Does anyone have any good trouble shooting procedures for Engine Code: P1356 ("Rear cylinder no combustion")?

Thank you for the help.

 

How is it running? I'm guessing normally; i.e., no miss.

Make sure spark plug wire is seated on the spark plug well. It's possible for the plug wire to be on enough to fire the plug, but not well enough to send the proper resistance back to the ECM.

If that fails, replace the spark plug with an OEM plug.

I don't want to thumb type on this stupid iPad all the details of how the Harley ECM senses spark knock through the spark plug. Suffice it to say they do.

Usually some simple thing triggers that code.

 

I had the same problem with my 07 sg loose plug wire was problem

 

It is running very poorly. Missing with much power loss. Most likely running on only one cylinder. I have replace the plugs with two new H-D Plug No. 6R12. The plugs in the bike were also H-D 6R12. The new plugs did not correct the problem.

I also have new H-D plug wires to install, but it looks like I need to remove the tank to do that. I can see were they plug into the coil, but seem to be routed up high under the tank, maybe with some wire hold downs.

Do you think I can replace the plug wires without removing the tank?

Thanks for the help.

 

That changes everything I wrote. Sounds like there REALLY is no combustion on the back cylinder. Not just a false code.

All internal combustion engines need air, fuel, and spark to run (and at the right time). Check for spark first. Easiest.

 

The plug wires on my 07 FLHR were held by plastic clips that snap onto little studs that are attached to the tank. Raising the tank an inch or more might help, along with some long reach needle nose pliers...

 

I check for spark and found spark at the front cylinder. No spark at the rear cylinder. I just got done lifting the fuel tank and replaced both front and rear spark plug wires. I started it up and it is still running bad, and front cylinder only.

Would the coil be the next thing to change?
Do power commanders go bad after a while? I had the impression they may.

The previous owner had installed a P/C. Is there a way to disconnect it for troubleshooting purposes?

Thank you for the help.