1983 f250 351W..4 speed manual
Took the truck for a spin yesterday and it stalled going up a fairly steep hill...I started it back up put it in 2nd gear (it has a granny gear) and it wouldn't move..Decided to try it out in 1st and it inched to the top of the hill...I've never had to put it in 1st gear before and have tackled the hill in 3rd gear many times before.
On my way home i was on the freeway and it stalled again..I had no power steering..thinking I would have to coast it to the median i started to veer off..but then as I was coasting going about 30mph i hit the gas and it fired back up again..i did not turn the ignition..don't even know if that is possible...
But i took it out again today to see if I could mimick what happened..and sure enough it stalled going up the same hill.
When I drive it on the road it does not seem to have as much power and get- up..I usually shift at 15mph to 3rd and 25-30mph to forth and it runs fine..but now when I shift at those speeds the truck seems bogged down.
I have no tachometer on the truck so I can't tell you much about the rpms.
Don't have much time to fuss with it now but I hope to check it out next weekend.
What are the likely causes? Not enough fuel? vacuum leak? Just wondering which I should investigate first.
FYI i just did a timing chain replacement so I'll probably investigate my fuel lines first as I had to disconnect them to get the fuel pump off...maybe there a bit clogged.
thanks.

 

As a start I would replace ALL the rubber fuel lines from the fuel tank(s) all the way up to the carb.
Don't say "they look good" as the out sides can look good but the inside could be falling apart and blocking fuel flow.
I would also change out the fuel filter if it has not been done lately.


When was the last time the motor had a tune up? Plugs, cap/rotor and maybe wires need to be changed?
When doing the plug change do a compression test so you (we) know what shape the motor is in.


It is hard to fix an "issue" when it comes and goes like yours so I only picked out what I would do and see if it got fixed.
Only other thing I could think it would be is the IGN box on the fender well.
Dave ----

 

My first guess would be a fuel delivery problem. If you got some crud into the lines, it most likely got pushed up to the fuel filter at the carb inlet. Replace that filter and cut the old one open to inspect it for debris.

Has the truck ever run okay after the new timing chain? Or is this a new problem that started right after that? Just trying to get a feel if something was disturbed in the process.

One quick item to consider is the rubber fuel hose at the fuel pump inlet. If this connection didn't seal perfectly, the pump can draw in air in addition to fuel. This can cause frothing in the fuel feed to the carb.

 

The other guys are leaning toward a fuel problem, but I am not sure the engine would just cut off with a fuel problem. I would think it would stumble and give signs of a problem, and as you let off the gas pedal and pulled to the side of the road, it would sit there and idle fine, but anytime you went to take off or pull a hill(using more fuel) it would start to buck and stumble if it were starving for fuel.

Just cutting off sounds like a electrical problem to me. First thing to consider replacing in the ignition module. If that is not it, you need a spare anyway.

P.S. I could see it cutting off and giving problems if it were flooding out with fuel. Do you smell fuel when this happens?

 

Good point. However, per the original post, it sounds like the engine is way down on power, too. It can be a crapshoot trying to determine whether the fuel or ignition system is at fault in cases like this.

That's why I asked when this new problem started. If it began right after the timing chain replacement, you'd want to revisit anything that was disturbed in the process. For the low power, who knows, maybe the chain was installed incorrectly. Maybe it was something as simple as the electrical connector for the distributor didn't get fully reseated. Lots of possibilities for stuff like that. But regardless of what it could be, I think we really need more details of the timeline to understand when the problem started.

 

It was running fine after I did the timing chain replacement..but I don't drive it too often. I did take it up the same hill though a couple times and never had similar problems...I am leaning toward a fuel issue..When I was replacing the timing chain I observed that the inlet hose to the fuel pump was in pretty rough shape...i think its suppose to have a natural bend to it to go over the long snout of the fuel pump-but I think mine lost its form..that will prob be my first fix..then I will go from there..
I have been researching the part though and haven't been able to find much..the rubber fuel line I am talking about comes off the fuel pump in a loop (oddly designed-the fuel pumps snout kind of forces in the up direction instead of down where my fuel line ultimately runs) then connects to a metal fuel line on the frame..the rubber and metal line seemed to be an all in one part....I've tried finding a similar part but couldn't find anything...I'm not really looking to replace all the lines-money is a bit tight
If this doesn't work I will try another ignition module..I got a spare in the truck.
Thanks guys.

 

Thanks for the extra info about the timeline. I'd go after that suspect fuel line before trying anything else. Fix any known problem first before looking elsewhere.

I don't remember that flex line being part of the rigid line assembly. It was just a short length of flex line, looped in a half circle, with clamps at each end. No idea why it was routed like that, other to allow for movement of the engine on the mounts.

 

You are right...Just went and looked at it does have a clamp...should be an easy fix then.
Thanks