2003 yamaha 4 stroke, injectors not spraying

[turn2]

The motor will run, just not right. I pulled the injector log , turned the ignition on and none of the 4 injectors will spray. I can ground the wire that is not hot and it will spray. To clear things up. The injector plug has 2 wires, red with yellow stripe,and white with other color stripes. The red yellow is hot on ignition and the other has no ground or hot,but when I touch it to ground the injector sprays. All the wires run to the front of the engine to the module. Is the module that sends the pulse to the injectors a suspect ? Any help would be greatly appriciated

 

[seahorse5]

Re: 2003 yamaha 4 stroke, injectors not spraying

The system works by having 12V at all the injectors, but the ECU completes the ground circuit for the correct amount of time, which opens the injectors and allows the fuel to flow.

 

[jeffersondodson561]

Re: 2003 yamaha 4 stroke, injectors not spraying

If you get a test light and hook your lead to 12v positive and probe the ground side of the injector lead and key on/start engine, see if your test light lights up. I think that once the rail is pressurized the injectors pulse before engine starts up. I would also check all grounds for the ECU and injector driver(s), I don't know what HP your talking about.

 

[turn2]

Re: 2003 yamaha 4 stroke, injectors not spraying

The system works by having 12V at all the injectors, but the ECU completes the ground circuit for the correct amount of time, which opens the injectors and allows the fuel to flow.

So if they dont spray the ecu is bad?

 

[seahorse5]

Re: 2003 yamaha 4 stroke, injectors not spraying

So if they dont spray the ecu is bad?

Have you tested to see if there is the required fuel pressure in the rail?

 

[turn2]

Re: 2003 yamaha 4 stroke, injectors not spraying

with the key on I can ground the stripe wire and the injector sprays fine, just not when turning the motor. the motor is a 115

 

[jeffersondodson561]

Re: 2003 yamaha 4 stroke, injectors not spraying

with the key on I can ground the stripe wire and the injector sprays fine, just not when turning the motor. the motor is a 115

I know but before the motor starts it needs to enrich fuel to the cylinders, it does this right before start up through the ground applied by the ECM.

 

[turn2]

Re: 2003 yamaha 4 stroke, injectors not spraying

So if I have the injector log off and I turn on the key the injectors should spray briefly before the engine starts? These are not spraying at any time. When I pump the bulb and turn on the key it will blow off the top injector, but it does not continue to spray fuel out. If the fuel pump stops working will it cause it not to spray??
Thanks Danny

 

[jeffersondodson561]

Re: 2003 yamaha 4 stroke, injectors not spraying

No not when you turn the key to the on position, when you crank the engine it does this. Tell me how you have determined this by the injector log? Have you checked timing yet?