Hi
I'm new to this so please bear with me.
I have a 93 F-250 with a 351 and C-6 transmission. The truck will not start all the time. Seems it's worse after I've run it and try to start it up again right away. If I let it sit, it was starting but today it decided not to start at all. I checked the spark at the coil and that was good. I pushed in on the valve on the fuel rail and there was just a small amount of fuel/pressure.(this was at the point it would not start) Someone banged on the bottom of the fuel tank while i turned it over and it started. Fuel Pump? It seams to have good pressure when its running (I don't have a gauge) I drove a few miles and turned it off and again it would not start. I checked the pressure at the rail again and there was little. After waiting about 10 mins it started again, Any help / advice would be greatly appreciated.

 

sounds like a fuel pressure regulator to me. when it doesn't want to start, cycle the key a couple of times and see if it starts right up.

 

Welcome to FTE

Can you here the pump cycle?

When it does start is there alot of smoke?

Does it smell like fuel when it won't start?

 

I did just that, I could hear the pump go on for a couple seconds and i thought by cycling on and off it might build enough preasure and start but it did not start. One other thing i forgot to mention, I put a fuel preasure guage on the line after the filter at the frame and the first time I turned on the key it only went to about 10 lbs, it incresed every time i cycled the key but it pegged the gauge as it was a low preasure guage.

 

Yes I can Hear the pump cycle
No smoke when it does start but it has been idleing rough and my fuel miliage has gone down from about 10 mpg to 7 when pulling a trailer.
And I don't smell fuel.
Thanks for your help.

 

A fuel pressure gauge sure would be helpfull huh?


Next unplug the vacuum line from the fuel pressure regulator, is there fuel in the line? Try to start it, does fuel come out? Will it start with the line unplugged?

 

Ok I'll try that but I can't untill the morning as the truck is sitting in the rain right now. Is the regulator located at the back and center of the motor ?

 

I can't remember for yours, but it's obvious, the only round thing on the fuel rail with a vacuum line.

 

Ok Thanks again for your help.

 

I would say bad fuel pump.

 

I checked the FPR it did not have any fuel in the vac. Line and it would not start with or without the vac. connected. I replaced the FPR and it started once and not again. I just put a new fuel pump in and I can hear it for a second but it still won't start.
Help

 

Just because nobody mentioned it... what about the fuel filter? Does your truck have two fuel pumps.. the in tank low pressure and the high pressure in frame rail? Im not sure what year they switched to an all high pressure system.

 

I just checked the only filter I know of. It's by the frame rail in front of the side tank. This truck has two high pressure fuel pumps one in each tank. The back one has not worked since I got the truck. Any way I can blow through the filter easy enough.
I just tried cycling the key 10 times and it starts I did this 4 times and it starts every time. It will not start if I cycle it less than 10 times. ??
I sure need to get this figured out. I have some jobs about 300 miles from here but I cant go that far and get stuck. I was going tommorow but that doesn't look so good.
Thanks for your help.

 

Wow, that was weird. I have a 93 f250, 351 e4od and just replaced the pump and regulator today and only get 30 lbs when running. What is it suppose to be? It smokes when it first starts and plugs are white

 

Race4Fun,

You really need to buy or rent a fuel pressure gauge so you can see what is going on. New pump or not sounds like it is not up to the task, test it at the fuel rail and find out.

BearFootCustom,

You really should start a thread of your own outlining your problems in detail.