You DO NOT need the VSS to fire a 4.0. You DO need to to complete the logic circuit for the AW4, but that is not your problem.
Jeep DID NOT change the sensor or the wiring of the CPS.
1. Make sure you have fuel pressure. I know it sounds stupid, but I have seen worse.
2. Make sure your ground to the computer is good. They get real touchy with a bad ground.
3. Does it try and fire/run for a little bit? It is possible to get the key on power and the constant power crossed so it only runs for a couple of seconds, and there is also the encoded key deal. but it will start/run for 5 seconds or so.
4. The plug end has signal/ground/5v power. You can find the ground and 5v in other plugs on the engine to check to make sure you have a good contact. You can trace the signal wire back to the computer and check the pin there to make sure the signal wire has continuity.
MOST 4.0 problems I have run into involve either a bad splice, bad ground or bad fuel pressure. There is not too much else to mess up.
I really can't emphasize the fuel pressure thing enough - I have burned up three pumps that made the noise/squirted fuel/etc but only made ~20 psi at the rail. 4.0's need at least 30-35psi to run.
Any 91-95 4.0 computer will work for diagnostic purposes.
Good luck,
Gavan
