Wont start.

My uncle just bought a '90 XJ. It has ran great for a week, Sunday and took it out to play in the dirt a little and everything was fine. He parked it, and Monday moring came around and it wouldnt start. It cranks and cranks and cranks but no start. I just got off the phone with him and he says it has no spark. Any ideas?

BTW, is a '90 XJ with the 4.0L a Renix? Or is that when they did the switch to the H.O.?

90 is Renix. Search crank position sensor.

Unplug the crank position sensor, hook an ac voltmeter to the two prongs and crank the engine. You should have between .4 and .5 volts. If less than .25 volts, the car will only start intermitently. Next check the cps resistance, should be about 225 ohms, if thats ok, use a long screw driver resting on the shoulder of the cps, and tap it with a hammer, to bend/deflect it toward the tone ring. Be carefull, if you bend it to much and it hits the tone ring, the cps will be ruined. Keep doing this a tap at a time till you get .4to .5 ac volts, that's what the ecu requires to trigger igniton and fuel injection. If the cps is working ok, check fuel pressure.