i replace the motor in my 98 JGC and it too would not start, but upon putting the motor back in the Jeep i took notice that i may have "bumped" the crank positioning sensor, so i replaced that and it fired right up, im not saying that's definitely your problem given you included no details, but its a possibility, good luck
hard or wont start after and during rain
Does it turn over? Does it have fuel, spark and compression?
no it wont fit cause ive just changed a 1990 jeep Cherokee transmission it had a 1998 jeep grand Cherokee transmission in it it broke the fly wheel and burned the torque converter up
somebody broke or didn't connect the crank sensor
Before going after the relay make sure you have enough freon in the system otherwise a/c compressor wont kick on!!!
Try replacing the camshaft sensor. Sounds exactly like the problem I experienced.
check the neutral safety switch. Mine does the same thing. also you might not have reverse lights.
Could be low battery power. Not enough to start the engine.
on the 4.0 jeep, if it cranks, but wont start, try replacing the crank sensor, located at the top rear of the engine, at the transmission
you flooded it
check the cranckshaft sensor and alarm system
battery is dead, alternator is blown, needs new distributor, blown engine, head gasket is out, could be a number of things, take it in to a mechanic