VST Pump does not come on

[Hunter#1]

unclip the 6 coil leads.
remove the 8 or so fateners,remove the cover.
the pump is in the VST tank.

Thank you, Rod. Yes, I found the pump and have already replaced that. Was worried about ttaking this coil cover off, not so much now. Thanks again for the info. I wish my service manual gave detail like removing that coil cover so I don't have to ask dumb newbie questions.

[rodbolt17]

unclip the 6 coil leads.
remove the 8 or so fateners,remove the cover.
the pump is in the VST tank.

[Hunter#1]

only thing attached to the coil cover,dual driver 04 and up HPDI, is the coils.
a quick test of the stop circuit? if its activated you get an alarm if you crank it.

pay carful attention to the wakey wakey signals the ECU gets to activate the various relays at key on power.
its all in the harness diagram and its actually fairly simple when you remember typically its the ECU con*****ed ground path that activates things.

Rod , is that fuel pump easily accessible behind that coil cover. If the coils are attached to the cover how do I remove the cover to get to the relay?

[rodbolt17]

only thing attached to the coil cover,dual driver 04 and up HPDI, is the coils.
a quick test of the stop circuit? if its activated you get an alarm if you crank it.

pay carful attention to the wakey wakey signals the ECU gets to activate the various relays at key on power.
its all in the harness diagram and its actually fairly simple when you remember typically its the ECU con*****ed ground path that activates things.

[Hunter#1]

NEVER EVER pierce the wire.
it WILL fail.

paper clips work better.

if the stop lanyard is pulled the pump WONT run.

anytime the key is ON the pump is supplied with 12V on the red wire.
the 12V comes from the pump relay.
the pump ground path is ECU con*****ed.
any red/yellow has 12V when the key is on.

its actually a simple circuit .

Thanks Rod. So if the key is on, and the lanyard attached, and there is not 12V getting to the fuel pump the most likely culprit would be either the relay, or a faulty ground path through the ECU (defective ECU?) Makes sense. I think I'll start with that relay. I see there is a proceedure for testing it in my service manual.

There is a note about not removing the coil cover in the proceedure for testing the fuel pressure sensor becuase the coils are attached to the cover. However in the proceedure for testing the fuel pump relay it says to remove that same coil cover. Kinda conflicting statements about if its safe to remove the coil cover or not without damaging the coils? Which is it, safe or not?

[rodbolt17]

NEVER EVER pierce the wire.
it WILL fail.

paper clips work better.

if the stop lanyard is pulled the pump WONT run.

anytime the key is ON the pump is supplied with 12V on the red wire.
the 12V comes from the pump relay.
the pump ground path is ECU con*****ed.
any red/yellow has 12V when the key is on.

its actually a simple circuit .

[bajakeith]

pinhole

I was never a fan of poking holes in wire insulation that is in a wet or salt environment

well,I sorta agree..if the wire is still subtle it will reseal itself,,,myself use a small dab of liquid electrical tape and that section is stronger and more waterproof than anything else under da hood !! btw the SS peirce is smaller than most needles..but ya gotta spend the bucks and by "fluke" products IMO

[Hunter#1]

The SM is about all that there is. Unfortunately, it is lacking in theoretical information. Pity the poor mechanics that are tasked to work on a Yamaha.

Well I managed to stumble across the electric fuel pump relay. If you tell me the electric fuel pump relay hasn't anything to do with the electric fuel pump either I will scream :-)

[boscoe99]

The SM is about all that there is. Unfortunately, it is lacking in theoretical information. Pity the poor mechanics that are tasked to work on a Yamaha.

[Hunter#1]

Do you have the applicable service manual? If not, get one. Go to the very back where the wiring diagrams are. Follow the yellow wire from the key switch back to the motor and then trace the circuit out from there.

The kill switch lanyard, like the electric oil pump, has nothing to do with power to the VST pump.

Yes I do have it actually. Unfortunately I'm not an electrician. But thanks, I'll look at the schematic and maybe I'll get lucky and figure something out.

[boscoe99]

Does anyone have any idea's on what would have prevented the VST electric fuel pump from having power, besides the obvious fuse or a disconnected laynard on the deadman switch. I would really like to figure this one out, I just know its going to happen again at the most inopportune time if I don't.

Do you have the applicable service manual? If not, get one. Go to the very back where the wiring diagrams are. Follow the yellow wire from the key switch back to the motor and then trace the circuit out from there.

The kill switch lanyard, like the electric oil pump, has nothing to do with power to the VST pump.

[99yam40]

I was never a fan of poking holes in wire insulation that is in a wet or salt environment

[Hunter#1]

Anyone?

Does anyone have any idea's on what would have prevented the VST electric fuel pump from having power, besides the obvious fuse or a disconnected laynard on the deadman switch. I would really like to figure this one out, I just know its going to happen again at the most inopportune time if I don't.

[bajakeith]

well !!

if you go get some "fluke wire piercing probes" that are not cheap $80 for two a red and black,,,,BTW...with ABYC new rules ( a few yrs old now) 12V systems (really 13.8) the standard is now red and yellow..Yep,, That's right and worst marine has no clue (Ya Think !!) on bigger boats than around here we have 110/120 V systems and guys were getting Zapped when testing or installing and thouched a A/C black not a D/C black...OUCH !! that killed a few...back to testing pwr to your pump,,so you hook up these test leads and it will show good voltage or not and will help in a volt drop test if done right.. much better than disconnecting the pump leads and checking IMO for many reasons

[Hunter#1]

Alright, so now the VST pump decides to kick on and the motor starts. WTF is going here? This is a brand new VST electric fuel pump by the way. Something was telling that pump to not come on earlier. It did the same thing yesterday too. But didn't have to wait as long yesterday for it to cooperate. Something isn't right..........ready to slit my wrists with this thing.