I have an 88 Cherokee, 4.0 litre straight 6. it Wont start, went through 2 coils, put a new one on and it ran for about 2 days. Went out this morning and it wont start. Tested the coil and it read about 10 -11 volts, put a different one on, same reading. Cannot figure this out.

 

Crank positsioning sensor. Thats what I'm thing or you tps.

 

Yeah we were thinking that it could be one of those i dont think its getting spark though, not really sure im kinda stuck.

 

cap/rotor... good output at bat... well grounded...

 

You MUST determine what you are missing:

Fuel + Spark + Compression + Air = Start

Assuming compression and air are there, your focus is fuel and spark.

Start with spark.

Pull a spark plug, keep it attached to the spark plug, place the plug electrode near a good engine ground. Have a buddy crank the engine while you watch. You are looking for a strong, blue, snapping spark. Yellow/orange/white indicates a weak spark which may not be strong enough to start the engine.

Spark check our nice and blue? Move onto fuel delivery.

Spray a small amount of starting fluid into the intake. If the engine starts andr runs momentarily, you have verified a FUEL DELIVERY problem.

You need to isolate this and the above tips will help you do this. Don't guess. TEST.

BTW, the test for coils is for primary and secondary resistances. Voltage test is absolutely inconclusive. Look elsewhere if you've replaced the coil. But to properly test, you need to get a manual (buy one) and follow the procedure for testing it. Don't forget about the ignition control module, located underneath your coil.