Fuel Injection / heat problem on 2001 FLHTCUI - Harley Forum

admin · #1 05-24-2007, 05:01 PM

I have a 2001 FLHTCUI that I think is having a heat related problem. It is the last year of the Magneti-Marelli fuel-injection system. It has the HD 95 big bore stage 1 kit, two into one Thunderheaders, and the fuel-inj is tuned with a Technoresearch process. It has approximately 53000 miles on it. The fuel mappings have been dynoed, and are spot on. The bike runs great when cold, but when it is hot outside, and the bike is warm, it acts like it has vapor lock. It stumbles badly in the 2700-2900 RPM range when gently accelerating, but normally can maintain a constant 60+ MPH just fine. The dealer has checked the injectors, sensors, and fuel pressure. The fuel filter was replaced a few years ago. Any suggestions would be appreciated!

Posted by: hdfxrsconv on Jun 26, 06 5:10:03 pm

admin · #2 05-24-2007, 05:01 PM

I would check the throttle position sensor.I've had this happen to injected car motors,dead spot, and have found the sensor to be shorted out at certain rpm's.By always running at the 2700-2900 rpm the electrical contacts wear out at that point,but just above or below that speed it's ok it could be the sensor.Check it with a meter by putting the test leads on the sensor pins and slowly rotate the throttle while watching the meter for a dip/loss of signal

Posted by: ULTRA on Jun 28, 06 10:44:03 pm

dallon · #3 11-08-2007, 10:53 AM

did you adjust the air/fuel mix screws on your mm before all else if not you will never get it right.mm has two sealed screws locatedtop center.adjust same as carb nobody seems to know about this.i run my 97rdking modified pipes and free breather i threw the dfo away after setting feul mix proper with said screws. it no longer sounds like a honda but sounds and runs like a harley should