Ive had this problem for about a week now. I have a 79 Ford F250 with a 351m. For awhile I would be able to baby it to wherever i needed to go, but one day coming home from work she stalled on me and i couldnt get her started. It sound and felt like it was getting starved on fuel. Its a cali truck w/ all the emissions, and i was going to put a new manifold and carb on it so this seemed the appropriate time. Thinking maybe it was something wrong with the moto 2150 it had in it. After doing the swap she ran like a dream. Its only until shes run for awhile that it starts doing this. It has all new fuel lines, mech fuel pump, even an electrical fuel pump. It will idle just fine for awhile but when i try and drive it, it will go about a block before it will start dying on me. Im pretty sure its not spark and has to be something with fuel. Brand new eddy 1406 on there. can you guys think of anything?

 

I've been there with him the whole time and nothing seems to fix the problem. It's like it only does it when it's warm and driving. At idle you can throttle it up just fine without it cutting out but as soon as we take it around the block it starts cutting in and out and evenventually dies halfway around the block... We even changed the manifold and carb and did away with all the cracked and leaking vacuum erg stuff hoping it was a vacuum leak that was causing it. Any help from you guys is incredibly appreciated. We,ve got our backs against a wall with this one.

 

Possibly a clogged up sending unit? Mine has been acting the same way, I can let it idle, rev it, no problems, get going and it chugs like it is out of gas...check your fuel filter(s)...I have 2 in line filters, one before the pump, and one from the pump to the carb. Possible overkill, but oh well...I need to drop my tank and put a new sending unit and tank on mine...(costs a little more, but I don't have time to drop it and clean it out, let it cure, etc, etc...I can barely make time to drop it and put a new one on...) My thoughts for what it's worth.

Mine started after I ran a bottle of Lucas Oil through it...I should have just went with Fuel stabilizer, but had an extra bottle...wasn't thinking...Lucas Oil is great for "Cleaning" your lines, etc...and also loosening up stuff in your tank...live and learn...

 

Check your tank. Mine was doing the same thing. I rebuilt the carb and replaced the fuel filters and it kept happening. I had to pull the tank and clean it out really good (I did it twice, first time not so good. Second time REALLY GOOD) Mine had a lot of rust and varnish. I suggest pulling the tank and draining it. Put in about 2 gal of diesel and a about 2-4 cups of rocks or nuts and bolts then shake it around on all sides for about 20-30 min. Then put in about 2-3 gal of HOT WATER and about a quart of purple power or some other degreaser and repeat (dont really need the rocks or bolts but this process will help get them out of the tank. Shake it really good and let it sit on all sides and soak. Do this one more time with fresh hot water and degreaser. After that rinse really well with water and let dry (or put in about a gal of gas or diesel and shake and pore out to make sure you get the water all out. Before you install it take the fuel line off your fule pump and blow it out with compressed air. Also check for any bad lines. Mine had one that was really weak and could get sucked flat it the tank became clogged. Slap on a filter pre and post pump and you should be good to go. (I like the clear bigger filter before the pump so you can see how clean/dirty the fuel is)

 

I'd have to double check but i thought we had the same problem with both tanks. And we've blown compressed air through the lines and made the tank bubble. Could it still be clogged? Also both clear fuel filters look normal. I'd think if the tank were dirty it would show in the filters? Thanks for the help guys.

 

Not sure on the dual pumps? I transplanted an engine into mine from a donor that had two tanks, and removed the mechanical pump that was on it (had 2 inlets one for each tank), and replaced it with a mechanical pump designed for one tank...

IF it isn't the tank or sending unit, the next option could be a crimped or clogged hose...as far as blasting air through the lines...I don't have an answer for that...I have thought about it as well, but it is nothing more than a "sock" filter on the tank end, and I am not sure what it would do...but from my experience...if I pull off and put mine in neutral or park, and let it sit for a minute or two, it will run fine for a little while...in my mind I am seeing the suction being released (when shut off), the "trash" falling off of it, then runs fine until it gets stirred back up, and sucks all of it back on...my filters are clean as well (a few very, very small specs here and there), so I'm guessing mine is larger pieces of stuff in the tank, or pieces that are to large to be filtered through the "sock" filter on the sending unit...

Check your lines, and make sure they are not collapsing or crimped somewhere. I plan to do mine this weekend (weather permitting), I will take some good pics and let you know how it goes...

 

That would be awesome. Thanks again for the pointers I can tell you how much that helps. And please do post pictures if you can since that same project is getting higher on our to do list.

 

Took a look at it again today, and i was planning on taking out the electric fuel pump, since i shouldnt need it if the mechanical one works, which is brand new. I crawl under the truck after turning on the ignition just to see if the electric fuel pump was turning on, and it wasnt. Yarded it out, and she doesnt die any more. Im thinkin that the mechanical fuel pump was having to pull fuel through the dead electric pump, in addition to getting it to the engine. Like i said she doesnt die any more but she still sputters from time to time, i think i need to adjust my timing and/or my fuel/air a little bit. No big deal there. I think pulling the tanks are still in our near future, but I live in oregon where it still hasnt hit over 60 outside, normally averaging about 45-50, so I was just trying to wait till it got a little bit warmer.

 

Haha I don't mind it being colder but all this engine work just barely under the cover of you garage while its pouring out is sure getting old... I just want things to dry out lol.