1993 8.3 M923A2 fuel pressure problem

[dadsoldtruck]

So i just bought a M923A2 with 15k miles 500 hours on it. If I run at full throttle for over 20sec it starts to lose power and if I'm pulling even the smallest hill it will sometimes die. it starts back up and I get 20sec of pull and then back to no power.

So I put a fuel pressure gage on the lift pump. my old lift pump was not great and I got a new one. the new one made tons of pressure 20psi at idle 50psi at 2k rpm. so i drove it and 20min it to the drive same thing.

with both pumps if I power break (load up the motor) after 5sec or so my fuel pressure at the pump flat lines (0psi). it seams to be worst when the motor is warm.

I plan on looking the lines over before the pump to see if its sucking air but I'm running out of ideas fast.

 

[dadsoldtruck]

Well I figured it out. I got algae in my tank. It plugged the intake screen on the lift pump. I drained the tank and installed a inline filter before the lift pump. it has been running better then ever.

 

[Warthog]

Thanks for the update.