Rear Cyl Misfire

[Loonytunes]

Hey all, I've got a 2013 street glide w/103. Supposedly cammed, pipes and tuned. Must have been a flash tune because original ecm is in the bike. I have a constant misfire in rear cyl. It's not steady but is always there. Idle, steady throttle, accel, pops and spits. Swapped plugs, known good coil and wires, no go. Compression test showed no sign of an issue, pulled the head anyway. Valves, rockers, gaskets all looked good. New gaskets on everything coming out. No codes, I'm leaning toward injector or ecm issue. I've read that tuners can be a problem but if it's a flash tune, would it be likely the ecm is at fault?

Missing out on some good riding weather because I cant figure this out. Anyone have any ideas? Hopefully I can provide enough information to point me in the right direction.

Any help is appreciated.

 

[Frenchie]

Check your rear cylinder exhaust flange mounting nuts, we’re they loose when you were in process off removing heads. Also check the cylinder head exhaust gasket . You might also have a leaking rear cylinder injector. If you are not throwing a code that means that the injector coil voltage is good but the injector could have some debris in in not allowing the injector to stop fuel flow. If you have an injector tester you would be able to reverse flow it and then in regular flow check you would be able to check the spray pattern.

 

[Loonytunes]

Thx for the reply Frenchie.

Exhaust nuts were tight going in. I checked intake and exhaust as first steps in the diag. Rechecked after re reinstalling. Good both ways, new gaskets coming out. I dont have an injector tester which is one of the reasons it's my last stone to turn. Quick search indicates they dont cost too much. Any preference on particular brand or specs on the tester?

 

[Frenchie]

I have the motion pro fuel injector tester at my shop but it is not cheap costs around $180.00. If you are going to test the injectors check on YouTube for some home made injector tester set ups. If you are going to replace the injectors I would recommend the fueling injectors that are available at DennisKirk or J&P cycles. Caution though J&P does a shitty job on backing items for shipment. Hope this helps. Let forum know what you find as your final result.

 

[Frenchie]

Attached is photo of injector tester I have at shop

 

[Loonytunes]

Thanks for the info. I will post a repair when I get it running.