Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.
I'm out and about for the evening. I'll give that all a test tomorrow, gaps should be accurate but I'll double check. But yes, everything is fresh, new cam too. Basically the block, wiring, and belt components are original. Most everything else has been replaced. This was given to me for nothing, and I don't have a car payment, that's why I've had no issue just replacing everything. It was in gnarly shape and been a fun rebuild... And now I'm frustrated hahaWhat plugs did you screw in it? Proper gap?
Have you pulled them to read them? I would think if it was a low fuel pressure issue... the plugs would look near white.
So I think the depressurized system was a fluke or one off.. I replaced ALL the lines with nylon 5/16" yesterday. Before doing that, I bled the system again, and lo and behold there was pressure. I replaced the pump with another brand pump I had, same with the regulator, and there was no change. Haven't had a chance to check the plugs yet, and I'm going to recheck timing too. I think it's safe to eliminate the fuel system since I confirmed neither pumps nor regulator, and all lines have been updated and replaced along with new motorcraft filter . Unless someone has other thoughts/suggestions!Since it doesn't hold pressure after shutdown, we can temporarily ignore any non-fuel problem and focus on fixing this one.
Fuel pressure has to be bleeding off somewhere (seems obvious, but stating it mostly as I step through it in my head). So the question is how to narrow that down. The obvious culprits would be an external leak (which ought to be pretty obvious with a good visual search), the fuel pressure regulator, and the check valves in the fuel pumps.
If you pressurize the fuel system with key on and then immediately disconnect the return line from the FPR, do you continue to see fuel leaking from the FPR?
Is there a spot in the fuel system where the lines could be clamped after each pump? From memory it's almost entirely hard lines, but if there's anywhere that you -can- clamp, that ought to eliminate fuel coming back through the supply side. If the act of clamping stops the pressure bleedoff, then that would seem to indicate a bad check valve on the upstream pump.
I replaced ALL lines yesterday with new 5/16" nylon while digging in there. Filter was replaced with new motorcraft too. No leaks and everything is appropriately tight.I would think none of the engine, ignition stuff would influence the fuel pressure - should that not be a relatively simple issue, of (1) fuel in tank (2) pumps moving it to the fuel rail via (3) the pressure regulator?
Given pressure regulator and pumps are likely to be good, the other suspects then become the tank and the lines/filter. Could there be obstruction in the lines and/or filter?
I suppose the other possibility would be a leak somewhere 'downstream', meaning after the regulator, in the fuel rail or one or more leaking injectors. But injectors were checked/swapped, so maybe somehwere in the fuel rail a leak?
I'll give this a try today. Any chance you know correct voltage reading?Have you checked the voltage and ground at the HP pump?
Maybe run jumper wires to the HP pump from battery while running and check pressure?
Also.. fun, frustrating update. I'm in the process of moving 40 mi north of current location. Yesterday was the inaugural trip in the B2. Flooring it the whole way, could barely make 55-60mph on straight aways. A couple times as I would shift to neutral to coast, the engine would stall out. Was able to restart while coasting, but happened twice there and once heading home.Hmmm... voltage drop on the fuel pump circuit. Worth consideration... easy enough to check.