TPS readings for F250 in Yamaha diagnostics

[Mtkalik1975]

I have a pair of F250's which have been running well. I went out in the boat this weekend and the starboard engine will not go above 4000 RPMs.

Plugged into Yamaha computer diagnostics to see if there were any obvious faults, but nothing stands out to me as I don't know what the correct numbers should be at idle.

What should I expect to see out of the TPS voltage output readings? The computer shows two TPS, but they are showing different voltage readings.

I am trained on other platforms, but not this. Any help would be greatly appreciated.

[greasyshaft]

What is the complete model code ??

There are several different models

Both TPSs are built into the ETV and cannot be adjusted

You have two engines that are the same. Why not just compare the TPS voltages & APS or LPS voltages depending on model

Have you checked the basics? e.g. compression, spark and fuel pressure at problem RPM?

[rodbolt17]

it int your TPS,
most likely a fuel issue which wont flag anything on YDS.

the TPS, like the APS, is a two part voltage.
as one increases the other decreases creating a null voltage.

like its been pointed out,its fixed at the factory and non adjustable.

[Mtkalik1975]

Thank you for all the advice. I'll check the fuel supply for restrictions. Are there any hidden filters besides the main inbound and the one on top of the float chamber assembly?

[greasyshaft]

There is two filters within the VST assembly.
One is up top underneath stainless plate
One is bottom of the HP fuel pump.

Best bet is to find a fuel pressure gauge and the appropriate adapter and actually monitor the fuel pressure.

[Mtkalik1975]

There is two filters within the VST assembly.
One is up top underneath stainless plate
One is bottom of the HP fuel pump.

Best bet is to find a fuel pressure gauge and the appropriate adapter and actually monitor the fuel pressure.

OK, understood. I have fuel pressure gauges that are equipped with schrader valve connections. Both high pressure and low pressure capable.

What is the expected fuel pressure range at the VST?

I am very appreciative of the feedback, and will report my findings are i move through this. You guys are great!!

[Mtkalik1975]

Got it solved. After checking all of the complicated stuff, I went back to basics.

Make sure the control cable is moving the throttle linkage the way it is designed to.

The control box feels normal, and the throttle cable is moving in and out. I measured the travel of the sister engine and found that the bad engine is not accelerating due to a faulty throttle cable.

Changed out the throttle cable and engine is working to spec.

Thanks to everyone for the input.