in-tank fuel pickup

[zippo]

I recently got stuck, ran out of diesel fuel, in my '81 Caddy. A tow to the gas station and a fillup of 11.5 gallons filled the tank (thought it should have been 15 gallons). The Caddy is new to me. The fuel gauge registered just shy of a 1/2 tank and the low fuel warning light never came on. It would seem that either the fuel pickup tube does not extend to the bottom of the tank or there may be an in-the-tank filter that is partially blocked. Any ideas on this?

[Darth Garry]

I thought it was 14 gallons. It may have been that the fumes or foam from the diesel tricked the pump into shutting off early. The pickup is at the very bottom of the tank.

Garry

[zippo]

Garry, thanks for the reply.

[vwcaddydiesel]

quote:Originally posted by zippo

I recently got stuck, ran out of diesel fuel, in my '81 Caddy. A tow to the gas station and a fillup of 11.5 gallons filled the tank (thought it should have been 15 gallons). The Caddy is new to me. The fuel gauge registered just shy of a 1/2 tank and the low fuel warning light never came on. It would seem that either the fuel pickup tube does not extend to the bottom of the tank or there may be an in-the-tank filter that is partially blocked. Any ideas on this?


Had similar problem. Happened twice. 1st time, engine died, checked under hood and saw bubbles in the fuel line from filter to injector pump (I have a clear [1/4" clear vinyl tubing] line - worthwhile altreration if not already on yours - lets you see what is going on; easy to change). After it sat while I was checking, the bubles rose to the filter end and when I tried to start it, it fired right off on drove fine. Went to gas station and filled up - took only 7.5 gal. 2nd time, about a month later, same thing, but when it started it barely ran the rest of way to work (4 blocks). That night it ran fine all the way home. Decided it was time to find out what was wrong - I THOUGHT THE FUEL WAS BLOCKED IN THE TANK, JUST LIKE YOU.
Pulled out Bentley Manual (You say you're new, if you haven't been introduced to Bentley please send me e-mail, I know where there is a copy available) and the section on the tank and pick-up didn't look like a bockage was likely. But still thinking that was it i pulled off the feeder hose at the tank (larger of the two, the other one is the return for excess fuel from the engine)huge steady stream of fuel right in the face - should have planned on this contingency but I was sure it was a blockage - clearly there was NO blockage.

I changed the fuel filter [ALWAYS THE FIRST THING I DO - THEY ARE CHEAP, SO WHY NOT!]

I then changed both fex lines in the delivery system (likely place to suck air but not leak fuel) [rubber hose #1 - fuel tank to metal fuel line at the tank; Rubber hose #2 - from the metal fuel line ((at the firewall)) to the fuel filter] both 5/16". I used Transmission Cooler hose from Napa (supposed to be even better than fuel line and very expensive -$2.77 per foot; but i only needed a couple of feet. While I was at it I replaced the clear vinyl from the filter to the pump. While I had that off i did THE ULTIMATE AIR LEAK TEST:
1. Attach the clear hose to the output of the Fuel Filter.
2. Attach a hand pump (just a simple fuel transfer hand pump (few dollars) to the other end of the hose (if you have 3-4 feet of hose all the better, but the cut length is only 2 feet) anyway,
3. Now hold the pump as high above the fuel filter as the hose length will allow and pump off a gallon or so into a container. After the first couple of quarts the fuel should be free of bubbles (sucking clear fuel from the tank, through the fuel line, through the filter and through the clear vinyl); if not - you've got air entering system. If no bubbles (and you have now created a greater suction (by raising the fuel 3-4 feet above engine, and probably 5 feet above the tank than the fuel pump does) you dont have any leaks.

Keep sniffin' that diesel!

[DragonDiesel]

vwcd - how much is that bentley manual going for?

[zippo]

Vwcaddydiesel, sent you an email about the Bentley manual. Your method for checking for an air leak seems well thought out, I’ll give it a try.