F200XTR HP Fuel Pump not activating

[Andrew1970]

Hello
F200XTR - 1280 hours
Seeking some knowledge as Yamaha Techs away on holidays until mid January and access to YDS not available till then.

Last outing engine wont start, time before no problems.

Completed following:
- has spark and new plugs installed
- has 12.8 volts Dc supply
- Unrestricted fuel flow through to VST
- VST disassembled and cleaned, no debri and filter was clean
- LP pump works when 12V applied
- HP pump works when 12V applied
- checked fuel rail pressure and less than 10 PSI

Testing:
- disconnect HP pump and apply 12v external source and fuel rail pressurises to 40 PSI
- reconnect HP pump
- key ON LP pump activates
- engine will start and run for 10-20 secs then stall and fuel pressure drops below 15 PSI
- after stall with Key still ON signal to HP pump 12 volts is strong to ground however voltage across plug bounces around 0-1.5 V

Indications:
- HP pump is not receiving signal to activate to pressurise rail
- MAP sensor appears operational as key of will rattle

Questions:
- Is there a sensor that if reading incorrectly will stop HP pump operating
- Is their a pressure sensor on fuel rail that could be stopping signal ?
- Other ideas ?

Thanks
Andrew

[rodbolt17]

no sensors activate any pumps.
ALL pump power supply comes from the main relay and pump driver.
you will have 12V between the pumps red lead and ground anytime the key is on.
the ECU supplies the ground path for ALL pump operations.

your next step is going to involve a service manual and the wire harness diagram

[Andrew1970]

thanks
could a failed sensor ie TPS or ICS or another be causing ground issues with the ECU ?
you suggest checking continuity of HP Fuel pump cables back to ECU ?
any other possibilities
thanks
Andrew

[rodbolt17]

like I said, NO sensors activate NOR deactivate the pump.
the only things that affect pump operation, key on power, stop lanyard removed,ECU,main relay,pump driver, and the wireing.
at key on the ECU applies a ground path for about 3 seconds.
without a service manual I cant tell you the exact path.
if you have a service manual the current path is easy to follow.

if the stop lanyard is removed the pump wont run and you get an alarm when cranking.

[99yam40]

Rodbolt to keep the HP pump running what does the ECU need to see.
This may be what he is looking (asking)for

[boscoe99]

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[Andrew1970]

Is the Pump Driver a relay or a component, have you seen it fail
And yes what does the ECU need information from to run the HP pump
thanks

[Andrew1970]

With key ON the LP Pump is running

[boscoe99]

..........

[99yam40]

I guess the RPM is registered in the ECU by a signal from the CPS or something else maybe?

[boscoe99]

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[boscoe99]

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[boscoe99]

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[Andrew1970]

Boscoe correct
The LP pump is running continually when key ON.
The HP is not running.

Regarding sensing RPM. If I apply 12 volts (external power source to the motor) to the HP pump prior to key ON and hence pressurise the fuel rail. Then apply key ON the motor will run normally until the pressure drops (fuel is consumed) then stalls hence if the ECU requires RPM detection to apply ground through the DRIVER it is present however HP still does not run.

Do you think the two issues
1) LP always on at key ON
2) HP not running with key ON are signs the DRIVER is faulty.

IF so what is the part number for the DRIVER

Appreciate your help
Andrew

[Andrew1970]

Fuel Driver unit part number
69J-83306-01-00

Is there anyway of testing ?