Fuel Flow at Return Line? (1 Viewer)

[IBFJ62]

Does anyone have any insight as to how much fuel should be coming through the return line, when jumping the fuel pump to run?

Still trying to figure out a non-start issue after a rebuild, and I just replaced the fuel pressure regulator, which took me from firing up, and then choking out, to now not firing at all..

I've got a little more flow at the return line than I did with the old FPR, but I'm not sure if that's good or bad??

 

[Kleatus]

Never measured it but it’s gotta at least be able to sustain a burn rate of about 7 gallons per hour (working backwards from my worst observed highway mileage.) Thats about 15 oz per minute. Of course that’s not full throttle. If we assume around .50 Lb/hp/hr of brake specific fuel consumption, 150 hp x 0.50 = 75 lb/hr / 6.3 lb/gal = ~12 gallons per hour, or about 26 oz/min. The pump would be sized to still be returning some fuel to the tank even at full throttle to avoid starving the engine, so you should be seeing higher numbers than that.

How much do you have? You can fill up a water bottle and time it to get a pretty good idea what the flow rate is, and see if you can dig up specs for the OEM pump to compare to.

 

[IBFJ62]

A trickle. Like dribble.. And that's after replacing the FPR. No way 15 oz per min.

New fuel filter, new pulse dampener, new FPR., basically new to new-ish everything in the engine bay. I've only got about 1/8th of a tank of fuel however. Could that be screwing me on getting full fuel pressure?

 

[portlandcruiser]

A trickle. Like dribble.. And that's after replacing the FPR. No way 15 oz per min.

New fuel filter, new pulse dampener, new FPR., basically new to new-ish everything in the engine bay. I've only got about 1/8th of a tank of fuel however. Could that be screwing me on getting full fuel pressure?

Any update on this? I am working through a related but different issue on mine.