Fuel Pressure Black Regulator, not going over 40lbs: advice?

[G-Train]

I've got the Black fuel regulator, and the expensive Weldon Pump, but my Fuel Pressure on a brand new Lavorsi reads 40lbs, it did the same on my previous Gaffrig gauge (both electronic).

I've heard that the Return Line fitting should be specific to the black regulator...is that true, and could that cause my problem?

Any other advice would be appreciated...it's been like this for years, never caused a problem, but it's bothering me. I always thought it was my gauge, until this one reads the same.

Thanks
G

[davemvegas]

i am thinking black reg is 56 lbs. also return line size should not affect pressure.regalators control pressure with spring and valve or check ball.the other varible is if it has vacume port with hose to intake. at hi vacume conditions which is when throttle is closed it will lower pressure a little.when throttle is open vacume drops and it is back to spring pressure keeping pressure at the 56lbs.the only thing that i can think of if 2 gauges read the same 40psi after switching from lower pressure gold reg to hi pressure black is it must be the electric sending unit on motor in fuel rail somewhere that is giving wrong reading to your in dash gauge.

[NICE PAIR]

When in doubt, use a mechanical pressure guage to check pressure. An old oil pressure guage will show the difference between 39 and 56 lbs. I bought a quality mechanical to use when setting up or verifying electrical guages.

[johnnyracer]

I agree with NP. Check with known good mechanical guage. Some of the weldons can bypass internally also .

[patchesII]

I agree with checking mechanically. Fuel return on mine is 1/4". Never had an issue