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Back Cylinder Not Firing !

P

PaulMX

Member
06 FXSTBI 60k miles. Bike is 95". plugs are good, wires are good, coil is good. Whats my next step? Help, this bike is getting frustrated with me.
 
Sounds like the fuel injector is not firing. I would remove the power commander just to see if it now fires on both.
 
Sorry, I didn't explain my problem well/ there is no fire coming out of the coil for the back cylinder. I changed out the coil with one off another bike, it does the same thing, no fire for the back cylinder.
 
The spark firing all starts with the crank sensor. It could be a marginal crank sensor. It is possible that the sensor is able to pick up the "Big gap" for the #1 cylinder but can not actually count the number of teeth on the flywheel to fire the 2nd cylinder.
I would also do a Plug & Reseat of the ECM connector in case 1 coil trigger wire is not making good contact.

Will the bike run off just the 1 cylinder. If so, can you smell the raw fuel (if any) coming out of the dead cylinder. I am trying to determine if the fuel is being injected even though you have no spark.

If you are getting fuel injection, but no spark, I would guess your Crank sensor has to be good. The ECM would not be able to time the injector without it.
 
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First, what was the LAST thing done to the engine/bike BEFORE this problem developed? This may redirect everyone's thinking on potential problem-solving actions.

Chopper, any insights?

I agree with the suggestion above to remove the PC and see if the engine runs both cylinders with the original MAP, or any download that was done. This will help identify if you have a PC problem, or otherwise. If it still does NOT run, try replacing the CPS. And trace the coil trigger wires to make sure they are OK.

Let us know.

TQ
 
I think Hoople was right on, the first thing I would do is unplug the pc and plug the ECM in direct just to see, because pc is a go between, if it still does not fire it rules it out. Another common problem I[ve seen when only one cylinder fires is a break in one of the injector wires close to the plug, you can not see it because the plastic coating is in tack, it's easy to check with a wiggle test, but you said it's electrical so forget that, what trouble codes are present? I would check the trouble codes with the pc unpluged.
 
Took the pc off and and hook EMC direct both cyl fire, what yall think?

The bike is still on the table. But both cyl are firing.
 
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