Low voltage at the fuel solenoid shutoff. Any ideas?

[genscripter]

I have 0.75 volts at my fuel solenoid shutoff. I checked over all my fuses and they have connectivity.

I traced my wiring back to the barrel connector, which is also putting out 0.75 v.

Do you think this might be a relay issue? I doubt the FSS has a relay for something requiring such low current. Could this be the ignition switch (i doubt it due to the fact that all the other electronics seems to work fine)?

I can jump my FSS with a 12V wire from the battery and the vehicle starts and runs fine. Currently with 0.75V, I'm unable to get the FSS to click when touching connector, nor does the vehicle start (no fuel getting to the injectors, as expected with no power to the FSS).

 

[Vince Waldon]

IIRC the FSS is fed directly from the ECU, so checking connections at the ECU socket itself (and the wiring therein) might be a good step.

 

[KLXD]

The power to the solenoid drops out after a second or so if no attempt to start is made but comes back on when the key is turned to start.

Are you taking this into account when measuring it? Something else may be going on.

 

[Vince Waldon]

Yup, good point, and that's why it's controlled by the ECU in the first place rather than a simple relay off the ignition switch.

 

[genscripter]

The power to the solenoid drops out after a second or so if no attempt to start is made but comes back on when the key is turned to start.

Are you taking this into account when measuring it? Something else may be going on.

That's good to know. I'm checking this on my own (no partner), so I turn the key to "ON" and then walk out to test the voltage. I definitely didn't get the voltage meter on the connector before one second.

If I crank the engine for a turn, then leave the key "on", would that force the ECU to keep the voltage at 12V at the FSS?

 

[Vince Waldon]

It's watching engine RPM, so nope... will turn off the fuel. Safety first!

 

[Steve Addy]

I would pull and check the main 68 pin connector at the ECU first, check continuity performance between the wire at the solenoid and pin 53. If that seems poor or inconsistent then pull the outer cover at the 68 pin connector and check voltage on that wire at the ECU (53) with the ignition switch on (connector plugged in).

If you get the same low voltage at the ECU then it might be the ECU itself...

Steve