hi my 1994 4.0lohv will not start up. i just changed the rocker arms, pushrods, and also did the timing chain and gears because it was tapping from the tensioner being weak. the motor ran good for two days then lost power and shut off. know it cranks over and acts like it wants to start then it starts to back fire either through the intake or out the exhaust. Any ideas would be very apreciated. i also changed the fuel pump do to the pressure wasnt where it should be on static pressure. i changed the cam sensor too.

 

Welcome to the forum

First thing to do when any engine cranks but doesn't start, is the 50/50 test
Spray fuel into the intake and crank engine
If it starts and dies then you have a fuel delivery issue
If it doesn't start then you have a Spark, or maybe a compression issue

So 50/50 fuel or spark, a quick way to get you on the right path

One thing about "new" parts
New used to mean tested and working
New now means you test it for us and we will warranty it if it doesn't work

So "new" parts are not working parts until they are, lol

My bet would be new fuel pump is no longer working, common occurrence for 3rd party pumps, if its a Motorcraft pump then never mind, they work, lol, but cost an arm and a leg
When you turn on the key you should HEAR the fuel pump "HUMMMMM" from the gas tank for 2 seconds, it only runs for 2 seconds, but it does this EACH TIME you turn the key from off to on, so repeat as much as you need, to either HEAR the pump or confirm you do not hear the pump