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Topic: fuel pres regulator question (Read 1128 times) previous topic - next topic

fuel pres regulator question

i noticed that the two ports on a fuel presure regulator are interesting and i have a question.

one port is tiny as heck.  the other port is about the same ID as the fuel line.

the large port is fuel return.

the tiny port is from source fuel. 

seems like it would be better if the input port were larger?

On our cars the inlet fuel port is small ,, but on the regulators i have lying around , i compared 80's regulators to 90's and  i notice the ones marked F4 have a larger fuel inlet port.

so i gotta ask,,
does the inlet do the fuel flow "regulation" ,, then the diaphram within regulate the volume of fuel??

fuel pres regulator question

Reply #1
On my Coupe I run an Aeromotive adjustable FPR and the center port is the return to the tank and the outer port is from the fuel rail or on the downstream side of the pump.  This makes the larger port the one on the downstream side of the pump and the smaller one the return to the tank.

https://www.aeromotiveinc.com/product/ford-rail-mount-regulator-2/

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp

fuel pres regulator question

Reply #2
Quote from: Aerocoupe;464833
On my Coupe I run an Aeromotive adjustable FPR and the center port is the return to the tank and the outer port is from the fuel rail or on the downstream side of the pump.  This makes the larger port the one on the downstream side of the pump and the smaller one the return to the tank.

https://www.aeromotiveinc.com/product/ford-rail-mount-regulator-2/


your FPR can only go on one way if your fuel rail is like oem or is oem.
you might wanna look again at the fuel flow.

the fuel rail line fitting closest to the throttle body is the fuel pump supply(tiny fpr port) (should not have a fuel pres test port)
the fuel rail line fitting closest to the alternator is the return to the tank (large port), (should have a fuel pres test port)

Tiny port = from fuel pump or FPR fuel input. 
Large port = outlet to the fuel injectors and back to the tank as the return.


or.....
tiny input port is downstream of the fuel pump
fuel injectors are downstream of the large fuel outlet port.