Yamaha ECU with two connectors, tachometer signal pin?

[K447]

On the Waverunners Yamaha changed the ECU in recent years. Prior to 2016 the ECU for 1.8 liter engine has three connectors. I have the wiring diagram for the three connector ECU and found the tach signal on ‘pin-82’ of the third connector.

Now the 1.8 liter engine ECU has only two connectors, with 44 pins each. I would like to identify which pin carries the tachometer signal. On the waverunners this pin is unused/capped and not marked on the wiring diagram. There are many other unused/capped pins on the connectors.

I am hoping the wiring diagram for a recent model year Yamaha boat has the tachometer wiring shown and the ECU pin connection identified.

Can someone point me towards a Yamaha boat wiring diagram that includes the ECU tachometer info?

Thank you.

[KEYZBUM]

On the Waverunners Yamaha changed the ECU in recent years. Prior to 2016 the ECU for 1.8 liter engine has three connectors. I have the wiring diagram for the three connector ECU and found the tach signal on ‘pin-82’ of the third connector.

Now the 1.8 liter engine ECU has only two connectors, with 44 pins each. I would like to identify which pin carries the tachometer signal. On the waverunners this pin is unused/capped and not marked on the wiring diagram. There are many other unused/capped pins on the connectors.

I am hoping the wiring diagram for a recent model year Yamaha boat has the tachometer wiring shown and the ECU pin connection identified.

Can someone point me towards a Yamaha boat wiring diagram that includes the ECU tachometer info?

Thank you.

what signal do you get from plug 1 , pin 8 or plug 2 , pin 47 ?
It is the pickup coil signal wire that goes into ecu and up to dash ( I ASSume that's the rpm feed).
Its the same on the tr1/mr1/1.8 ..
Just diff wire,Same color.W/B . pin 42 pickup to ecu and pin 43 to dash.
I think you need a service manual for the sx210, I looked but could not find in pdf..

[K447]

what signal do you get from plug 1 , pin 8 or plug 2 , pin 47 ?

It is the pickup coil signal wire that goes into ecu and up to dash ( I ASSume that's the rpm feed).
Its the same on the tr1/mr1/1.8 ..
Just diff wire, Same color. W/B . pin 42 pickup to ecu and pin 43 to dash.
I think you need a service manual for the sx210, I looked but could not find in pdf..

I do not have a two connector ECU Yamaha.

On the prior generation three connector ECU the tachometer signal on pin-82 has six pulses per engine revolution. Pin-82 had no factory wire at all on my 2017 SVHO, it was an empty pin location. I added a wire and that provides a reliable clean tach signal.

I presume that six-pulse tachometer signal is generated within the ECU. I suppose it could simply be a repeated signal from a sensor on the engine.

I have never seen a Yamaha wiring diagram that identified a tachometer signal wire on the two connector ECU. That tachometer pin/wire is what I am looking for.

2016 TR-1 two connector ECU wiring, VX Deluxe model IIRC;

Lots of open pin connections, all unmarked.

[KEYZBUM]

plug 1 , pin 8 or plug 2 , pin 47
Is for you to test on the 3 plug ecu..

Its the same on all the wiring, so if it goes from coil to dash you might grab a signal from it/maybe..

edit
I added a pdf with 3 plug pin info

[K447]

plug 1 , pin 8 or plug 2 , pin 47
Is for you to test on the 3 plug ecu..

Its the same on all the wiring, so if it goes from coil to dash you might grab a signal from it/maybe..

Looking at the wiring diagram for my 2017 SVHP GP1800;

plug 1 , pin 8 is W/B wire, goes from pickup coil to ECU. Does not go anywhere else

plug 2 , pin 47 is W/B, goes to the dash. I suppose that could be a tach signal.

My SVHO machines are packed away in winter storage, but someone with access to another could do some signal checking.

Would be really interesting if pin-47 and pin-82 were directly linked, with zero ohms between the pins. This seems unlikely to me.

[K447]

Possibly making some progress.

I/we now suspect that on the Yamaha two connector ECU that pin 29 might provide the same tachometer signal that is present on pin-82 with the three connector ECU.



I do not have access at the moment to a ski with two connector ECU*. If someone does, could you probe pin-29, start the engine and view the signal on an oscilloscope? Much appreciated.

Hopefully the signal looks like this



* Apparently all TR-1 engines use the two connector ECU, as do 2018 onwards 1.8 liter Waverunner engines. I am presuming the 3 and 4 cylinder versions of the two connector ECU would have the same pin for the tachometer signal.

OR, if you happen to have a 2017 Yamaha SX210 boat with the TR-1 engine, an oscilloscope view of the signal that goes to the dash tach would be helpful. Until yesterday I did not know Yamaha even put TR-1 engines in a boat. 2017 year had a regular tach on the dash, apparently in later years the boat has an integrated dash similar to the waverunners.