95 200 Pro Max ecu issues with no start

[Reezenbowhunter]

Looking for some help on my 95 Pro Max 200 EFI. Serial number unknown, tag rubbed off ink stamp and not anywhere on block or Welch plugs. Recently had an issue with stator and has since been fixed by replacing stator, switch boxes, trigger and voltage regs. Motor blew a few yrs back and the guy was nice enough to install an oil drive gear after oil injection was removed and one of the crank gear screws came loose and played pinball inside and you can figure out the rest. So now to rebuild #2, first rebuild had less than 100 hrs and now this one is still in break in time and it quit running going across lake and would not start again. Has fuel, fire, but seems to not fire fuel injectors. Will start on a spray of carb spray but obviously stalls right away. Had someone give me a regular 200 EFI non Pro Max ecu that started boat after messing with a few things like checking spark and plugs. Once it fires I tried old ecu again and nothing, plugged loaner ecu back in and nothing again. So my question is could there be something that is sending a short to ecu causing it to burn up or fail? Old ecu smells burnt at cannon plug so pretty safe to say it's cooked. I'm concerned with loaner box for something causing a back feed and shorting it out if possible. Any ideas or things to check that I have not already? Sorry for long post but I know the BBC community can help.

[Reezenbowhunter]

Anybody? Or does anyone have a wiring diagram of ecu pins to main harness so I can check more things? Just looking for an answer of what and why it happened.

[silverbullet02]

One of the switch boxes is possibly bad. Ran into that one time, had spark, or so I thought. Only checked one side but the other was dead and the other was what feeds the ecu. Do you have spark on both sides?

[Reezenbowhunter]

Spark on all 6. Will start on spray but won't stay running and don't want it running that way on rebuild and pre-mix.

[JOE54]

so you say now it wont start with loaner either

[Reezenbowhunter]

It started with loaner while I was double checking spark and looking at plugs I found a broken plug. I changed it and that's when it started. I then plugged in my old box and thought what the hell and it didn't start. So initially I'm thinking bingo it's the ecu. So I plugged loaner back in and now it won't start either. So that was my question to see if there is something that can send a short backwards to ecu and kill it.

[JOE54]

possibly wire harness shorting, does pump run with loaner, fuel psi ????

[Reezenbowhunter]

Pump runs, fuel over 40. Around 42-44psi I believe. Just had power head rebuilt so my question is maybe a pinched wire going short to ground or something causing interference? I'm pretty stumped

[Reezenbowhunter]

Found loose ground wire from cannon plug to behind switch boxes. Runs on loaner ecu and original. Hopefully problem solved? Looking to possibly sell this motor now, has 2-3 hours on it and switch to an Optimax I can get my hands on.

[JOE54]