General 1G high base fuel pressure

[godfather75]

I just got my laser running and after installing a walbro 255hp I can't get my base fuel pressure below 50 psi. I have a fuel lab afr and 6 -an from tank to rail. Do I have to run a bigger return line? Any help would be appriciated.

 

[logic]

Just to be clear: pump on and engine off, fuel pressure will only reduce to 50psi?

If you only have a 255lph pump, your return line is plenty big (although there could be a blockage). I'd be looking closely at the AFPR.

 

[hhuricane]

It looks like you have the high pressure version. That's probably why you can't go any lower.

 

[godfather75]

I do have the high pressure version. I checked the return line for blockage and the afpr is adjusted all the way out any more and the adjustment screw will fall out. I didn't have a problem with the other walbro when this setup was in my other car only differance is the high pressure 255.

 

[ramsack]

I would think there has to be a blockage in your return line then. A Fuelab AFPR is plenty capable of flowing multiple 255 HP pumps, much less just one shouldn't overrun it. If you could find a way to skip the AFPR and just measure the pressure the system, with the fuel pump jumped to run with the engine off. If it is still high then you have a blockage. If you make like no pressure then your problem is the AFPR. Have you tried any other gauge?