Fuel Pressure Not Following Boost??

[live2race]

Ok,heres what I got,Double Pumper,1-307 & 1-340,1/2 feed,3/8 return,fuel pressure will spike to 50 psi WOT,25#'s of boost.& then quickly settle back down th 40 PSi,I have checked both pumps to make sure they are coming on,regulator is holding 80 psi,I even teed boost gauge to the regulator vacuum line to rule out ant leaks coming from the vacuum block & im still seeing 25#'s of boost with it hooked that way?when I block the return line with the primary pump,FP goes to 65psi,the secondary will go to 70 psi,could the pumps be the problem? im thinking the pressure should be higher than 65 & 70 Psi with the return pinched off?

 

[y-hate]

it should be higher, re-check everything look for pinch lines or change your fuel filter....

 

[broke1]

307 isnt a hi volume pump after 60 PSI they say you should move to a 340.Both are 255lph pump's.And I alway's thought your return should be just as big or bigger than the feed,dunno.

 

[y-hate]

Do you have a hot wire kit for the pumps?

 

[87GN_70GS]

The 307 shut-off pressure (no flow) is around 90 psi. The 340 is over 100 psi. With the engine off, and a pump energized, turn the regulator all the way up. How high does the pump pressure go up? Does that match the pressure with the return pinched? If so, it's probably not the regulator. Under the same conditions, add air pressure to the reg. Do the pumps track? If it matched the previous two tests, then it's definitely not the reg. Disconnect the return line. With the reg set at 60 psi., one pump should fill a 1 gal can in 60-90 secs. If not, it's the pump(s). HTH.