300 HPDI no fuel pump ground

[kenigonow]

Hello everyone I have a pair 2005 300HPDI (Z300TXRD)@500hrs. The boat sat up for awhile. Here is what i have done so far.
1.Drain and refill fuel tank.
2.New Racors,primer bulbs,VST pumps, and all 3 fuel filters.
So the starboard motor will start and run. The port motor will not.The fuel pump will not cycle on with ignition key as the starboard pump will.It will run if supplied a ground. I have traced wiring to the relay and then to the ECM.The red/yellow wire to relay gets 12 volts with key on.The black wire is grounded the blue wire has continuity to pump and yellow is good to ECM connector(I think pin#42)
The ECM and relay both send a signal to pump if installed on starboard motor and starboard ECM and relay still no signal if installed on port motor. I have loosened cleaned and retightened any grounds I could find following across and up both sides of engine.
On a side note a friends laptop and YDS software showed only low fuel pressure codes for both motors and YDS will confirm cycling fuel and VSToil pump on both engines starboard fuel and oil pumps actually cycle and port engine fuel andVST oil pumps will not. I'm guessing the fuel and oil pump share a ground path but unable to figure that out with the diagram I have.
Long post sorry just hoping to help you help me.Truly enjoy all the great info on this forum. Thanks for your patience and any advice or ideas. Ken

[rodbolt17]

NO the fuel and VST oil pumps DO NOT share a ground path.
at key on engine off what does YDS say about the stop switch on/off status?

[kenigonow]

Did not have access to my buddy's YDS today... Safety switch was in place but not made. Pulled out reinstalled fired right up. You called it spot on can't thank you enough!!!! So now I'm wondering shouldnt the starboard eng be con*****ed by that or another switch as it is not there is two motors and only one switch ? Also I have done fresh fuel, ringfree,primers,all new filters,cleaned and refill oiling system,lower unit oil, water pumps and t-stats, should I do the low pressure pumps Hp pump belt? Anything else I should look at ?? Thanks again..."WE ARE NOT WORTHY" ....hope everyone has a great weekend !!!!

[rodbolt17]

I would inspect the HP drive belt and tension.
replacing the lift pumps is simply maint.
same as the pressure control valve when you do the water pump.
now you need to test your alarm system.
with the lanyard pulled you should get an alarm when cranking.

a quick test of the remote oil filter/transfer is drain the engine tank,turn the key on.
tach should flash 3 bars,audible will sound and the engine tank should refill in less than 180 seconds.

[kenigonow]

Got it ...once again Thank you !!!

[boscoe99]

Does the kill switch being activated cause the ECU to not ground the fuel pump?

I presumed that only ignition was terminated but...

[boscoe99]

Did not have access to my buddy's YDS today... Safety switch was in place but not made. Pulled out reinstalled fired right up. You called it spot on can't thank you enough!!!! So now I'm wondering shouldnt the starboard eng be con*****ed by that or another switch as it is not there is two motors and only one switch ? Also I have done fresh fuel, ringfree,primers,all new filters,cleaned and refill oiling system,lower unit oil, water pumps and t-stats, should I do the low pressure pumps Hp pump belt? Anything else I should look at ?? Thanks again..."WE ARE NOT WORTHY" ....hope everyone has a great weekend !!!!

On a twin key switch panel, the one kill switch controls two separate circuits. One for each motor. It appears that just one side of yours is failing intermittently.

[rodbolt17]

yes, the stop lanyard will kill the electric pump.
it also shows up on yds.

the poster should have also complained about an alarm when cranking.
that's why I mentioned testing it.

[boscoe99]

Yamaha devotes a number of pages of an owner's manual to rules of the road when operating a boat. Which has nothing whatsoever to do with the motor.

Yet do they ever take a half a page or so to suggest a yearly check of the oil transfer system or mention that failure to start might be caused by a defective kill switch that does not sound the alarm due to another defect in the system? Do they suggest that the kill switch circuit be checked to ensure that it is working? Nope.

[rodbolt17]

its in the service manual under periodic maint. most consumers never see it and most techs seem to ignore it.
its kinda like the oil control valve filter maint at 500 hours on the variable cam timing motors or the cam timing chain tensioner on the f200/225 v6 motors or valve clearence checks in general.
they simply don't get done cause most techs are scared of it.

but yes, that simple test will check the operation of the ECU alarm circuits and the stop lanyard operation.

[kenigonow]

Thanks again you guys there was an alarm after a few seconds cranking ,I assumed to be low fuel pressure ,did not have access to YDS at the time.i have verified oil transfer/alarm operation. I'll check out the kill switch situation.I understand There is a yamaha service bulletin on the oil pumps for these motors that has not been done. The local yamaha dealer said they would take care of that for me on Yamahas dime. Planning on letting them do that, any thoughts around that or anything else you can suggest ? Hope to get this thing in the water soon but wanna make sure they're happy, like to get a couple years out of these then upgrade to 4 strokes.... Thank you again fellas !!!!