With Key on engine off, the fuel pressure should immediately go to 43.5psi +/- 2 PSI
The pressure should hold right about there. Any bleed off could cause no start, hard start or bad performance.
If the pressure drops slowly you could have a leak in a line or fitting or possibly a faulty fuel pressure regulator. Usually if you pull off the vacuum line to the regulator it will be wet if it is faulty.
-Fuel pump testing
(need test light)
The only real good way to make sure the pump is bad is to check for power at the sending unit. The sending unit witch holds the fuel pump is located inside the fuel tank. The other option is to gain access to the electrical harness block at the rear of the car. It is located on the driverís side sub floor in front of the rear end. Locate the gray wire in the harness block. Unplug the harness and probe the terminal that corresponds to the gray wire. With the prime connector jumped with battery voltage, probe the Grey wire terminal at the harness block. Does the test-light light up?
No, Fix short in wire between the fuel pump relay and pump
yes, check for ground on the black wire.
Does your test-light light up?
No, repair ground wire
Yes, Replace fuel pump
95 CAPRICE B4U WHT (SOLD)
6000K HIDs, LEDS, Steelies/Chromed caps W/ Coopers, Grey Bonnies, Gary's Wires, TB bypass, Air Pump delete, CAI, Dual Elec fans
68 BUICK SKYLARK 2D HT--2nd owner, all original, rust free 350/th350, almost ready for paint!
79 Eldorado Biarritz White on White, factory Olds 350