My 07 Dyna Super Glide 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 coil?" 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.

At this point I'm so pissed off at the HD dealership since I spent $81 for nothing! Since I find them incompetent and don't particularly like giving them money for nothing I decided to try and trouble shoot on my own before I take it to a different dealership. I began by checking the plugs (even though they are new thought maybe plug wires) which appear to be getting good spark, so I assumed the rear injector may be going bad since it's getting spark, even though bike has low miles with approx 3500 miles on it. The voltage was reading virtually the same in both injectors, but I decided to try another injector in the rear to rule it out. After replacing the rear injector with an alternate injector, which was reading the same voltage, I'm having the same issue with no change or fix.

I'm running out of options so I thought maybe I had pulled something loose during the tank lift and billet headlight installation, since it all started shortly thereafter, but I can't find anything loose. Since it appears to be getting spark and fuel could the ingnition module cause this issue without affecting any other systems? Any help would ge greatly appreciated.

 

You had your answer at the very beginning.

It throw a code that it was the ignition coil.

You can get a new coil for somewhere around $50....but before you do that, make sure the plug from the ECM going to the coil is clean and seated well. If that does not solve it...get a coil.

What you describe sounds like a coil going bad, the code says it is a coil.

 

This sounds really dumb but I had a similar issue, threw the same code....ended up being a plug wire making intermittent contact at the coil end. Somehow managed to back itself off "just enough". Stupid and frustrating but a really easy fix....unplug and replug, clear code and here I am ~25k miles later good to go. I chased my tail on that one for a while thinking the sky was falling....felt like a complete idiot when my buddy figured it out.

 

I appreciate the help guys. Hopefully I can get this issue figured out before I have to take it back to HD. I got some input from another forum that suggested that it could be the temperature sensor malfunction on the rear sensor or a wiring issue that had been noted on some of the Dyna's, although I haven't rulled out the spark plug wires or the ignition coil module yet. I've switched spark plugs, as well as wires with the front cylinder and it fired fine. This generally would make me think that the ignition coil and plugs/wires should be good although the code stated ignition module/coil. Mayge the code is a general code and I'm actually having the temp sensor or injector wire issue. Either way I really appreciate all they help from you guys, it's narrowing things down. Again thanks guys.