I recently bought a 1978 D100 Power Wagon. When I first bought the truck it had a couple dead holes. I drove it to my house (about 5 miles) the truck ran like crap but made it. When I was able to pull a valve cover a saw 3 bent push rods. I pulled the other side and it looked good. I replaced the bent push rods and the motor ran great. I took it out for a drive and it stumbled after about 3 miles and eventually died. Gave symptoms of running out of fuel (it had 1/4 tank). After fixing an electrical problem (2 hours) the truck started and ran absolutely great back to the house. Let it sit over night and now I can't drive more than 1/4 mile with out it running out of fuel. I dropped the tank and inspected it for debris. The sock filter had broken and fallen apart. I did not see any other debtis in the tank. No auto parts store had a replacement so I drilled 5 1/8 inch holes in the pick up line to prevent clogging. Replaced the line to the hard fuel line and still no go. any suggestions?

 

fuel pump failure...

you might need higher fuel level to prevent cavation with riged pickup...


try NAPA for sock always had good luck getting older stuff there
The autozone & advance stores often usless kids Gen Xers.

 

thanks for the suggestion.

I have since put full tank. When I bypass the fuel tank and use auxillary fuel jug in engine compartment no issues. Although when I disconnect the line from the fuel filter I can hear air either getting sucked in or being let out

 

gas cap...might have a non vevted on a vented systemt....Or vent return line issue...

try opoerating with cap off or open enough to vent air into sys

 

Disconnect your fuel line from your tank and from your filter and blow some compressed air through it and see if anything comes out. Or from your fuel pump and blow air through it and see if any thing comes out. Make sure you blow the way the fuel flows to make sure that any thing that might be loose goes the same way the fuel does. You might also take your fuel tank out and take it to a radiator shop and have it washed out to see if any kind of lining is starting to break up.

 

The gas cap I have does not seal well at all, I will attempt to operate the vehicle with it removed and see if that cures the problem. As for blowing through the line I did disconnect the line and blew compressed air through the line both ways just to be on the safe side. It produced miinor debris nothing to concerning. BUT as a side note there was fuel in the line. Could this prove vacuum issue?

 

When the sock failed you may have gotten debris into the fuel line. Have you replaced the fuel filter? Have you checked the fuel pressure? You need to tee into the fuel supply line at the carb to get an accurate reading (taken while the engine is running). If fuel pressure is OK, there may still be trash in the carb float inlet valve. If the pressure is low or drops when you give it throttle the fuel line is likely blocked somewhere.
I got my replacement sock thru Advance so I know they carry it.

 

PROBLEM SOLVED!!!!! YAY!!!! There is a small rubber fuel line in the middle of the hard fuel line going from the tank to the fuel filter. That line is over 30 years old and some where along the line had gotten smashed. The line was VERY soft and it's opening to let fuel through was less than 1/16 of an inch. I replaced the line and no more problems. Thank to every one that posted to help. I'm sure I'll have a nother question soon. lol