2013 Yamaha F150 won't idle

[conch1979]

Thanks Rodbolt. I'm still waiting for the boat to be repaired. Last I heard was that a wiring harness had a short causing the fuel injectors to work intermittently. The mechanic was waiting on the wiring harness from Atlanta. Maybe it will be fixed this week...I just want to use the boat

[ashtondahle]

Did you find the solution? My engine is doing the same thing.

[RoosterTail]

you can toss the TPS in the creek and the engine will run, will run in a default but it will run.
the ISC can mechanically stick and over heat the ECU.
the ISC is not monitored for faults.
stuck open and it idles high due to the extra air,stuck closed and it wont idle until the throttle valves add air.

once above about 1800 rpm the isc is at 100% and no longer used.
the TPS simply gives the ECU information on throttle angle.
based on TPS,MAP and crank position sensors,above 113*F, the ECU determines engine speed and load and adjusts ign timing and injector on time according to its internal mapping.

the only other part the ECU does not monitor is fuel rail pressure, its a CRITICAL part of the EFI system but not monitored.

a quick check of the rail pressure while monitoring the ECU with the laptop can quickly eliminate issues.

I notice that the throttle plate has an adjustment to limit the closed position. This is factory preset I presume as there is paint on the thread and lock nut. Is this limit ever adjusted in conjunction with the monitoring of the TPS with YDIS software?