Fuel press directly at pump bleed down time

[sneaky7980]

Quick rundown;
2000 GC 4.0.
New pump and filter/pressure regulator assy installed



Still chasing down pressure problem. Pulled the tank and checked press on the sending side of the filter/regulator combo, got 10psi that instantly bleeds down to 0 when the pump is off. Connected press guage directly to the pump and got a lot more press, (which you should when you deadhead the pump) but it also drops too 0psi within 15 seconds.

My questions are;
1. How long should the pump assy hold press after it's shut down?

2. If my pump is putting out 65-70psi before the regulator, and the regulator is functioning properly, shouldn't it be at correct press (44-52 psi) on the output side of the regulator?

3. What are the chances that my new pump and new regulator are both bad!!??

[dksob81]

Originally Posted by sneaky7980

Quick rundown;
2000 GC 4.0.
New pump and filter/pressure regulator assy installed



Still chasing down pressure problem. Pulled the tank and checked press on the sending side of the filter/regulator combo, got 10psi that instantly bleeds down to 0 when the pump is off. Connected press guage directly to the pump and got a lot more press, (which you should when you deadhead the pump) but it also drops too 0psi within 15 seconds.

My questions are;
1. How long should the pump assy hold press after it's shut down?

2. If my pump is putting out 65-70psi before the regulator, and the regulator is functioning properly, shouldn't it be at correct press (44-52 psi) on the output side of the regulator?

3. What are the chances that my new pump and new regulator are both bad!!??

Well just because it is pumping out 65-70 PSI before the regulator does not mean it is going to be within spec, a pinched return line would cause excessive pressure.

[sneaky7980]

Too much press isn't the problem.

[sneakybert]

The fuel pressure spec is 49.2 psi + or - 5 psi and it should not bleed down below 30 psi in 5 minutes .