05 Road King custom EFI cursed abomination
#11
07-25-2024, 07:33 PM
Do you have a Tuner on the bike? I had an issue a few years ago where my bike wouldn't start. I have a older Dynajet USB tuner on the bike. Turns out that even if the bike turns over if the tuner doesn't see enough voltage it will not fire spark. In my case I changed the battery, issue solved
#13
07-25-2024, 07:35 PM
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MotorSeven (07-26-2024)
#14
07-25-2024, 07:37 PM
I am gonna go out on a limb and say check your voltage drop on battery when cranking your bike, if it drops below 9.5 or so your ignition likely won't fire the plugs. I had a bike that the charging system was bad or very weak and would run but would not spark when cranking, only kick start. Non Harley. And I thought the plugs had to be in also, does not the bike sense compression to fire the plugs as well? First idea is a longshot, second one I am going off old grey matter.
#15
07-25-2024, 07:42 PM
Seasoned HDF Member
#16
07-25-2024, 09:36 PM
fuel pump yes, it runs when you first turn on the ign , rear cylinder does have compression
#17
07-25-2024, 09:40 PM
Seasoned HDF Member
#18
07-25-2024, 10:11 PM
Here's a good one... does the bike happen to have a piggyback tuner installed?
I ask because I had the same issue and after replacing the coil, plugs, & wires, it still had no rear spark... until I decided to pull the DynaJet PCIII tuner off and try without it.
It fired and ran quite well, though plenty lean w/o the tuner adjusting the AFR.
Just a thought, if you have a tuner, pull it and see if you get spark in stock configuration.
I ask because I had the same issue and after replacing the coil, plugs, & wires, it still had no rear spark... until I decided to pull the DynaJet PCIII tuner off and try without it.
It fired and ran quite well, though plenty lean w/o the tuner adjusting the AFR.
Just a thought, if you have a tuner, pull it and see if you get spark in stock configuration.
#19
07-25-2024, 10:12 PM
Take a wire and ground the plug wire to a ground. THAT is what is meant by grounding a plug wire. Taking a spark plug and grounding THAT will cause th ECM to see the engine as in a cannnot fire condition.
The ECM SEES how a plug fires anymore. This ain't your fathers Oldsmobile. The ION sensing circuit can tell if the plug is trying to fire under cylinder pressure or not. No such thing as an 'ignition' on a bike with an ECM. If it has EFI and its newer type bike with Delphi ECM, ground the plug. THIS will in turn tell the ECM that you are working on the bike and will NOT even try to fire the injectors, plugs, etc. Before the engine even finds its compression stroke, it will 'see' the ground. A newer bike will not KNOW which stroke is combustion and which is exhaust. Everytime one hits the starter, the bike has to find that out using the crank sensor and software. Grounding turns THAT system 'off'.
I am looking to confirm or deny the accuracy of that statement in regards to my bike.
#20
07-25-2024, 10:20 PM
Seasoned HDF Member
not sure i will check in the morning, thanks for the assist, i did find the following:
Take a wire and ground the plug wire to a ground. THAT is what is meant by grounding a plug wire. Taking a spark plug and grounding THAT will cause th ECM to see the engine as in a cannnot fire condition.
The ECM SEES how a plug fires anymore. This ain't your fathers Oldsmobile. The ION sensing circuit can tell if the plug is trying to fire under cylinder pressure or not. No such thing as an 'ignition' on a bike with an ECM. If it has EFI and its newer type bike with Delphi ECM, ground the plug. THIS will in turn tell the ECM that you are working on the bike and will NOT even try to fire the injectors, plugs, etc. Before the engine even finds its compression stroke, it will 'see' the ground. A newer bike will not KNOW which stroke is combustion and which is exhaust. Everytime one hits the starter, the bike has to find that out using the crank sensor and software. Grounding turns THAT system 'off'.
I am looking to confirm or deny the accuracy of that statement in regards to my bike.
Take a wire and ground the plug wire to a ground. THAT is what is meant by grounding a plug wire. Taking a spark plug and grounding THAT will cause th ECM to see the engine as in a cannnot fire condition.
The ECM SEES how a plug fires anymore. This ain't your fathers Oldsmobile. The ION sensing circuit can tell if the plug is trying to fire under cylinder pressure or not. No such thing as an 'ignition' on a bike with an ECM. If it has EFI and its newer type bike with Delphi ECM, ground the plug. THIS will in turn tell the ECM that you are working on the bike and will NOT even try to fire the injectors, plugs, etc. Before the engine even finds its compression stroke, it will 'see' the ground. A newer bike will not KNOW which stroke is combustion and which is exhaust. Everytime one hits the starter, the bike has to find that out using the crank sensor and software. Grounding turns THAT system 'off'.
I am looking to confirm or deny the accuracy of that statement in regards to my bike.