Along the developing trail of failing parts on my Subaru appears to be my Fuel Pump, but I have a diagnosis question. When I disconnected the harness to the pump and checked the power with a volt meter, power was only present during the starting operations. When the iginition was in the on position no power was present. As for the source of this issue, the car starts great, but tends to sputter and die when running unless you continue to pump the gas.

 

Anyway, if anyone has experienced this previously I would appreciate input as to the no power when the inginition is in ON position, but car not running.

 

Thanks,

JKLEE

That`s normal and proper for a no start.

Yes - when the engine stops running, the FPCU (Fuel pump control unit) will shut off the pump to prevent a fire in case of accident. It will run for a few seconds when it's first put in the run position, and then it will run while cranking. If the FPCU gets no signal from the coil (tach signal, coil pulse, whatever you like to call it), the pump will be shut down.

 

GD

Along the developing trail of failing parts on my Subaru appears to be my Fuel Pump, but I have a diagnosis question. When I disconnected the harness to the pump and checked the power with a volt meter, power was only present during the starting operations. When the iginition was in the on position no power was present. As for the source of this issue, the car starts great, but tends to sputter and die when running unless you continue to pump the gas.

 

Anyway, if anyone has experienced this previously I would appreciate input as to the no power when the inginition is in ON position, but car not running.

 

Thanks,

JKLEE

 

It does sound like the pump is bad. Also check the fuel filter if you haven't already done so.

Its your carby. Needs a clean out. Most likely the primary circuit jets and passages are blocked with gunk. Normal for later wagons to only have fuel pump running when start and not when ignition on.

If it were the fuel pump then pumping the throttle wouldn't keep your engine alive, pumping the throttle does nothing to the fuel pump. If your fuel pump is getting no power then I would suspect the FPCU. These fuel pumps on old Soobs are virtually indestructable. Many ppl have replaced them just 'cuz only to find that the new one they installed is crap compared to the factory one.

 

A quick way to verify that it is your FPCU is to disconnect the FPCU and hot wire the fuel pump. If it comes to life then it's your FPCU. My FPCU currently dies when the temps hit the 30s so I keep a wire with 2 spade connectors to hotwire the fuel pump and be on my way. Hotwiring the fuel pump is a handy survival skill to have no matter what. Just be sure to disconnect your FPCU BEFORE hotwiring. Then have a look at the schematics and it should be obvious which wires should be jumpered.

 

Also note that running with a hotwired fuel pump is ill-advised and UNSAFE since you are bypassing all of the safety features of the FPCU.