have a 1996 d250e end dump. replaced filters ...drained tank. on flat ground the truck will move fine. even heavily loaded. as soon as it hits any type of incline it will sputter and cut out like its running out of fuel.it doesnt stall but it gets very rough. it doesnt matter if its loaded or empty. any change in grade will cause the problem. even streeting the truck empty on the road... it gets even worse when the fuel level is below 3/4 of a tank l. doesnt matter what gear its in .mechanic said it could have a hole in the pickup tube in the tank ? hope this isnt the problem as theres no way to replace the tube. theres nothing in the filters...water separator is clean and no water or debris was found when the tank was drained. any ideas ?
Had a buddy who's truck did the same thing. Ended up being a bad lift pump. Gravity works with you when full or on flat ground but when you would go up a hill it would almost die.
Yes. Almost certainly your fuel transfer pump is the problem. If you want to be sure, you can check the fuel pressure at the filter head. The spec will be somewhere around 25psi, but the good old 3306 will run on gravity supply. Another possibility is the piston inside the hand primer can break up and block the flow of fuel through it, but check the transfer pump first.
Another possibility, but probably a long shot, one of the check valves (little dime sized things) in the primer pump can get flipped over somehow, restricting the free flow of fuel throw the primer pump. Where as it runs well when level I very much doubt this is the problem, but it only takes a couple of minutes to pop the primer pump off and check.
I would remove the fuel line from the filter to the primer pump and put it in a clean bucket of fuel and try it. Quick check to determine engine side or filter side.
thanks for the advice and tips. will check it out when its back at the shop