ZCar Forum banner
1 - 6 of 6 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter · #1 ·
I’m having fuel system problems.

I disconnected the fuel hose between the filter and the rail (and pointed it away from the car) to see how my pump was working. When I turn the key to ON, nothing happens. When I start the car, only then does fuel start coming out. It doesn’t spray out very hard, just a modest flow. Obviously I need to get a fuel pressure gauge, but my question is-

Shouldn’t the gas start pumping when the key is ON?
 

·
Registered
Joined
·
3 Posts
I’m having fuel system problems.

I disconnected the fuel hose between the filter and the rail (and pointed it away from the car) to see how my pump was working. When I turn the key to ON, nothing happens. When I start the car, only then does fuel start coming out. It doesn’t spray out very hard, just a modest flow. Obviously I need to get a fuel pressure gauge, but my question is-

Shouldn’t the gas start pumping when the key is ON?
I have a '77 and the gas will only flow when the starter is on or the AFM flap is open. I installed a pressure gauge between the filter and the injectors to make sure I have the proper fuel pressure, and if I want to get the pump to turn on without starting the car, I usually remove the air filter housing and just push flap slightly open.
 

·
Registered
Joined
·
2,217 Posts
The fuel pump energizes when the engine is running OR if you turn the key to the start position only. Once you release the key the fuel pump will shut off IF the engine doesn't start. If the pump is running with the key on and the engine not running that is a very dangerous scenario. For testing purposes you need to unplug the spade terminal on the starter solenoid, then turn the key to the start position. The starter won't spin but the pump should energize. Much easier to do that way. It's not a bad idea to unplug one of the wires going to the thermal time switch on the front of the t-stat housing before you energize the pump. Z man of Washington
 

·
Registered
Joined
·
19 Posts
If the pressure gauge is connected between the filter and the rail and it is reading low pressure, what is the likely culprit?

in my case, the filter and all rubber hoses are new. Thanks,
 
1 - 6 of 6 Posts
Top