Low Fuel Pressure Help!!

[626Chevelle]

I have a Carter external electric fuel pump (4600hp) running fuel to a Holley carburetor. The psi should be between 5-7 psi. When I start the vehicle its at 6 psi at the carb. Approximately 15 min later it drops down to 0 psi at the carb. I have tested the psi directly from the pump at it drops down to 4-3 psi which is still terrible. Motor is a Carbed LS1

The fuel lines are cleaned and replaced the fuel filter

The fuel pump is new and new fuel tank

The pump has an internal regulator and no strainer inside.

Is this the cause of a voltage problem? If it was a voltage issue, the pressure would be low right from the start right?

Thanks

[HandOverFist]

I don't understand the location of the pump at the rear of the tank...the pick-up is at the front isnt it? It appears the supply line to the pump is coming over the top of the tank...uphill so to speak. Maybe I am looking at it wrong.

[626Chevelle]

The pump is in the rear for more clearance. The pump does have to be lower than the tank. I figured this was ok. Do you think the location is the problem?.

[HandOverFist]

Most electric pumps like to be gravity fed...they push well but sucking sucks. Maybe temporarily alter the location to see what if any effect it has? My only experience using a electric pump with a factory tank/pick-up was a fail. Using a BG400 pump with a factory 3/8" pick-up, pump mounted in front of the tank lower than the pick-up in a '66 Chevelle it refused to keep up with demand. To be honest tho, it was a 850hp 540ci engine...would go like hell to 330' then coast thru the lights @ a 6.70et.

[626Chevelle]

I'm going to relocate it. Hopefully that works. Wasn't sure if it was an electric issue as well