So, when I bought my truck about 2 years ago, the previous owner "didn't know what was in the rear tank". He'd never used it. My plan was to eventually drain it, drop it etc. etc. Well, I still haven't gotten to it, until now...

A couple weeks ago, I was out getting stuff for Turkey Day and the truck died. At some point, the tank got switched to rear. Probably by one of the bag of groceries that I had tossed to the PS floor from the driver's seat... Anyway, tried a bunch of stuff but couldn't get her going. Ended up towing her - literally the first time that I've ever been the tow-ee, not the tow-er. Embarrassing.

Anyway, I finally got around to messing with it today. My plan was to use the drualift to pump most of the fuel out of the front tank (mostly good fuel, other than any bad stuff sent there from the rear tank via the return line) but it wasn't pumping anything. I tried using both a vacuum tester and the oil extractor pump that I have for my boat but I couldn't get any fuel out the feed line at the front of the truck. I tried switching the tank switch back and forth a few times and couldn't get anything from either tank (well, maybe a couple teaspoons). I would imagine that this means that I'm clogged somewhere toward the rear of the truck - possibly the tank switch? I think that I'm just going to dig in and change all of the lines, drain both tanks via the fillers, drop both, clean both, replace both senders (if I can find them for a reasonable price), etc.

Does anyone have any pointers regarding where to look for blockage? Or a sort of how-to on improving the stock system (I seem to recall that some replace the hard lines with all rubber lines?)? Or pointers on proper tank cleaning? Or?

I currently have not touched anything rear of the engine bay but have replaced all of the rubber lines in the engine bay; replaced the stock lift pump with a duralift; and have all new injectors and a new IP. All of this work was done about 1.5 years/10k miles ago. Everything worked perfectly until this happened.

Thanks!

 

I would guess that something clogged up the selector switch. I would drop that out and clear out the lines (compressed air at one end, disconnect the other end). Then drop the rear tank and clean it out.
See if you can suck any fluid out of the front tank line (disconnected from the selector switch). You might not have to clean it out if the switch itself, or the line in front of it got clogged.

 

Thanks tecgod.

Do you or anyone know of a how-to on replacing the lines from the tank to the front? I seem to recall seeing one once that had a list of all of the necessary hose lengths and diameters but I can't seem to find it. I live in Seattle and I'd love to minimize the amount of time that I have spend actually outside in the rain...

 

Sorry, don't have a list off hand. I want to say the feed line is 3/8" and the return is 5/16", but not sure if thats right. My 88 has nylon lines from the tanks to the selector switch, then the feed line has nylon for a little more before transitioning to a metal line that runs up the frame a bit, across the crossmember then up to the fuel pump. At the fuel pump there is a loop of rubber to handle the vibration of the engine. I'm not really sure on the return, but it might be nylon most of the way to the top back of the engine?

The plus with the nylon lines is that it won't ever rust like a metal line, or break down and leak like a rubber line. But they are a little tricky to work with.

 

Okay-

Now, I have both tanks drained; the rear tank dropped and the sender removed. Are there replacement senders out there for these? The only diesel senders (ones with both supply and return) that I can find are listed as being for E-line vans. Does anyone know if theses will work? They're listed as for a 22 gallon tank. I'm not sure the volume of mine but I'd guess mid-teens.

More importantly, the little rubber boot that attaches to the supply line and ensures that fuel is drawn from the bottom of the tank is broken. I can't seem to find these anywhere. Really I'm not even sure what to call them, so even that would be helpful. I don't necessarily need fuel gauges but I do need that rubber boot... On this note, has anyone ever repaired one of these boots with lasting success? JB or something? The main boot is intact but it broke off right where funnel attaches to the metal line - it was glued to the bottom of the tank by the varnishy fuel that was in there.

Also, is there a way to rebuild the existing senders? Tanking the apart and cleaning up the contacts or something?

I also discovered that two of my fuel lines were leaking a bit. Does anyone know where to get the little o-rings for the inside of the fuel line connections? Or do I just take them to the hardware store?

 

There are dozens of threads about the "showerheads" on the fuel senders. If you search this forum you will find answers to most of your questions. Yes the showerheads are available, but many people just put a piece of hose on the end.

I'm not sure about the fuel line connectors. I know you can get replacement ends at auto parts places, not sure if just the o-rings are available or not. However, if you pull out the o-rings, I'm sure you could size a replacement.