Fuel pressure

jaydonaldson · #1 (**permalink**) 10-07-2012, 04:49 PM

What should the fuel pressure be using a holley blue (set at 14lbs from factory) electric external fuel pump with a holley fuel regulator on a 460 around 600 hp. I seem to be flooding everything out and the pump does not shut off. Yes am am wired through a relay.
Just trying to start the car for the first time. 6 to 8 lbs then later 12 lbs other times. The pressure gauge goes from pressure to no pressure then stall.

This is a classic cobra. Holley says the filter and the pump has to be below the tank. I can't see how this can be possible. Does the filter/pump need to be below? Anyone with these problems
Any help would be appreciated
Thanks

Rick Parker · #2 (**permalink**) 10-07-2012, 05:16 PM

What you are experiencing is the pump (@14lbs) initially presurizing the system them overtaking the needle & seat and flooding the float bowls (0 lbs or very low pressure indicated) forcing fuel out of the brass vent tubes and boosters. Set the regulator as close to the carb as possible, about 6 lbs max.

jaydonaldson · #3 (**permalink**) 10-07-2012, 07:14 PM

Thank you

Rick Parker · #4 (**permalink**) 10-07-2012, 07:34 PM

Be sure to check the float levels too.

Gaz64 · #5 (**permalink**) 10-08-2012, 01:21 AM

Quote:

Originally Posted by jaydonaldson

What should the fuel pressure be using a holley blue (set at 14lbs from factory) electric external fuel pump with a holley fuel regulator on a 460 around 600 hp. I seem to be flooding everything out and the pump does not shut off. Yes am am wired through a relay.
Just trying to start the car for the first time. 6 to 8 lbs then later 12 lbs other times. The pressure gauge goes from pressure to no pressure then stall.

This is a classic cobra. Holley says the filter and the pump has to be below the tank. I can't see how this can be possible. Does the filter/pump need to be below? Anyone with these problems
Any help would be appreciated
Thanks

The pump will run continuously, it has it's own internal regulator valve/spring factory set at 14 lbs.

Sounds like your front mounted regulator is not controlling the fuel pressure at the carb.

Are you sure your needle and seats are sealing correctly?

Wind your floats down lower than normal, adjust your fuel pressure reg to near minimum, and work up from there.

As Rick has said, 6 lbs across the rev range should be ok.

The pump head should be at or near to the bottom of the tank, keeps the pump primed at low fuel tank levels.