So truck has electronic fuel pump, at times fuel pump will lose its prime, you can hear the pump running but it loud cause it's not picking up gas. However, if I pour gas down carb to get truck to fire up the fuel pump will start picking up gas and everything is good to go. This is a new fuel pump, old fuel pump had similar issue

 

Where did you buy it? and what kind of pump? I've had the same issue's with napa pumps.

 

Bought it at oriellys, Edlebrock brand.

 

do you know if it's a vane style pump or diaphragm ?

 

this is the one

 

 

You almost got it, where is the pump mounted.
I would say 99% electric pumps do not pull fuel they push.
Also look at all factory pumps they are mounted in tank so the suction in close to what it is pumping.
After market pumps should be mounted as close to the tank and below the fuel level as you can.

I hope you are running that pump thru a relay so it gets full power and a safety switch like an oil psi switch so pump will not run if motor is not running lime if in an accident.
Dave - - - -

 

Pump is mounted on outside of frame in the area of where the bed and cab meet. It is wired with 30amp fuse and is manually turned on with toggle switch which I plan to wire to ignition switch. I will look up and see about a safety switch I hadn't thought about that.

 

that's where I was going some pumps are pull some are push

 

X2 on most elec pump need to be as close to the fuel source as possible, like on the cross member right in front of the tank. And they do not like to be ran dry at all.

And X10 on better to be wired to a easy or commonly killed power source (ign key) in case of an accident. Great idea here. Electric Fuel Pump: How to Do It Right

Why do you not have the OEM mechanical pump on the motor?

 

2 to 3.5 psi is not very much pressure at all unless you are just helping a stock pump for some reason

 

So have an update with this issue, I have noticed that when the truck loses it prime and it wont suck fuel from tank I can remove gas cap releasing pressure and it will work and prime up. Any ideas as to what this is caused by?

 

Wrong gas cap or one that is not venting. You need a vented cap.