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Chasing a misfire

Dieter said:
On the alternator was thinking take off all the wires, if concern was about back feeding voltage make sure the 12 v hot coming off is removed. That's just my SWAG removing the plug may have 'turned it off'.

It seems like it runs ok until engine is physically warmed up correct? Then runs rich? If that is the case thought would be ECU still thinks the engine is cold? Maybe engine temp sensor (not gauge sender)? You've checked IAC operation and filter is clean? You checked fuel pressure?

Full disclosure I've never had an MPI boat so swagging here. You likely need to find a place to hook it up for diagnostics. I bought the soft ware for my Seadoo for like $400... all to reset the throttle position sensor. Fuel mapping is screwed with out it.
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It seems like it runs ok until engine is physically warmed up correct? Then runs rich? Yes

Maybe engine temp sensor (not gauge sender)? I put a new temp sensor in the thermostat housing but i think there's another one too?

You've checked IAC operation and filter is clean? IAC operates right and is no longer sucking air so bad like it was, however, i don't know if the plunger depth is correct right out of the box? I did a reset and it seems to seal and move correctly?

You checked fuel pressure? 10psi on low side, 50psi on high

So the TPS is brand new BUT upon laying over the engine to get the spark plug wires on the super tight starboard side, i broke the collar off the sensor. It didn't affect the connection at all. And it was disconnected so the plug wasn't affected at all either. I just took some plastic bond and bonded the collar back on it so it would lock in place. I don't think it messed it up but i ordered a new one anyway. If it doesn't help, i'll just send it back. I ordered a MAP sensor too just in case. Again, I can send it back. Where I'm at, it's a lot of outboards and i already had someone come run a scan once but it cost $200!

Are there any other sensors i could look at and test?
 
Temp sensor- they is usually a single wire one for dash gauge and another switch or sender for the ecu. Both would be on thermostat housing or water cross over.

Im getting above my pay grade on this one. Theres a guy on this site mostly in the merc section named Chris from docksidemarine who might be able to chime in if you PM him. Also a guy named Muc cant recall if he is on here or Iboats forum. Both are professionals who ive seen repeatedly give excellent tech guidance, real troubleshooting experience not the BS you typically see on forums…
 
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