I am trying to help my buddy sort out an issue on his bike vs. him taking it to a shop, paying a few hundred bucks, he gets it back "fixed" yet it still has the same issue.

Bike is an 08(I believe, im verifying) ultra classic. Its a 96 cu. in., I know that. I understand 08 was the first year of throttle by wire so I know it makes a difference when trying to trouble shoot.

Bike has a piggy back FP tuner on it...

The bike will cold start every time, no issue. Ride the bike and get it hot, stop, say for fuel, and the bike will crank no start. When it does this you can let it crank till the battery is dead. Let it set 5-10 minutes however and it will start right up.

The bike will run down the road for HOURS on end with no issue.

It does not seem to matter if the gas tank is full, half, 1/4, etc...

Today I rode it and was trying to trouble shoot it(I got it to act up). I unhooked the FP tuner and plugged directly into the ecu. Still crank no start. To me that eliminates the FP tuner being an issue. I was reading of issues with the older piggyback FP tuners doing stuff like this. Every time after I disconnected the ECU and plugged it back in, the bike would start, then immediately go to the no start. That points, a little bit, to an ECU issue... reset the computer and boom it will start, but then right back to crank no start.

He just got the bike back from having a starter put in it. In the past I believe all the hoses in the fuel tank were changed out as one of them was found to have a split in it, which again I read is a common issue. I dont believe the fuel pump has ever been changed.

IF this bike has a check engine light, i have never seen it illuminate. I believe codes can be pulled from the dash using some combo of button pushes.

I can hear the fuel pump prime, which obviously doesnt rule out the fuel pump, but typically a fuel pump that is going out or is dead will not prime. I do not know how to test fuel pressure on this bike, if thats even possible.

I have not tested spark in this crank no start condition.

I do not feel like I get a strong odor of gas when it does this like its flooding the bike.

To me it feels like a fuel issue, but the fact that I can disconnect the ECU, reconnect it and the bike will start, points to an ECU issue. I have read a few threads that read similar to this issue that say its the compensator, but MOST of those threads point towards lots of bad noises from the primary and the bike not wanting to even really turn over. This bike will crank HARD for as long as I want to hold the button.

Anybody got any clues on where to proceed vs. telling him to take it back to the mechanic?

 

Well the first thing I thought of was the fuel lines in the tank as thats what mine was doing, changed them out as there was a split in them and it fixed it, but since you said they were changed out, it's ruled out.......so.......
When doing the spark check, leave ONE plug connected in the cylinder and check the other one.......then reverse for the other one......reason being if you have BOTH plugs out and check it will show nothing,,,,,,,,the ECM has to see some spark and compression on one of them to fire the other.....It's got an ION sensing part of it that it has to see........

Good luck!!

 

You need to look at the basics first. It will help you if you have wiring diagrams for the bike. These are factory, color diagrams which should help? https://serviceinfo.harley-davidson....82bf6ed5a!!1!3

• You need to check for trouble codes
• As the starter was replaced that would indicate the battery cables were disconnected - go back and check them carefully, not just for tightness but overall condition
• As the fuel lines were replaced I would double check all of the connections in and round the fuel tank and throttle body
  • fuel injector plugs connected and tight
  • fuel line from tank to throttle body tight
• Check your plugs - tight
• Check plug wires at both spark pulg and coil ends

 

He has said they were changed out. He is not a mechanical person. I am TEMPTED to tell him to ride this tank out of fuel then we will pull the tank and pull the fuel pump assembly and check everything out. To me though, if it was a split or hole in a line, it would have issues all the time and not just when hot.

If the bike was throwing codes I "assume" it would be lighting the check engine light.

And the rest of your list I will check, but again, the bike starts cold every time, its only a hot start issue. If it were battery cables, fuel injector plugs, fuel lines, plugs, plug wires, etc... I would, again, assume, it would have issues all the time and not just when hot.

 

He has said they were changed out. He is not a mechanical person. I am TEMPTED to tell him to ride this tank out of fuel then we will pull the tank and pull the fuel pump assembly and check everything out. To me though, if it was a split or hole in a line, it would have issues all the time and not just when hot.

NOT necessarily........believe it or not there has been some strange occurrences that happen when they split...........with about a half a tank of fuel, turn on the ignition but dont start it.......keep the gas cap off and with a flashlight look in the tank........is fuel being sprayed everywhere? Could be a split or a loose hose.

 

I will do this test and see what I can see.

 

OR it could be the plastic fuel filter housing that sometimes cracks and gets the same results.......if they didn't really inspect it when they replaced the fuel filter and missed the crack, it will be doing the same thing......

 

I had hot starting issues so now when I start the bike when it is hot I do not let the fuel pump run. Turn on the switch and hit the starter button immediately it starts every time. Try it! Can't hurt. Sometimes it's the simple things.

 

^^^^^^^^^^^^that too!!!

 

Im thinking to pull the tank and the fuel pump assembly out and inspect everything. It dont cost nothing but some time. My buddy should be off work soon so I can pick his brain a little more on what was done when the lines were supposedly changed out before.

I read that also, but I would RATHER fix whats wrong than to bandaid it... I feel that having to do that means something is wrong with the bike.