Cadillac Repair: fuel pump pressure, voltage drop test, eldorado cadillac

Question
i have a 94 eldorado cadillac and the fuel pump pressure is suppose to be 40-50 psi. With the engine running it's at about 38-39 psi, with the engine off,ignition on i get 40 for about 3 seconds and a drop back at about 38 psi, is this a correct reading or do i need a fuel pump. Thanks for any help.

Answer
1. Key OFF.

2. Install pressure gage.

3. Key ON.

A. If pressure maintains ABOVE 50 psi checkl for restriction and if OK, replace regulator.

B. If it maintains 40 to 50 psi, You have to perform a injector flow/voltage drop test.

Your pressure is on the LOW side of the scale which is 40 to 50 lbs with ignition ON, Engine OFF. Recommend replacing the fuel pump FIRST and see if vehicle runs OK.

If not perform "B" above.