My hrc regulator did that so i took it apart if you are mechanically inclined i recommend you do the same. there is a rectangular piece of stainless steel that is used as a shim valve to bypass fuel. this shim stock is .003 inch thick. it is a piece of shit, mine bent all out of wack after like 20 miles. well i took it out and cut a piece of stainless steel .004 inch shim stock into a SQUARE not a rectangle like the original and replaced it. This plate is pushed on by a piston which determines how much fuel is bypassed and sent back to the tank which in turn regulates the fuel pressure. well i said it before, and i'll say it again, the tolerances, fit and finish of the unit is no good. i took the piston out and polished it to a mirror, and then i made sure everything was sealed up and put everything back together. now my fuel pressure at idle is solid at 57psi and may fluctuate like 1 or 2 psi as temperature fluctuates, but it that is acceptable. and the rise rate is super smooth and responsive. I was thinking of getting the vortech s-fmu also but it is like 300 bucks and it has -6threaded fittings on it so i dunno how other people used it, i guess they swapped all their fuel return lines out. oh well try it you'll like it! lates james
