So I made some progress today. The first thing I did was remove the pre-filter, then turned the key on to activate the pump and I only had 2 psi. So as the pump was running, I squeezed off the return line from the FPR to the tank and there was no change; still 2 psi. So I removed the post-filter, activated the pump and still only 2 psi. So then I swapped the return line and feed line on the FPR, activated the pump and it went to 0 (zero) psi. So then I bypassed the FPR altogether by removing the supply line from the FPR and connecting it direct to the line going to the carb. At the same time I removed the fuel pressure gauge from the front of the FPR and screwed it into the fuel pressure gauge port on my hard steel fuel line connected to the carb. Then I turned the key on and activated the pump and still only 2 psi. So it looks like I found the problem; a bad fuel pump, which is brand new. GRRRR!!!!! So I just ordered another fuel pump and it will be here Tuesday. I'll get it all installed sometime later this week and see what happens.

 

Well, turns out the fuel pump wasn't the problem. I installed the new fuel pump I just bought and it's the same problem. So that is making me thing that there's a blockage somewhere, possibly the sock/filter on the end of the pickup tube inside the tank. That's where I'm going to start because that's the only thing that could restrict flow from the sending unit to the fuel pump. There's no filters between the tank and the fuel pump because I have removed all the filters (pre & post filters) for troubleshooting purposes. This entire setup (electric fuel pump, fuel lines, fuel filters, fuel pressure regulator) is all brand new stuff and I have this exact setup on my Bronco and it works just fine. So it's got to be a problem in the fuel tank. We'll see what I find when I pull the sending unit.

 

UPDATE......Ok guys so I made a lot of troubleshooting progress today and I've narrowed down the problem, but still don't know what's causing the problem. Without boring you with all the step-by-step troubleshooting details, I'll just give you a summary.

So I installed an inline fuel pressure gauge right at the electric fuel pump and verified there was 5.5 psi coming out of the pump. Then I removed the steel fuel line where it goes into the carb, put the end of the line in a bucket and turned on the key. Fuel filled up the clear fuel filter and flowed out the end of the steel line and into the bucket. So there's no issue with fuel flow or psi up to this point (keep in mind I don't have the fuel line connected to the FPR yet; just straight from the pump to the carb). So then I reconnected the steel fuel line to the carb, turned the key on and fuel would barely trickle into the fuel filter. It flowed so little that there was barely any fuel in the bottom of the filter. So just for curiosity I fired up the truck to see if it would run and it did run, but I have no idea how because there's barely any fuel going into the filter and into the carb. And on top of that, the fuel pressure gauge I have mounted on the hard steel line going into the carb read zero psi, but I had 5.5 psi coming out of the pump.

So bottom line is once the fuel line is connected to the carb, fuel will barely trickle into the filter and I have virtually no fuel pressure. This makes absolutely no sense to me at all. So does that mean there's an issue inside the carb? If so, what do you think the issue it? My next plan of action is to take the top off the carb and see if I can identify any issues with the floats, needle & seat or fuel inlet. Do you guys have any suggestions or advice? Thanks for the help...

 

Fuel quantity is what runs a curbed vehicle, not fuel pressure. Back in the day, those hot Mopars run 3-4 psi. Even further back, gravity feed got cars through mountain passes, even if the Model T had to run backwards. My snow blower blows snow 20-30 feet, it's a beast, it has gravity feed.

If you have only 5.5 psi out of the pump, an Edelbrock will handle that. Try it with the FPR bypassed.

 

Tbear853--The FPR is bypassed; it's not connected at all. Fuel is flowing straight from the tank to the carb. With the fuel line disconnected from the carb it flows lots of fuel (quantity) and fills up the fuel filter, but as soon as I connect it to the carb the fuel filter remains empty and there's virtually no fuel flow at all? This makes no sense to me.

 

With the line disconnected, fuel can push air out of the filter. With it connected to the carburetor, there is a inlet needle pushed shut by the float in the float bowl of fuel so any air in the fuel line must wait until there is room, just as the fuel must do, or else shove themselves past the inlet needle on it's seat. In such case, the air will enter the float bowl and exit via vent, but the fuel following it will cause the valve to be pushed shut.Air in the fuel filter above the exit or out is pressurized just as the fuel is, and the fuel being heavier than air is why you see air over the fuel. Any air trapped in the filter below the exit or out will go to the carburetor before fuel, but you'll only see that happen when you've just finished putting a new dry fuel filter in line.

