Awesome!!!
Ok what regulates or shuts of the pump when the pressure is acheived? Or Maintains the constant pressure of the pump??
My Husband found a valve or regulator with gas hoses that go to it underneath the car next the Fuel tank. Is this what regulates the Fuel pressure from the pump?

We are sticking with a Fuel Cell and a external pump for right now cause the original tank is bad and has a hole in it(spendy to replace), Therefore not replacing the internal fuel pump. (being done with all my sons earned money)Thats why this is important so we get this hooked up with out causing problems. This car isn't in the greatest shape but is a project for my son to learn how to fix things on his own. Every advice and diagram you have given me goes to him and he looks it over and discusses it with my hubby first on how and what he is going to do.

So if I am a bother , Please let me know.Thank You for your time. Have a Great Evening

Catrina

 

The fuel pressure is regulated by a fuel pressure regulator on the fuel injector rail. The regulator has a vacuum hose and it opens or closes according to engine vacuum. There is a diaphragm in the regulator that keeps fuel from being drawn into the engine. That is why there are two fuel hoses. One is a pressure line and the other is a return line. Any unused fuel that goes by the regulator is returned to the gas tank. If you are running only one fuel hose right now from a fuel cell you are possibly running too much pressure. The fuel pressure should run about 35 psi.

The fuel pump always runs while the ignition key is on or in the start position. You can always run your own wire to the fuel pump for power. Worst case scenario is run a power wire with a toggle switch.

BTW, you are not a bother!

 

There are only two lines at the fuel pump as bkey pointed out. The return line is usually of slightly smaller diameter then the supply hose. The 3-way valve you refered to is related to the evaporative emissions system and only diverts fuel vapors up to the charcoal canister. Is not related to the liquid fuel system at all.
The relay that supplies power to the pump is called the circuit opening relay and is located next to the engine computer in the center area under the dashboard on the floor. It is in turn supplied with 12 volts thru the 15A "ENGINE" fuse in the underdash fuse box. Doubtfull that the fuse is blow as it also supplies power to the distributor and the EGI main relay that supplies power to the fuel injectors. If that fuse was blown then engine would definitely not be running.

FYI here are wire colors for the circuit opening (fuel pump) relay

Green w/ Red stripe wire : 12 volts out to the fuel pump. Should have 12v here when cranking or engine running.

Black w/ Red stripe wire comes from the starting circuit and should have 12 volts only when cranking engine. This wire and the black wire compose the circuit that closes the relay to provide power to the fuel pump only when cranking over engine.

Black w/ white stripe wire is 12v power supply from the 15 Amp engine fuse. Should have 12 volts anytime the key is in the 'run' position.

Green w/ White stripe wire goes to the air flow meter and provides the ground circuit along with the 12v in from above wire to close the relay and provide power to the fuel pump after engine is running. There is a switch in the air flow meter that is closed and creates a ground path by the movement of the air flow door flap after engine start.

Black wire of course is ground wire.

 

Thank You so much!! That helps Spencer out so much!

He will be pleased to read this now as he has had a hard time finding the reley!

You have a Great Day Babyhuey! Thanks for all your help!


Catrina

 

Hey, new to the forum. was wondering if you could please repost the image/diagram. I've been working on my hatch back 323's fuel system. trying to find the relay and such to troubleshoot if power is getting the pump since it's not turning.