Truck wont start all of a sudden!

[Jmazda94]

I have a 94' b4000, never had any problems starting it before. I was driving it today then I came home for lunch. When I got in it to go back to work it would not start. It would turn over for a second then die. This happened to my brother who was using it while i was in the field working. When I came back he said it wouldn't start for him, i tried it and it fired right up. So im assuming the problem I saw today is what he was dealing with. I think it might be a fuel pump..i replaced the fuel filter recently hoping that would solve it. Would it be vapor lock? It would keep firing up but then die right away, i would pump the gas petal but nothing..

[Jmazda94]

Starts once in awhile then dies.. no help?

[baddis]

check your fuel pressure on the rail key on engine off then try to start it.

[mazdab40004x4]

I had this problem on my truck. I checked fuel pressure on the rail and found it to be low -- sometimes. If I can actually get it started for more than a second or two, the pressure comes up to normal but getting fuel to the engine to get it going has been a challenge.

Basically I think the fuel pump is on its way out, but I've been able to nurse it for awhile. I replaced the fuel pump relay to be on the safe side and then I changed the filter. I have found that if I turn the key to on and then back off a few times before actually trying to turn it over it builds enough pressure to stay started and then runs fine. For some reason it also seems to start better with half a tank rather than full.

Someday I'll get around to pulling the bed and replacing the pump -- likely when it finally gives up completely. And of course I'll be miles from my house and my tools when it happens

[Jmazda94]

haha, yeah prob me also. I am not looking forward to replacing the pump but that sounds like the problem. Thanks!