-rings. We will see how it goes from there.