My 07 Dyna Super Glide, with only approx 3,500 miles on it, has a major issue with the rear cylinder misfiring/dropping off. Check engine light started coming on after a few miles but no apparent issues. After a few more rides the check engine light starting coming on sooner and more frequent. At that point I stopped and had Harley check the code, which they advised was reading "ignition issue" but I would have to schedule and appointment for a more thorough diagnostic etc. With no noticeable issues other than the light coming on I decided to ride on and schedule another time.

A few days later I was riding, and after warm up within 5 miles or so, the rear cylinder went dead. I limped her home then after about a mile or so the cylinder picked back up and ran fine. I made and appointment with HD and dropped it off explaining to them the issues, "which started not long after a tank lift and billet headlight install". They called the next day and said ready for pick up, $81. I thought too easy and asked what was performed and they stated that they replaced the spark plugs, which obviously I could have done if I had thought it was that. I paid, loaded her up, and headed home. As soon as I got home and got it off the lift I rode about 5 miles, ran fine, then the cylinder went dead again! Now it drops off after about 2 seconds of starting instead of after warm up.



"UPDATE" I'm 99.9% sure it's the ECM. Fortunately Ive got a buddy who has an 06 Street Bob that's let me try his parts to trouble shoot. We've tried fuel injectors, ignition coil, spark plugs & wires, and metered all the wiring, including ground wires to the ECM, which all check out good. So it looks like I'm going to eat it and have to go with a new ECM. I'm going to have to find out if they can program a new ECM without having to take the bike to the dealership and they charge me labor for changing the old one out, which is already off the bike. Any suggestions or advice would greatly appreciated.

 

At this point, I would take it back to the dealer and tell them you paid to have it fixed and it's not. At least they can tell you what the problem is (hopefully) for free.

I really doubt it's your ECM. Are you the original owner? Is there a tuner on the bike?

 

Thanks Rooti, I have no choice at this point but to take it back to the dealer and see how much they break off in me. I'm the only owner, bought it new, approx 3500 miles on it.

 

If I am not mistaken, the EPA requires the ECM warranted for 5 years (this was the case in 2007 on my wife's Heritage). However, it is going to be a situation where the dealer will have to trouble-shoot and agree that is the issue and then fix it.

I also would agree that the issue is not likely the ECM. I would lean more towards a wiring issue into the ECM or around where you had work done (in addition to the other things you checked) before thinking the ECM was the issue. Also depending on the symptoms when it goes dead you may have a problem with your crank position sensor. I have had issues with my old 07 SG where the bike would drop rpms and barely run - turn it off, wait a few minutes, fire it up and runs ok for a while.

 

Thanks for the input guys, I really appreciate it. I will look over things again before I break down and head back to the dealership.

 

Put your ECM and TSM into your buddy's bike and see if the problem happens in his bike then you can be sure it is the ECM.
If it all runs fine then you know you still have to do more detective work.