F115 Tach issue

[Hiemester]

Hey Guys, I'm new to the forum and I'm having a unique issue with a digital tach on a 2007 F115. I am installing a new tach and have replace everything new from the engine to the console. New harness, new key switch, assembly, new control and new jumper harness from the key switch to the new digital tach. The tach powers up but just reads zeros. I have confirmed continuity from the tach to the ECU so I know all the connections are good. My YDS can see the tach signal and RPM but it is not getting to the tach. Any body have any guesses'. Thanks in advance.

[rodbolt17]

my guess would be the green wire from the ign switch is not plugged into the green wire on the tach.
tach signal is generated via the ECU on that motor.

[Hiemester]

Thanks for the response Rodbolt. I have checked the green wire multiple times and rang it out to the ECU. I'm pretty sure it's good but I will certainly check it again. I have even eliminated the jumper harness and plugged the tach directly in to the key switch leads with still now success. Any chance the ECU is bad?

[zenoahphobic]

Thanks for the response Rodbolt. I have checked the green wire multiple times and rang it out to the ECU. I'm pretty sure it's good but I will certainly check it again. I have even eliminated the jumper harness and plugged the tach directly in to the key switch leads with still now success. Any chance the ECU is bad?

The engine does run? Check the settings (if it has any) at the back of tacho.

[Hiemester]

I checked the dip switch settings and they are still at the factory default: 2wire trim, four stroke, 12 pole. The engine runs well. The only real strange thing is the rectifier/regulator has been replaced and is hardwired in instead of using the Yamaha plug. I don't know if this would make a difference or not.

[zenoahphobic]

I checked the dip switch settings and they are still at the factory default: 2wire trim, four stroke, 12 pole. The engine runs well. The only real strange thing is the rectifier/regulator has been replaced and is hardwired in instead of using the Yamaha plug. I don't know if this would make a difference or not.

Only if not all the wires have been correctly connected.

[Hiemester]

The red and the black appear to be correct and the three wires coming out of the rectifier are green instead of white but are connected to the whites of the Yamaha harness. this also presents another problem as I can't test it with another rectifier because the plug on the harness has been cut away.

[rodbolt17]

why do you need to test the rectifier ?
battery going dead?

[Hiemester]

The battery is charging fine and pretty sure it's not the rectifier now that I have disconnected the rectifier on my own engine and it still ran fine and the tach worked fine. I'm still just trying to come up with a reason why the tach signal is not coming through. A new ECU is $1100.00 and I hate to buy one to find out it's not the problem. I'm still having a hard time believing it would fail only on the tach signal and work properly for everything else. It's a mystery.