Yamaha F225 ECU Upgrade

[boscoe99]

An F25TXRD model came with a -30 ECU and a -50 wire harness assembly.

The first F225 with full Command Link capability was an F225TXR model with a production date of April 2005. It used a -31 ECU and a -51 wire harness assembly.

The -30 ECU was replaced by the -31 which was replaced by the -32 which was replaced by the -33. Either can be interchanged with the other.

The -51 wire harness should work with either of the aforementioned ECU's.

The differences between the ECU's is not known to me.

 

[ct1762@gmail.com]

I believe you are saying that the harness will need to be swapped out; however, I'm not convinced of this because @boscoe99 said that my dad's -30 ECU was superseded by these later models. This means the pinout must be the same for the newer ECUs to plug into and work with a -50 harness. Since there is already water temp sensor wiring/connector (though it appears no water pressure like with the -51 harness) then I'm thinking it should work.

i think you are being a bit paranoid about engine temp. Im an outboard rebuilder, and the only times youd see an overheat is from sucking up weeds at idle (would need to be a huge patch of seaweed to wrap around the gearcase to drop pressure at intakes) or a clogged t stat but these issues are extremely rare once on plane as 20 psi of water pressure cleans these components. plus as mentioned you have the alarm (a solid tone is overheat, intermittent should be oil related) and ECU limiting rpm. just sounds like he needs to know a solid tone is overheat.

 

[MyTie]

@boscoe99 wrote (and rewrote) "The -51 wire harness should work with either of the aforementioned ECU's."

It was clear (both times) that the -51 wire harness would work with all the aforementioned ECUs, what I was asking was if the -50 wire harness would work with them.

@ct1762@gmail.com: Thanks for the info about the limited times you've seen these engines overheat. Problem is that my dad cannot hear the warning tone (solid or intermittent doesn't make a difference). The reason I started the thread in the first place was because my dad had been driving the boat for months with the oil pressure alarm activate e. It was sounding off continuously while using the boat but he couldn't hear it. Thankfully, it was just a bad sender but I don't like that he can't hear any of the warning signals (they are there for a reason). Additionally, the tiny little icons on the round CL are virtually impossible to see at speed.

 

[boscoe99]

The -50-00 wire harness will not work with the later ECU's.

Would be very simple to wire a bright red light on the dash to indicate the nature of the warning alarms. One for temperature. One for oil pressure.

Or to wire in a larger warning horn.

Now with a problem resulting in the warning horn sounding, and lights illuminating on a Yamaha tachometer, the ECU should put the motor into RPM reduction mode. Which makes it run poorly. At a low RPM. That should also be a sign to someone that the motor should be inspected to find out what is going on.

 

[MyTie]

The -50-00 wire harness will not work with the later ECU's.

Would be very simple to wire a bright red light on the dash to indicate the nature of the warning alarms. One for temperature. One for oil pressure.

Or to wire in a larger warning horn.

Now with a problem resulting in the warning horn sounding, and lights illuminating on a Yamaha tachometer, the ECU should put the motor into RPM reduction mode. Which makes it run poorly. At a low RPM. That should also be a sign to someone that the motor should be inspected to find out what is going on.

Good info, thanks. Seems to me that since the -30 ECU has been superseded by the -33 ECU then it should work with the -50 harness (albeit not the additional functions I was looking for).

I understand how to wire in a bright light to coincide with the sounder (which is on my list) but how does one wire in separate ones for temp and oil pressure?

For whatever reason, his 2004 (manufacture date) engine didn't go into RPM reduction mode. There was absolutely no way to tell anything was wrong since he couldn't hear the alarm (or see the tiny check engine light blinking, which I also couldn't see without really staring at it).

 

[99yam40]

very strange it did not go into RPM reduction when the alarm was sounding if it was for low oil pressure or over temperature.
not sure how that can happen if the ECU is the one that sees and responds to the sensors saying they saw a problem.
could it be that the ECU just lost contact with the sensor, so it was not telling it there was a real oil pressure problem, maybe just a problem with the system that needed fixed

 

[boscoe99]

Good info, thanks. Seems to me that since the -30 ECU has been superseded by the -33 ECU then it should work with the -50 harness (albeit not the additional functions I was looking for).

I understand how to wire in a bright light to coincide with the sounder (which is on my list) but how does one wire in separate ones for temp and oil pressure?

For whatever reason, his 2004 (manufacture date) engine didn't go into RPM reduction mode. There was absolutely no way to tell anything was wrong since he couldn't hear the alarm (or see the tiny check engine light blinking, which I also couldn't see without really staring at it).

