Too much fuel pressure?

[mjrstar]

MINIMUM flow on one of those Bosch 910's is ~130-140 Lph.  

 

Go find yourself a smaller fuel pump, the internal restriction on the reg is going to bump pressure beyond the FPR set point with the amount that pump is trying to flow...

 

option B would be a larger (or modified ) fuel pressure reg, i would say it's inlikely that return line size would have that much effect on fuel pressure unless it's tiny

[kpr]

aftermarket reg's are yuck. i'd run 2 stock regs before doing that.     i think you will be surprised how well the stock reg works.

 

do agree pump  is an overkill.  but checking the fuel pressure properly should be first option. if problem isn't fixed after installing correct injectors

[mjrstar]

If stock reg is capable then stick with it - hence suggestion that the 910 will be heating fuel / flowing way too much (FYI I am hoping the factory evo one in my mazda will be ok for the walbro) although plumbing dual OEM reg's sounds like a right pain in the arse?  

[kpr]

On a 4age rail, would be easy. drill another hole  and couple of threaded holes for the bolts.  since they are flat.    run 2 on my ae85 since using 2 rails.  using both factory fuel lines as return lines  and a ran a big new one for the feed.  044 pump

 

have seen  044's and walbro's run on a single stock reg. cant say i've measure the fuel pressure, as most have been tuned on aftermarket ecu's.    But have checked the afr on a few gt starlets with walbro pumps and stock reg/ecu.  afr  was where it should be at cruise. reg is basically the same a 4age one