I have a 93 f350 with the 7.3l idi and the fuel filter light keeps coming on and then it stalls. if i pull the filter its half full at most if i prime it it starts light is out and it dosent stall til u drive another mile or two. new ip, injectors, return lines, and fuel lines. cant figure out the issue iv tried changing the filter tightening fuel lines and nothing has helped

 

also seems to be worst when hot

 

Maybe a silly question, but did you put on a new fuel filter. Mine would do the same thing except it wouldn't want to start. I had fuel pressure at the fuel filter head, but the filter would fill fast enough. Replaced it and haven't had an issue since.

 

check your engine oil. see if it is over full. see if it smells like fuel. if it does, your fuel pump is bad.
if not, check your fuel lines for rubs. there most likely is a rub through spot in the fuel line letting it suck air.
also, how much fuel is in the tank? these trucks are known for the fuel pickup in the tank breaking off around the 1/4 tank level.

 

If you can't find anything wrong from the engine to the tank then the problem is most likely in the tank. My tanks were contaminated and it had the pick up tubes plugged almost completely off. My fuel filter light would come on and the truck would stall out and be near impossible to get restarted. I was at a loss as to what was wrong until I saw what was in my tanks, I don't know how it even got enough fuel to idle.

 

just changed the filter about 100 miles ago. but i do sometimes run wmo so it could be clogged. the sending unit in the tank has already been fixed and al the fuel line is new i think i will check the oil and than try changing the filter. the pump was just replaced 2k miles ago tho. tank is full too.

 

new filter didnt help. oil was low but strangly thin. i couldnt smell diesel in it. and i think the issue is my budy barrowed the truck and got gas cans mixed up and has 2 or so gallons of gas in it. would that be the cause?

 

Shouldn't, gas is thinner than diesel. Might make it run rough and clattery, but wouldn't /stop/ fuel getting through.
I'd make sure the gas is diluted, though - 20% gas is about the limit you want to run, I've heard.

 

The lift pump doesnt always dump fuel into the crankcase when it fails. From what you say that would be my next investment, a lift pump.

 

well i will be buying a cheap lift pump this saturday and installing then il be saving up for a good one from international in a week or two. but the issue has almost stopped the more i drive it. i don't get it anymore

 

I am also thinking lift pump is bad.

 

x3,4,5 whatever it is....its your lift pump. I had one that would fuel to get past....but when you rev the engine it would quit.

 

make certain that the water in fuel, sender wire is not mixed up with filter lite. then test pump pressure, replace if the test fails, 1-4 psi is all that is needed, a clog in the fuel line could be a piece of debris that move's and plugs off flow, then when you turn off engine it floats or moves out of the path of fuel, could also be water in filter, dump the filter out in some thing clean, look for water.

 

yeah,this one can be tricky,but least with such a basic old school system there is only so many things it can be lol.
that particular light; "fuel filter" means the filter head assembly is seeing a vacuum and then soon after you see it,she starts to stumble and then stall out as you know.
so basically something is plugged between the filter head,and the rear tank pickup.a broken off pickup screen chunk plugged into the end if the pickup and or line,in front off the fuel tank selector valve or some place in the lines after it perhaps.
im not sure a non pumping lift pump would cause a vacuum and trigger this light? but it wouldn't surprise me i suppose.
actually doesn't this confirm the lift pump is working as the thing making a vac is the lift pump due to the clog? i dunno.

thats's kinds a pita that she's not just keeping the light on and stalling right out,cus if it was,you could rig up a line to a jug of diesel fuel at the lift pump and have it draw from that instead of the tank and see if the light went right out ans idled smooth.would let ya know to drop the tank and investigate there for sure,as you claim you've run new lines.
you know perhaps just as another quick and easy test/rule out,would be to bypass the tank selector with some hose and run 'er for a bit.making sure to have correct lines hooked up.and if she ran fine without triggering the light,you'd know the selector valve is the issue at least without dropping the tank.may not tell ya much else,but least it would rule out one issue and it can be bypassed temporarily fairly easy.just an idea.i think id start here personally (if my beds didn't tip up,making such easy access to the tanks/pickups for quick inspection.)

 

its got to be the fact that gas was in there the issue has almost stopped. i got all happy last 2 days ina row it didnt stalll and no light. i drove for an hour on the freeway light went on off hiccuped ran funny and then ran normal and would do these reapeditly. but only towards the end of the drive and it the light was on it would not roal coal which eads me to think its burning all the way because of gasoline in it and it would explain why the issue is getting better not worse. and the fuel tank selector valve is bypassed already. im still going to get a new pump. the one in it is 3 months old but its an o rileys piece of s*** . and i checked all the line connections all seem to be good. and when the tank was replaced a rubber hose was installed on the sending unit because the plastic pick up tube was broken. when i get money il be replacing the pump but i still think Birtha just dosen't like gasoline at all. oh and i tested the presure at the filter head 4-5 lbs(gauge can't be that accurate) hot as can be or 10 seconds after cold 28 F start with no plug