fuel pump changed and still not running

That sounds like the 'very' common bad connection on the CPS of the 4.0 engines. The Crankshaft Position Sensor's plug sits on top of the exhaust manifold and is extremely sensitive to it's connection. They are just computer signal pins and the hot cold cycle affects them. Sometimes you can just unplug it and plug it back and the little scratch pin will make a new contact, but the best is to use a spray contact cleaner. WD40 will work in a pinch, but isn't the best. After cleaning it, I recommend some dielectric grease on the plug's seal skirts to help keep condensation out of it.

But then the gauges not reading strongly implies a failed ground strap. The strap is an open mesh strap that runs from the rear of the engine head up to the firewall. I would check it's connections and give it a squeeze to see if the mesh crumbles. Up here in the salt belt, that failure is more common than the CPS one and the engine will sometimes be able to start by stealing a ground.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

shell wrote:

try cycling the key 4 to 5 times with out cranking it.

Are you sure you have fuel pressure to the rail? You might have a bad ground to the fuel pump. Can you hear the pump?

I had a no start problem after a fuel pump change, after a few days of trying to figure it out a friend dropped by. He took the cover off of the throttle body and held the flap/throttle open, it started instantly. No problems since....Good luck