BioFarmer93
OPEC Hater
I agree, it is a simple fuel circuit. That being said, these trucks are old and a lot of them have been wrenched on inexpertly for a lot of years. As far as I'm concerned the one way valve needs to be in the (stock) vertical hard line from the lift pump to the filter head, but hey, I don't work for FoMoCo. Looking at the air intrusion issue from a gravitational standpoint, the return line to filter head is the usual entry point for air from leaky return hoses between injectors. I realize there will be differing opinions from plank owners here, but I really don't see a good reason to have that particular link in the chain. If the lift pump is doing its job properly, and you're not pinching pennies on fuel filters (as in putting in a fresh one when necessary) then no pressurization of the return side is needed. In one of the photos I posted you can see a small nylon tube coming out of the fitting on the near side of the fuel "T" after the filter. That goes to the fuel pressure gauge mounted on the hood. I'm only interested in "after filter" pressure, as that tells me everything I need to know. Billy may have used an unfortunate choice of descriptive term with "chaos"... My stuff is totally K.I.S.S.. The only extra on the underhood portion of the fuel system is a shut-of valve on the vertical leg of the (all black diesel hose from FSV to IP) just before the filter to help keep drain down to a minimum when changing filters and to make priming the new filter just a matter of turning the valve off, opening the line after the filter, turning the pump on and then opening the valve until fuel fills the filter and starts to squirt out the open side. Then you just slam the valve closed real fast, turn off the pump and leisurely reconnect the hose between filter and IP.
