When cold my bike runs well. Once it warms up it tends to stall but will run if I keep the rpm's up but then the rpms dance dramatically up and down while stopped at a red light. It runs steady only under a load at 2500 to 3000 rpm. I have replaced the fuel filter, fuel regulator, engine temperature sensor, idle air control and have checked the intake manifold seals with no success. Any suggestions? There are no error codes. I am discussing a 2003 H.D. Ultra with fuel injection.
Thanks,
Wally Graves

 

What bike are you working on?

Paul

 

Paul, the bike I am discussing is a 2003 H.D. Ultra with fuel injection.
W. Graves

 

How did you check for DTC codes?

On the 2003, I believe the codes you see in the speedo are normal and only for the speedo info. You'll have to get hooked up to a diag tool to get the rest of the codes. When you turn on the bike (no start) and the eng light will come on and then go out, if it blinks after that, it has a stored code. If it goes off and stays off then there are no stored codes.

When you replace the fuel filter, did you plastic fuel line in the gas tank for holes or cracks? You can check for that by opening the fuel cap and turn on the ignition switch (not started) and listen for fuel spraying or sloshing around in the tank. If necessary use a flash light to look in the tank for spary or sigins of leaking. The fuel pump shuts off after a couple of seconds, so you may need to cycle the ignition switch a couple of times to see what is going on.

Paul

 

Sounds like an IAC cleaning is in order. = idle air controller.

 

actually we replaced it, but thank you.
Wally

 

Paul
My friend has a diag tool but he said there were no stored codes. When I turn it on the engine light does not flash. We replaced the fuel line a few years ago but will check as you have advised. After reading all of the comments regarding the head temp sensor I am going to look at that again. We replaced it but it would not be the first time that a new part failed. I don't know where he got the part and whether or not it was good quality OEM parts.

Thanks for your help. This forum has given me lots to think about and I will get back to you but for now my bike is in storage for a few weeks.

Wally

 

Paul is right about dumping codes through the speedo.... All you'll get is speedo codes. There are ways to dump code but if the enging light does not come on a second time at key / run trun on, there isn't any codes in the ECM.

The issues to look at are the speed sensor and manifold leaks since you've replaced the IAC. IMO fuel pressure is not an issue.. I would guess that bad fuel is a possibility tho.

 

Just wondering , when you installed the new iac , did you recalibrate it before starting ? Not sure if your symptoms would be the case though .

 

I thought that the IAC is self calibrating.. At key on, it bottoms out the pintle then backs up to known setting. I would think that it would only be off by a step or 3 at that point which would be easily corrected.