Injectors won't fire

[Pat Unit]

I have been troubleshooting a fuel delivery isssue on my 2005 fz6 for a couple of weeks now and have narrowed it down to an electrical issue. I tested the injectors individually out of the bike and they all operate fine, but they aren't opening when I try starting the bike. I checked the fuses and they all are intact. Are there any other possible culprits I should be looking for?

 

[Motogiro]

Is the fuel pump priming? When you turn the key to the on position you should hear the typical pump whine for a second, If the pump is not priming there may be a bad relay in a module called the "starting circuit cut-off relay" assembly. There is a plug with 16 wires attached to this module. One wire is red with a blue tracer. With the key on, there should be 12 vdc positive on this wire. If you do not hear the pump prime go back and recheck the fuses. If you find a bad fuse it's likely the result of a shorted wire or a bad fuel pump. replacing the fuse only will probably result in the same scenario.
I remember you did some pump work. If it is a bad relay in the module you should be able to apply positive 12vdc power to the red with blue tracer coming from the cut-off module and the pump will run and injectors will then fire.

 

[FinalImpact]

Do you have a schematic for this? Any error codes?

If not, you need to get one. One detail that may not be obvious is the ECU acts as the ground and does the timing as far as pulse width/injection duration. In addition if the safety protocols are not met by the ECU even if you apply 12v to the injectors, the ecu will not trigger them.
Make sense?

PS - you might go into diagnostic mode and verify both spark and injectors work on both cylinder sets. You'll find this in the tech section under troubleshooting... it is in with the error codes.

 

[bigborer]

1-What is the battery voltage?

2-Are there any errors stored in the ECU?

3-Have you ran the activation mode for the injectors (no 36 activates injector 1 and 4, no 37 injector 2 and 3)? Do they get power?

To enter the diagnostics mode, press and hold the 2 side buttons from the dial panel, while turining the ignition key ON.

 

[Motogiro]

Any news?
Additionally, if there is starter operation the starting circuit cut-off relay is operating. That would mean there should be an audible pump prime. The injector circuit should then be live.
As FinalImpact stated the ECU controls the ground side of the injectors. If the ECU is missing a signal like the Crankshaft Position Sensor (CPS) the ECU will not fire the Injectors or the Spark.
Again as previously mentioned look for error code/s from the ECU. The #12 would be CPS error and would not allow FI and spark.

There are 2 relays in the starting circuit cut-off relay. One relay is the starter and one relay is the fuel pump and injectors. These 2 relays are housed in the starting circuit cut-off relay module. Knowing you hear the pump prime to can be pretty sure the injectors (unless the wire is interrupted) also have 12 VDC.

Please let us know what you find

 

[Pat Unit]

Yes the pump is priming, so what you’re saying is that it must be that the ecu isn’t getting a signal and then won’t fire the injectors? I don’t know if this is the issue, since you said there will also be no spark. I know I have spark, so does that rule it out or could it be a different issue with the ECU?

 

[Motogiro]

Yes the pump is priming, so what you’re saying is that it must be that the ecu isn’t getting a signal and then won’t fire the injectors? I don’t know if this is the issue, since you said there will also be no spark. I know I have spark, so does that rule it out or could it be a different issue with the ECU?

This could be an issue with the ECU. Have you confirmed you have 12 vdc positive at the positive side of the injectors? As bigborer stated you can put the ECU in a mode that will activate the injector sets.
The positive supply for all of the injectors is red with a white tracer wire
The negative side of the injectors for #1 and #4 cylinders is red with a black tracer wire.
The negative side of the injectors for #2 and #3 cylinders is green with a black tracer wire.
These negative leads are controlled by the ECU and if someone has an oscilloscope you could look to see if the ECU is active on the negative side of injector control. I would not do any grounding on the negative side of the injectors while they are still attached to the ECU as we don't really know what voltage state on and off will be so you might damage the ECU switching.

Also have you confirmed by a momentary test that the injectors are in fact passing fuel and not physically clogged?

 

[FinalImpact]

^^ +

As in, you can apply 12v dc to the injectors and they should click on and off when removed.

If the fuel rail is attached, spray fuel. Be very careful with atomized fuel. Very EXPLOSIVE!

You could disconnect the pump, connect compressed air and open throttle plates. Listen for air through each injector via throttle body. This would be a warm fuzzy that injector(s) do something. Little more.

Did you ever verify pump has 36psi?? Very important. Any less and it wont run even if yoi hear it prime.