Indexing the 4.0 distributor
Jeep Cherokee Repair – Motor Problems
The procedure in the factory shop manual is surprising simple:
Use a 3/4 inch wrench to rotate the engine to the zero degree mark on the Damper. This is easier if the electric fan is not in the way. Also, you must ensure that you are on the compression stroke of the engine. One way to ensure this is to watch the motion of the valves and make sure that you are using the mark just after the intake valve closes.
Another note: If your damper is old, this is a good time to make sure it is not twisted by checking that the engine really is at TDC when the damper lines up with the mark.
With the cap on the distributor, scribe a line just to the left on the number one terminal. Transfer this line down onto the metal distributor housing. On the Renix version, it will be near where the wires come out.
Use a screwdriver to set the slot in the oil pump drive to 11 O’Clock.
Now take the distributor cap off. Eyeball the mounting tang over the mounting bolt hole in the block. Pick up the gasket you just dropped and put it back on.
Set the rotor to point to about 4 O’Clock. This will be a bit to the right of your mark. (on the HO distributor, align it with the wire.)
Lower the distributor in to the hole and allow it to engage the cam shaft drive gears. The rotor will turn as the gears engage. When it hits bottom, the rotor should be pointing at the mark you made earlier. If not, try again.
Put the mounting clamp on and tighten the bolt.
From the stories I have heard, the computer will not work if the distributor indexing is off even one gear tooth. By using this procedure, yours will be right. Check off another item from your list of Jeep Cherokee motor problems.