The fuel injection and the ignition timing in the 4.0-liter engine in a 1997 Jeep Wrangler is controlled by an onboard computer. This means that you will not need to adjust the timing during regular scheduled maintenance. However, if you remove the distributor for repair or replacement, you will need to install it in the proper orientation to enable the computer to do its job.
Remove the number one (front-most) spark plug. Put your finger in the hole while turning the crankshaft clockwise as viewed from the front, with a breaker bar and socket on the front pulley bolt. When you feel compression on your finger, remove it and replace the spark plug. Locate the TDC mark on the harmonic balancer and continue turning the crankshaft until the TDC mark aligns with the marker on the engine block.
Stand beside the fender nearest the distributor hole and shine a flashlight into the hole. You will see the oil pump drive shaft, which has a slot in the top. Turn the shaft with a long flat-head screwdriver until the slot points to the 11 o'clock position, where 12 o'clock is directly toward the center of the engine.
Install the distributor so that the nose of the rotor points at the number one cylinder. Install and tighten the hold-down clamp and bolt.
Plug in the distributor wiring connector and install the distributor cap.
