Truck won't stay cranked.

[MJ_Trav]

I was headed to school this mornin and it randomly started spittin and died. Now it'll start but won't run no more than a few seconds. I pulled it home and replaced the fuel filter and pressure regulator, and the fuel pump was replaced a few months back, but it still won't run. Any suggestions? BTW it's the 4.0.

[tbrand]

Will it start at all? Or just crank and no start?

 

Edit: Ha, helps if I read the post.

 

When was the last time you had a tune-up?

[HOrnbrod]

Have you checked the fuel pressure at the rail port?

[Geonovast]

Jump the ballast resistor and see if it'll stay running. It's a very common culprit for a start -> run a few seconds -> die scenario.

[MJ_Trav]

I did a full tune up about two weeks ago. It's definitely getting fire. I haven't checked the exact fuel pressure with a gauge but i bumped the ignition a few times with the regulator off and it was shootin out pretty good, but I'm no mechanic thats why I'm on here lol

 

oh and what and where exactly is a ballast resistor.... I'm a newbie?

[Geonovast]

Ballast Resistor is a piece of porcelain mounted on the inside of the driver's fender. It has two wires running to it, which can easily be jumped together.

 

Power to the pump is run through the resistor after start up. If the resistor is bad(open), then as soon as the startup process is done, it will switch to it, and the pump will quit.

 

If your truck is an early 87, it's possible it won't have one, and therefore that won't be the problem.