Team -

Need some help. I recently bought a 1977 Ford Camper Special F-250. I have been having problems keeping it running. It will run for about a minute, and when it gets warm it cuts off like just as the key was switched off. I thought it was the Fuel Pump, so I replaced the fuel pump. The truck ran yesterday after the fuel pump replacement, I could see the fuel going through the filter. Today same problem... Ran for about a minute, then cut out. I dont know what to look at. Drop the Fuel Tank? Ideas on eletrical causes? Anything I should check out?

Joel

 

You'll need to provide a little more information. Will it restart after it cuts off? Have you checked for spark after it stops? Doesn't sound like a fuel problem, but have you tried some starter fluid or gas in the carb to see if it will fire when you have the problem?

 

Ign module?

 

Agreed, have to check for spark. No one can suggest fuel pump, ignition module, etc until you've actually diagnosed the problem.

 

Why did you first suspect a fuel pump? Remove the air cleaner and look into the carb throat as you cycle the linkage and you should see fuel spray from the accelerator pump shooters.

 

Ok I have a bit more information. I believe it is fuel related still. I have been able to squirt gas into the carb input line and it will run for a minute or so.

Here is the part I am uncertian on. The symptoms only occur when the truck is pointed downhill. If I move the truck and point it uphill the fuel pump appears to work, it stays running, will restart every time and I see fuel coming through the filter.

So does that tell me that there is a fuel tank/line issue from the tank to the fuel pump?

Joel

 

Intermittent problems are hard to solve so dont try to make guesses, your engine needs three things to make it run, compression, fuel and spark. Your engine does run at times so you can assume compression is good, that leaves fuel and spark for you to check both of which are easy to do, once you find out which one it is take it from there and we can help you better. Good luck

 

Thanks for the help so for. I took the fuel inlet line from the pump and blew back through it to the tank. When I re-connected it it did show a leak from the fuel pump outlet line to the engine, which I tightened and it stopped.

Other than that same symptoms, runs, pumps gas when level/pointed up a small grade, when ideling stopped pointed downhill fuel pump stops pumping gas and it stalls after using up the gas in the carb. I refil the carb using a squirt bottle into the carb inlet lien and it restarts.

I can drive it, and it stays running, it accelerates and seems normal. I guess I am pretty much out of ideas to diagnose, so I will plan on taking it into a shop.

Joel

 

You may have something in your fuel tank that occluding the outlet

 

Is it purely a function of the angle at which the truck sits? If so, have you checked the float height?

 

Thanks - that is what I am thinking as well. I guess I will look into droping the tank.

Joel

 

Perhaps the float in the carb?

David

 

Good thinking fmc, I hadn't thought of that!

 

Well Guys, good news I believe I have temporarily fixed the problem... It is a Camper Special with two fuel tanks and a switch valve. The switch valve had been by-passed and connected directly to the input line. I switched and directly connected the rear tank the the input line, and started, and immediately the fuel pressure went up, truck idles and runs great now.

I guess I will have to remove the front tank to see what the issue is, but at least the truck runs reliably now.

Thanks for all of the help.

 

For reference, here is the sequence I went through on my '78 F250 - originally my father in law's, now mine.

- clogged filters and shutting down
- observed fuel from front tank very dirty/rusty
- disconnected front tank, bypassed valve and installed extra filter between pump and carb
- ran OK for a while
- scrapped front tank
- started shutting down again later on
- replaced fuel pump, still a problem
- replaced rear tank which was pretty rough, still a problem,
- replaced old collapsing under suction rubber fuel lines, fixed!

Lessons learned? 1) Extra filters may help "nurse" a dirty/rusty tank but are not a long term fix. 2) always replace all rubber lines if slightly suspect 3) I installed a 19 gallon tank, wish it was a 38 gallon version. Next upgrade is 38 gallon. 4) With attention, these trucks can be very reliable and useful.. why I need the 38 gallon tank.