1996 suburban with 5.7l have good fuel pressure, sparks at the plugs, cranks with starter fluid but wont crank when i disconnect the crank sensor.

If your saying the starter motor won't crank? Make sure the battery has a full charge and battery connections are all good. Then check the wiring circuits at the starter for voltage and ground. When testing at the starter make sure tranny is in park or neutral and the parking brake is set.

If it cranks good but won't start, have a helper crank it while you visually check for spark at the spark plugs. If spark everywhere, use a gage and check proper fuel pressure, also check fuel injector pulse. Can you check applicable trouble codes? How long since a tune-up?

The crankshaft position sensor is located on the right-side (passenger side) of the engine. At the rear of the engine, behind the starter. You need to remove the starter to remove the crank sensor. Remember to disconnect the battery first. The starter can short against the cross member.

check the fuel pressure and make sure you got the correct pressure

In a 96 Jeep not many sensors are involved. Basically Fuel and spark delivery at right time should start car if your Starter is able to crank the Engine.
If engine is cranking then the battery is Okay. Check Spark directly at the spark plugs and fuel pressure at the fuel rail. You may pull out one spark plug and check spark out of engine.
Try spraying Starting fluid in Air Intake while cranking. If Jeep starts then not enough fuel is being delivered by fuel pump. If you find no spark at plugs then check circuit for starter relay, Crank sensor/cam sensor problems.
A kill switch or bad Alarm system can also cause this problem.
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if the engine will start and run for a second or two then die? check the crank position sensor.

check for spark at the plugs..if you have spark..get some auto mobile starter fluid ..spray some in engine intake.. if engine starts ..you have a fuel deltvery problem..that should narrow your your problem down..your fuel pump might be good..there are other parts in your system that will cause pump not to work.. such as plug fuel filter/pump relay..ecm..fuel pump fuse etc..take it one step at a time..guessing is costly

put a timing light on it. if in time then spray some ether in intake. if tries to run now its a fuel problem. make sure plugs are gapped properly. if you got timing,spark,gas at right pressure, and compression it should run.

There is no simple answer, there are to many variables. If you have access to a scan tool, pulling the codes should help. Without them its back to old school hunt and peck method. At this point we need to narrow down the problem. You need to test for spark.

1. Tag and disconnect the spark plug wires from the spark plugs.
   
2. Remove the spark plugs and install the spark plug wires to each spark plug.
   
3. Ground (do not hold spark plug) the spark plug; check if spark occurs while engine is being cranked.
   

Crank the engine for no more than 2 seconds at a time to prevent flooding the engine with gasoline.
If you have spark, You will want to make sure you have fuel injector pulse, along with fuel pressure. If you have spark ..simply spray some starting fluid in through the air filter and hold the gas pedal to the floor and crank it over while spraying. If it fires up, you know it is fuel related( fuel pump, regulator, or ECM if no injector pulse) . If you have no spark then look at ignition coil connection and trace through to the distributor( if equipped ). The crank shaft sensor has a tendency to fail on these as well. This should give you a few things to test and check to start you on your way to narrowing it down. If you have no spark then look at ignition coil connection for power and trace through to the distributor( if equipped ). If it is DIS( no distributor). It may be the Crank sensor or the ECU. The crank shaft sensor has a tendency to fail on these as well.
The ECU uses the signal sent from the Crank sensor to trigger the spark and fuel injectors. ( make certain you have checked all fuses)

you getting sparks; check the basic from fuse and relay. Its seems like you not getting any fuel by having to give it fuel, check the fuel pump see if it working, you can remove it and connect straight to 12v and do a jump. If the fuel pump is good then it will be the crank sensor, crank sensor turn on the fuel pump as long the engine continue turning over. what crank sensor does it sense the crank/flywheel turning and it send single to the computer than computer send power to the fuel pump. sensor tend to go bad over time and heat exposure; the sensor it fairly cheap to replace.

check your cam or crank sensor,i think your sensor not getting signal