2002 Johnson 50hp has no spark in top cylinder. Suggestions on what else to check?

[OttawaPhil]

Hello, I have a 2002 J50pl4st fuel injected 4 stroke.
Has about 650 hours on it.
Had new fuel filter, plugs, and oil changed 2 months ago.

Has no spark in the upper cylinder. Other two work fine.
I swapped the coils and spark plugs around to see if it was those and it is not, the problem stays in top cylinder.
I have traced the two wires from the top coil pack to the ECU. The gray one splices into gray one for other two cylinders. Tested zero ohms to the ECU harness. The orange wire tested zero ohms perfect back to the ECU harness also. The connectors on the ECU and pins, and on the coil look great.

Does this mean my ECU has failed? Or what can I check?

I thought maybe I should move to a new thread as the old one was convoluted with unrelated stuff from before. The most important thing now is in does not have spark on top cylinder. Why would it have spark on bottom two but not on the top one? Is that a failed ECU?

I also have a DVA adapter coming today for my voltmeter, but I doubt that will help.


Thanks for your help!

 

[OttawaPhil]

How do I check the "trigger" I think it's called? Or anything else?

New ECU is $1370 so dont think it's worth throwing that much at it for a maybe it might work...

 

[racerone]

Hurry to a dealer that can run the ecu through a test..-----Evinrude or Suzuki.

 

[OttawaPhil]

I would like to check the "trigger" before I try going to a stealer.
I need to figure out what causes the ecu to send the signal to the coil. It must have three pickups one for each cylinder on the flywheel somehow. With a plate or something you can rotate to adjust timing. I'm thinking it might be that, but dont know how to check it.

 

[jakedaawg]

I posted it in the other thread...