That's the fuel heater, and it's a fairly common spot for fuel leaks and air intrusion (the reason it's hard to start first thing.) There are 2 (IIRC) O-rings around the beige plastic part underneath the filter head. Remove the filter element, fuel inlet and outlet, and any hoses and wiring, then unbolt the filter head. The heater is held in by the filter nipple, remove that and you can pull the heater out. Install new O-ring(s), lube with Vaseline, and install the heater. Assemble everything in reverse order.
If the fuel is leaking around the beige part just replace the O-ring(s). If it's coming up through the beige part, you can try to seal it with epoxy or just replace the heater.
The part in your 2nd post is the fuel heater connector body, I highly doubt it's available separately. I'm pretty sure a 3/16" female spade terminal will work, you probably won't find them at Autozone or O'Reilly though.
Yep, that's the story. Unless the heater itself has cracked, which is entirely possible. Point is, that cap's job is not to keep fuel in, it's to keep dirt and other contaminants out of the plug. If you can afford it, it is prudent to keep a spare heater on hand in case it fails. (I don't have a spare any more, I'm running on it!) And it's nice to have on hand when you disassemble the filter head (I did it on-vehicle, actually, which makes it pretty simple) so that if the old one is broken, you have it to install.
1992 F250 XLT 4x4 Super Cab 7.3 IDI E40D 3.55 ATS 088 4"R.C 360k
1982 MBZ 300SD W126 California model w/Sunroof, no EGR
Same issue on mine only it was the internal seals in the thermistate that had failled. replaced the heater and well damn, it works like a trick now.
__________________ New truck: 1988 F-350 1 ton dualy 2*4, 7.3L IDI Naturally Aspirated, Dual tanks with Camper package. Mods: Enhanced gauge cluster; Transmission temp, rear diff temp, coolant system pressure, Vacuum pressure, Fuel pressure, Crappy tire Air horn Kit, Raycor pre filter/water sep. All LED Dash lighting, thinking of adding an electric blower for mild boost.
Generator sets: Honda 3.5Kw (Fixed and running!) Onan 3.5Kw Electric/Remote electric Start. Remote start pannel made and hooked up, I love it!
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.