Fuel Pressure

Just for reference if i shut mine off but leave key in on position fuel pressure will take 20-30 minutes if i remember right to get to 0.

 

Did it do this before u replaced fuel lines? If not id go back and check fittings on all lines something wasnt right with that somewhere, if its done this for awhile even before new lines id bet ur pump is worn out

 

Mine has always dropped fuel pressure to zero withing seconds of shutting the engine off. I'm pretty sure this is normal.

 

Did you happen to remove the fitting from the fuel pump return line to the tank? The return line coming out of the pump has a special fitting that is not drilled out all of the way like a normal 90 degree fitting would be, but instead there is a tiny hole thru it....this is a restriction that is built in to the return line to build fuel pressure in the system. If you remove this fitting, the engine will still run, not even that bad, but the fuel pressure will be poor. I saw this at a company where they had mounted a new genset in a power van. The new 550 engine had smaller fuel lines than the old engine they removed, so the installers removed the OEM fitting and changed it to match the size of existing line. The genset would run but you could tell something wasn't right. When the mechanics from Cat arrived to check the low pressure concern, one of the tech's noticed right away that the fitting had been changed and that was the solution. I watched them put the correct fitting back in, adapt it to the size of the line, and start it up. It sounded so much better. Hope this helps.

 

Can you take another picture of the fuel pump from a little farther back, I'd like to see some of the side of the engine too. Thanks.

 

The electrical plug in in your last pic is the computer fuel temp. sensor.
The under black cap is normally a test port for cat.