no start HPDI

[captjoe59]

Did searches and found little to nothing.
If I missed a good post ,please direct me.
I have a 300 hpdi Running fine no issues. My son went to take out while I was at work and when he pulled off the lift stalled. Never restarted again.
His friend brought the laptop and said everything the computer tested was fine. 900 psi at high pressure pump, He said dam thing should start.
All new plugs,cleaned injectors and tested. still wont start.New Battery also. Spins fine and starts with a minor bump of start fluid
My questions are 2
1. Where does the computer measure the fuel pressure at ?
2. Is there a fuse or something I am missing?

My next plan is to start at VST and check everything visually.

Thanks in advance guys,,Joe

[boscoe99]

The computer measures high pressure fuel pump pressure from a potentiometer that is mounted to a fuel rail that is just inboard of the left hand fuel injector rail. A hose mounted to the lower end of the LH fuel injector rail leads to the fuel rail on which is mounted the potentiometer.

If there is a steady more or less 50 psi at the outlet of the vapor separator tank, and 900 plus psi on the fuel injector rail, and it won't light off, I would see if the relay that provides power to the fuel injector driver is getting power from the injector driver fuse.

[captjoe59]

Thank You Another point to check

[rodbolt17]

pull the stop lanyard,crank the motor.
if the alarm goes off the stop and alarm circuits are working.
that engine uses a duel driver setup, odds of both failing at once are high.

myself with 900 psi cranking and the fact it will run if fuel is introduced in the intake, I would look at driver supply and ground issues.

[captjoe59]

Thanks I have twins starboard starts fine,will check it though,does tps sensor drive the injector relay?

[rodbolt17]

the driver is trigged by the ECU based on signals from the pulser coils.

the injector ON time uses defaults plus sensor(various) inputs to the ECU.
there are NO senors that will cut the motor off.

the pulser coils also drive the ign.

[captjoe59]

roger Thank you Rodbolt

[captjoe59]

Rodbolt17 Is there a resource to purchase the test leads referenced in the service manual for electrical testing

[boscoe99]

www.simyamaha.com

Any Yamaha dealer actually.

[captjoe59]

roger thanks

[rodbolt17]

Mar-paper-cl-ip.

[captjoe59]

Thanks

It was just a fuse to fuel injector relay Thanks again guys