Try this ...fuel pump to fuel filter to tee with a pressure gauge to carburetor, start, and run it. You can swap the filter and the tee with gauge.

If the sock in the tank is nearly blocked, if you are just running the pump to a pressure gauge, even a very limited quantity will pump up pressure to the pump's best ability. If the gauge is in line to a carburetor, and only can do 2 psi, then the little bit of fuel being used by running the engine is more than the pump can supply at more than 2psi either due to malfunction or blocked supply through the sock. .

 

tbear853--So I pulled the sending unit out of the tank today to inspect the sock. I pulled it off the pickup tube and got my air compressor and blew it out. Not sure if it helped or not, but it was worth a shot. I ordered a new sending unit so when it get's here I might put the new sending unit in and see what happens. At the very least I could install the new sock on the old sending unit.

So if I understand your first paragraph correctly, the air might eventually work itself out of the system in time as the fuel gets used? I just need to keep running the engine to accomplish this????

I do have a fuel pressure gauge port on the hard steel fuel line that bolts to the carb. Will that suffice for what you advised to do? Or do you want me to install the "T" in the rubber hose right after the filter before it connects to the hard steel line?

 

I recall I think you use an Edelbrock carburetor, so it has a single inlet line. A port on the fuel line going into the carburetor will work to tell you fuel pressure going into the carburetor. I use a tee with a short piece of hose for testing and setting, I don't leave it on the truck.

1. Think of your lawn hose. Without a sprayer no\zzle restricting flow from the hose, pressure in the 100 feet of hose is even lower that the gauge in the basement, because it's unrestricted past the restriction posed by the hose bib on the outside wall. This like your fuel pump just pumping fuel out of the tank and onto the ground.
2. Put a nozzle on the end of the hose, but close it and the hose will swell as pressure builds, but it will only increase up to the maximum pressure of your well pump or city water line coming in. This just a fuyel pressure gauge on the end of a fuel line.
3. Open the nozzle to rinse the car your washing, pressure in the hose is reduced. This a carburetor.
4. Another way of thinking, use your thumb to restrict water from the hose to increase pressure to spray Suzie, but we know less water is coming out even at the increased pressure created by the thumb restriction.

Some air will get out of the air bubble in the highest part of your fuel filter as bumps cause the fuel to slosh. The fuel and the air in the filter are pressurized the exact same, so the volume is fixed, but when you hit a big bump, etc, some fuel will slosh up into the air, and then some air will be pushed down enough to see the exit, and being lighter air, will zoom to the carburetor inlet as being pushed by fuel, but as soon as it gets into the float bowl, it vents out the top bowl vent and likely those molecules get sucked into the carburetor throat. The fuel that pushed the air, falls into the liquid fuel in the float bowl, increasing the volume, helping to push the inlet needle shut tighter as the float raises.


Crude drawing.

 

That explanation makes sense. Maybe I'll just drive it around the neighborhood a few times and see what happens. I'm just worried about running out of fuel and the truck stalling because the carb isn't getting fuel. But like you said, maybe all the bouncing and sloshing around will help the air escape. I'll take it for a drive after work tonight and see what happens. Thanks for your help....

 

I had a similar problem with my system. I am using the same fuel pump as you, a Holley non-return fuel pressure regulator and a Mr. Gasket fuel pressure gauge at line where it goes into the Edelbrock Carburetor. Turned out my issue was a dry rotted and cracked rubber fuel line located between the fuel pump (mine is mid-mounted on the frame as I have a rear and an in-cab fuel tank) and the rear fuel tank. It didn't take much of a crack in the hose to admit air and cause loss of pressure from the pump. I only spotted it after noticing a slight wet stain in the rubber line near where it connects to the tank and as soon as I touched the hose, it was obvious what the problem was.

Don't worry about air trapped in the fuel filter. Perfectly normal and will not affect running or proper fuel pressure at all. I'm running about 4.5 psi to my carb as Edelbrocks do not like anything over 5.5 psi or they will tend to flood.

Pics of my setup:

 

Westcoast Highboy---glad you got your issue figured out with the cracked fuel line. All my fuel lines are brand new so I know that's not the problem. So with you and Tbear853 pretty much saying the same thing about the air pocket issue and basically it should work itself out, I decided to take the truck for a drive after work tonight just to see if I'd have any issues and it ran flawlessly. No issues at all. So when I got home I took a look at the fuel filter and it was about 1/3 full of fuel, so that's a good sign. Seems like the air is already starting to work itself out so everything should be good. Just need to do some minor tuning. Thanks for everyone's help and advice.