There is a connector on the motor that provides the grounds to illuminate lights within a conventional Yamaha tachometer or icons within a Yamaha multifunction tachometer. Those grounds could be wired to a relay that would then power a much brighter light at the helm.

A relay so that current from a bright light does not exceed whatever current the ECU can handle.

If different sounding warning horns were to be used then those different sounds could alert someone as to the reason (low oil pressure or over temperature) for the alarm.

 

[MyTie]

very strange it did not go into RPM reduction when the alarm was sounding if it was for low oil pressure or over temperature.
not sure how that can happen if the ECU is the one that sees and responds to the sensors saying they saw a problem.
could it be that the ECU just lost contact with the sensor, so it was not telling it there was a real oil pressure problem, maybe just a problem with the system that needed fixed

Not sure, as outboards are new to both of us. All I know is that I was on the boat with him when it was happening (one of the many times he drove the boat like that) and there wasn't any RPM reduction.

Also interesting is that, when I unplugged the sensor (at a later time), nothing happened at all. No alarm, no warning, and when I pressed the mode to cycle through the various indicators, the oil pressure 'screen' was missing. This tells me the ECU was able to see the sensor which was providing faulty readings. Additionally, the ECU and the round CL gauge were the only NMEA 2000 devices on the boat (until I installed a chartplotter for him).

 

[MyTie]

There is a connector on the motor that provides the grounds to illuminate lights within a conventional Yamaha tachometer or icons within a Yamaha multifunction tachometer. Those grounds could be wired to a relay that would then power a much brighter light at the helm.

A relay so that current from a bright light does not exceed whatever current the ECU can handle.

If different sounding warning horns were to be used then those different sounds could alert someone as to the reason (low oil pressure or over temperature) for the alarm.

More good info, thanks! I understand all about relays, just didn't know that there were separate grounds for oil pressure and temperature.

I'm also working on a solution to get the temperature to display on the chartplotter (without swapping the ECU and wiring harness, due to the expense). I'm getting close, just need time to get back to his boat.

Oh, and the chartplotter announces the warnings/errors in plain English with a confirmation button that needs to be pressed for acknowledgment. This is a huge plus as the alerts are very noticeable.

 

[99yam40]

do you know how the oil pressure and temperature is measured by the ecu?
Are the sensors variable resisters that send back a variable voltage that the ecu converts to pressure and temp?

seems the old school thing was just switches that connected to ground when they were out of spec.
now a days I believe oil pressure can be too high or too low for a set RPM to cause an out of range alarm.
maybe temp is the same

 

[MyTie]

do you know how the oil pressure and temperature is measured by the ecu?
Are the sensors variable resisters that send back a variable voltage that the ecu converts to pressure and temp?

seems the old school thing was just switches that connected to ground when they were out of spec.
now a days I believe oil pressure can be too high or too low for a set RPM to cause an out of range alarm.
maybe temp is the same

Yes resistance/voltage vary. The sensors are three wire sensors, there is a reference voltage (I believe it was 5 VDC), a ground, and the sensor (output) voltage to the ECU (which is the one being monitored).

The oil pressure sensor was the one that was failing. Most of the time the little circle that goes from low to high on the oil pressure screen was pegged at high. There was not way to get an actual value (unlike with the chartplotter). However, after shutting it off and restarting it, it was pegged low (and also in alarm). This is what led me to believe the sensor was bad so to confirm this was the case I unscrewed it and installed a mechanical gauge.

In doing so, I unplugged the sensor and that's what led me to discover that if the sensor is unplugged there isn't an alarm, or any indication that the ECU isn't receiving valid sensor data (other than the associated 'screen' disappearing from the round Command Link gauge when cycling through the various screens with the mode button).

The part that's confusing to me is how the round CL gauge is able to read the temperature but not the chartplotter. However, there are numerous web articles describing this to be the case with engines built prior to 2006. My guess is that Yamaha is using either a different field within the NMEA 2000 127489 PGN for temperature, or possibly, they are using a separate PGN altogether (130312 is a depreciated temperature PGN, maybe this is one?).

While the answer isn't critical, it has piqued my interest so I contacted a buddy who has a NMEA 2000 bus analyzer and asked him to swing by my dad's to take a snapshot of the data on the bus as his time permits (he's a busy guy so it might be awhile). I'm hoping it will provide the answer to this mystery.

 

[99yam40]

cool, let us know what you come up with.
Alarm going off and not limiting RPM to around 2K makes no sense to me.
I guess that is what that motor is suppose to drop it to