my mechanic needs help

If anyone knows of a reputable mechanic that is familiar with the 4 litre i6 engines would they be willing to speak with my mechanic about mine? he is at a loss, we have compression, spark, and fuel. it is not a crankshaft position sensor (newly replaced), not a fuel pump, not neutral safety switch, not grounds, not battery (new one before rebuild), not fuses, etc.

i have a 94 xj with a newly rebuilt engine that is cranking but not starting.

any help would be appreciated

A few things come to mind, check and see if the power in for the injectors is getting power while cranking?
Make sure your fuel pressure is holding while you crank it over. The only way to know for sure is a fuel pressure gauge.
And lastly, maybe the distributor was installed incorrectly. It is possible to install it with the rotor in any old position, only one of which is correct.

The first thing to come to mind is the distributor is installed
out of phase with the crankshaft. The engine must be on the
compression stroke of #1 cyl, rather than exhaust stroke.

Installing a distributor will take some trial and error, first, top dead center cylinder one or cylinder one top of the compression stroke and timing mark aligned to zero. Use a long screwdriver and align the oil pump notch to the bottom distributor blade as best you can. The distributor gears are helically cut so the rotor will rotate some when dropping the distributor into the well and the distributor will fall into the oil pump slot (hopefully), which may take a few tries. The Rotor should align with the cam sensor wires where they enter the side of the distributor housing.

Runnin'OnEmpty said:

The first thing to come to mind is the distributor is installed
out of phase with the crankshaft. The engine must be on the
compression stroke of #1 cyl, rather than exhaust stroke.

Click to expand...

The plug wires also need to be in the correct place. There are many incorrect drawings out there, including the Haynes drawing. Here is a good reference for clocking the distributor and showing the correct firing order. http://cruiser54.com/?p=68

Wouldn't disagree with any of those suggestions/comments - but none of them are XJ/Jeep 4.0 specific; all basic stuff which any self-respecting mechanic would know, checked & eliminated.

One thing I'd check is the relays, as I've learned to my cost. Swap the fan & starter relays, takes minutes, costs nothing & might be all that is wrong.

thanks to all, he finally got it running. the distributor was installed incorrectly. a huge relief to all of us.

Runnin'OnEmpty said:

The first thing to come to mind is the distributor is installed
out of phase with the crankshaft. The engine must be on the
compression stroke of #1 cyl, rather than exhaust stroke.

Click to expand...

Running on empty speaks -- as always -- with great wisdom. That's the first place I would look -- and I might admit -- have looked.

Just realised the full significance of the thread title: "my mechanic needs help" - he surely does!

Still, the important thing, at least for OP, is that he got there in the end - & the problem's sorted.