No spark after replacing crank position sensor
#1
No spark after replacing crank position sensor
We bought an '07 Road Glide out of a salvage auction as a 'project bike' and my eyes are already crossing. I couldn't get spark to the rear cylinder. No error codes at all. Replaced the coil, plugs and plug wires (don't get me started on that decision) but no change. After I replaced the crank position sensor, I couldn't get a regular spark on the front cylinder anymore. It now only sparks a single time - when I RELEASE the start button. Verified the ECM/TSSM are good by swapping them on my '07 Ultra. Ultra still ran fine and the spark crap on the Road Glide didn't change.
I'm running out of ideas.
I'm running out of ideas.
#3
Well first thing to tell ya (so I heard) the ECM has to see compression for the plug to fire, testing the plug OUTSIDE of the engine and grounding it to the frame wont show spark as it doesn't sense the compression. (ION sensing ignition?)
Get an INLINE tester is I believe the way to go on that.
Are you getting fuel?
Get an INLINE tester is I believe the way to go on that.
Are you getting fuel?
#5
Well first thing to tell ya (so I heard) the ECM has to see compression for the plug to fire, testing the plug OUTSIDE of the engine and grounding it to the frame wont show spark as it doesn't sense the compression. (ION sensing ignition?)
Get an INLINE tester is I believe the way to go on that.
Are you getting fuel?
Get an INLINE tester is I believe the way to go on that.
Are you getting fuel?
No fuel because I took the tank off to change the coil. Didn't make any sense to put it back on till I had spark.
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HarleyTCL (08-07-2021)
#6
Didn't test the exact amount of compression but yes - felt for compression when I tested each side of the coil. Tested for spark visually by grounding the plug on the motor.
No fuel because I took the tank off to change the coil. Didn't make any sense to put it back on till I had spark.
No fuel because I took the tank off to change the coil. Didn't make any sense to put it back on till I had spark.
And checking compression with your finger in the hole doesn't count, the ECM has to SENSE compression through the plugs and plug wires.
#7
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#9
We bought an '07 Road Glide out of a salvage auction as a 'project bike' and my eyes are already crossing. I couldn't get spark to the rear cylinder. No error codes at all. Replaced the coil, plugs and plug wires (don't get me started on that decision) but no change. After I replaced the crank position sensor, I couldn't get a regular spark on the front cylinder anymore. It now only sparks a single time - when I RELEASE the start button. Verified the ECM/TSSM are good by swapping them on my '07 Ultra. Ultra still ran fine and the spark crap on the Road Glide didn't change.
I'm running out of ideas.
I'm running out of ideas.
If I am understanding you correctly, the spark condition changed after you replaced the crank position sensor.....? If true, obviously something you touched during the CPS replacement, caused the spark condition to change...
I would concentrate there first...
Maybe verify you have a good CPS, not often, but sometimes parts are bad right out of the box...
Then follow the CPS wires to see if there are any pinched/broken/bare spots along the CPS wire circuit.
Finally, I would inspect anyhting electrical you had to touch, bump, or move while removing the old & installing the new CPS...
I hate electrical problems, but I usually manage to suck it up and get through them... Be methodical and persistent... you'll find the issue...
Good luck with the diagnosis...
Last edited by hattitude; 06-21-2021 at 11:08 PM.
#10
If your machine is wired like my 08 road King, the CPS wire runs under and across the frame in the vicinity of the front engine mount. There is a plug there that gets oil soaked from sloppy oil filter changes. Try separating the plug, thoroughly clean both sides and reconnect. If that doesn't fix it, at least you are no worse off.
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duker1111 (06-22-2021)