Intermittent no spark issue

[cjnspecial 0]

2018 TRX500FA7. It will start and run fine for a few minutes, then it dies and won't restart for 30-40min. Tore into this afternoon and the signal wire for the coil isn't pulsing intermittently. There's 12v to the coil whenever the key is on, it's just the signal telling the coil when to fire that's crapping out. The prime suspects are now the ECU, loose wire or a crankshaft position sensor but I can't seem to find the CKP on the dealer parts diagrams. Is there one on this bike or is there something else sending a signal to the ECU? is there anything else that can cut signal to the coil? 
 

The tilt sensor is fine, it's full of oil and the run stop switch tested okay as well.

[shadetree 5,869]

10 hours ago, cjnspecial said:

2018 TRX500FA7. It will start and run fine for a few minutes, then it dies and won't restart for 30-40min. Tore into this afternoon and the signal wire for the coil isn't pulsing intermittently. There's 12v to the coil whenever the key is on, it's just the signal telling the coil when to fire that's crapping out. The prime suspects are now the ECU, loose wire or a crankshaft position sensor but I can't seem to find the CKP on the dealer parts diagrams. Is there one on this bike or is there something else sending a signal to the ECU? is there anything else that can cut signal to the coil? 
 

The tilt sensor is fine, it's full of oil and the run stop switch tested okay as well.

if you are calling the CKP the same as the pick up coil ?, i just looked your model/year/make up, i see honda in their wisdom decided to make the stator and pick up coil all one part ?!. and its not cheap...right at 500 bucks. you can find this info under the fich parts under generator, it is the stator that has the pick up coil.

[cjnspecial 0]

CKP= crankshaft position sensor. I was hoping it wasn't the ECU but that would be a cheaper and faster fix. It may just be some debris or contamination on the sensor...I'll dig into it and post the findings later this week. 

[cjnspecial 0]

A quick update: followed the dx procedure in the FSM and narrowed it down to the CKP(pickup coil). Replaced the stator assembly today and it's doing the same thing. A friend came over with an oscilloscope and the waveforms go away for the CKP go from perfect to non-existent with degradation, it just happens at once. Applying back voltage to the signal wire brings the waveforms back. He said the ECU is the most likely suspect, hopefully this fixes it. 

Edited December 31, 2023 by cjnspecial