fuel pump question

[tpnotch420]

I have a 92 sc400 and I'm recently having a problem getting it to start. I notice that when I insert the key I can't hear the fuel pump running so I decided to try the fule ecu bypass. After completing that the fuel pump fires right up without having the key inserted and the only way I can shut it off is to disconnect the jumpered wires. Anyone know what might be causing this? Any help would be greatly appreciated

 

[Peewee]

If you have the bridge/bypass between +B and FP then the pump should only run with the key ON.

If the car doesn't run without the bridge in, and runs with the bridge in, then you need to replace the Fuel Pump ECU.


EDIT:
Under normal circumstances the pump will not run unless the car is running or the key is in START.

 

[tpnotch420]

Yeah I get that what I'm trying to figure out is what is causing it to run without the key and why it won't shutoff on it's own

 

[Peewee]

What exactly are you doing for the bypass ?

 

[tpnotch420]

I'm jumping 2 wires going the the fp ecu. When I connect the wires the fuel pump turns on before I put the key into the ingnition. The wires I'm connecting are green and red/black. I found a couple of how to's and followed their instructions. Now I'm wondering why the fp comes on without the keey and why it won't shutoff

 

[Peewee]

The FP ecu should not have constant power, it should only have ignition switched power. Make sure the M-REL relay (engine bay fusebox - could be called MAIN or EFI MAIN) is not stuck on.

 

[tpnotch420]

thanks for the suggestion I will check that out and let you know the scoop