This is one of my most peculiar projets. Friend of mine has bought a very powerful PWC (personal watercraft or jet if you like): Yamaha Waverunner FX SHO with 1.8litre 4stroke 16valve supercharged engine. It develops more than 200 hp in stock form and owner decided to use VEMS on it for several reasons: 1. original ECU is shot from attaching a battery charger with wrong polarity and it is not readily available. 2. "While you're in there" philosophy of adding more power.

Motec offers Plug'n'Play solution with it's M400/M600/M800 series marine ecus and adapter loom and their documentation has been a great help. Here's a detailed manual of their PWC solution:

It lists pinouts and they have well tuned stock and modified maps for downloading on their site which I did.

This engine has some nice features, few of which VEMS unfortunately cannot use: drive-by-wire throttle and engine data to dashboard (rpm etc). We converted the throttle to vable only already but the dash is not AIM protocol but KL.

Primary trigger

On the crankshaft, pattern unknown since Motec lists it on it's conf file as "REF/SYNC MODE: 62" which means OEM Yamaha mode.

Could the patter be recorded and determinedwith trigger log? Please give input on this.

-- Yes, connect triggers and set it up as a coil type trigger with cam sync active, record a triggerlog and publish, and we can analyze it.

--I finally got the chance to record the trigger log.

9.08.2012: Here's a link to updated trigger logs:

Secondary trigger

HALL sensor on the camshaft, position unknown but could be determined with trigger log.


Engine has 4 COP's (passive) with igniter. Will probably use stepper outputs and no IGBT's

Fuel delivery

4 high-imp injectors, remains stock. Will use 30V flyback.


Drive-by-wire throttle. Will not be used, already converted to mechanical.


Exhaust is watercooled and has a temperature sensor which activates at 96C, lighting a warning light in the dash. Installing a WBo2 sensor will be a challenge.

Miscellaneos sensors for safety

These are wired to ECU connector and should be used if possible.

1. tip-over switch, which should cut fuel or ECU feed when activated.

2. Engine temperature sensor, activates at 88C and should limit engine rpm to 3300.

3. Oil Pressure switch. when activated, lights a dashboard alarm and limits rpm to 4500.

I'm in the process of building the adapter loom at the moment and will try to record the trigger arrangement.

Since original ECU was molded into PU (polyurethan), would it be wise to perform similar thing to VEMS once it is running well? ECU is located under the seat and should not get soaking wet but droplets could easily access it. Also what about the vibration and shocks from riding on the waves?