Cranks no start

[Myles Cyncora]

Hey everyone

I know I've posted on here before about the same truck and issue. 

I have been trying to get an 89 MJ  long bed with the 2.5L and only 81k kms running after sitting for many years. When I first got it, it had a busted steering column as if someone tried to steal it at some point. So I swap in an 88 MJ steering  column that had command start, I also swapped the Throttle Position Sensor. Just by chance the 89 started right up on it's own tank and original pump. That was last summer and now it hasn't run on it's own since. I've got a brand new tank and pump from my other 87 MJ and a brand new fuel filter under it right now. I've swapped injectors around between the 3 of them. After all this it still only cranks and no start unless it is fed by a bottle of gas directly into the throttle buf instantly dies when it the bottle is taken away. The injector IS getting gas I guess not enough, I'm completely out of ideas now. Any ideas and advice will be appreciated unless someone says just 4.0L swap it then no thank you. 

[MiNi Beast]

have you verified power to the fuel pump? have a ballast resistor on the fender? have you changed the fuel filter? do you get fuel at the rail? do your hear the fuel pump turn on?   

[War_Pony89]

Having just dealt with crappy running truck, Like the guys told me, check your grounds and get a gauge on the fuel rail. I found mine was only pushing 21 psi, would run but bad. Ground cleaned, gapped pugs, new rotor, fuel filter purrs like a kitten now.  From sounds of it fuel pressure is my guess, since runs once you primed it.

[eaglescout526]

6 minutes ago, War_Pony89 said:

. I found mine was only pushing 21 psi, would run but bad

This. While it’s great to check the 2.5L system regulates it to 15psi at the throttle body. 
 

I would start doing an electrical diag with the fuel system. 

[scaleless]

Right, might as well check and clean up your fuel pump ground, which is behind the driver's side tail light.  Remove the tail light assembly and it'll be right there.  You clearly have a fuel issue, so if that doesn't improve the issue I would rent a fuel pressure tester from a local auto parts store and give it a check.