M/M EFI runaway idle when cold 3000 rpm
 

Now I've heard that the M/M fuel injection on my '97 FLHTCI has problems with high idle when its cold but this is getting ridiculous! I adjusted the cold idle speed as per the manual and it starts easy and idles up to 1150 rpm when cold then drops back down if I let the motor warm up good before moving. The problem comes when I start riding if its below 65 degrees out. If I go a mile or 2 at say 50 mph, when I come to a stop the idle is at 15-1600 rpm. If I sit at idle long enough (2 or 3 minutes) the idle comes back down. If I don't let it come down, the next light a mile or two down the road the idle will be 18-1900 rpm. This repeats until (if its cold enough, like in the 40s) my idle will ramp up to close to 3000 rpm. Sounds real cool when sitting at a light. Anytime though, if I let the motor heat up good at a stop eventually it ramps back down to 1000, maybe in 4 or 5 minutes of idling. Its weird, the idle slowly ramps up as I ride, I can check it by backing off the throttle and putting the clutch in while moving. It's really getting annoying.
BTW I've changed the ET sensor twice already and it still does it. The connector looks OK at the ET sensor and it fits tight, can find any damage to the wires. Once the temp outside goes above maybe 70-75 degrees it quits. So its gotta be ET or maybe IAT sensor or input. Or could I have a faulty ECM module? Any FI gurus out there seen this before? I don't have a breakout box.

Thanks, Bogey

Hey Bogey. Did you ever resolve this issue? I'm living with it now, and before I convert it to a carburated system thought I'd do my homework...... I know this is an old post, but I'm hopeful. Thanks in advance. CJ

Change the engine temp sensor.
Bob

This post is 6 years old and Bogey-52 has not been back for 5 years. The MM is almost like a carb with the stuff that screws up on a carb left off and much more control. Do some you tube on it. Once you understand it, you won't convert unless you just have a bunch of free stuff laying around.

see thread at https://www.hdforums.com/forum/ignit...away-idle.html for info on this problem.