engine spins over no crank
 

i have a 99 cherokee that a "friend who knows everything" changed out the engine for me. it cranked before in the 96 but not now in the 99. i have no power from the coil. does the plug to the coil supposed to have power when cranking and are there fuses that control this. please help.as

My uncle did an engine swap in a xj and got the firing order wrong so the engine did not crank. Just an idea.

spins no crank
 

i spoke with a tech at my local dealership and he steered me towards the crankshaft position sensor and connector. apparently if the computer sees no cps its as dumb as a rock. sure enuf the wire was cut. repaired the wire and check eng light came back on. still no crank but i am making progress. the tech was more than helpful, i havent gone back yet as i am reluctant to bother these guys for free information without some previous effort on my part to solve the problem.

The strategy for a no-start is always the same.

Job #1 is to verify spark. Pull a plug, keep it attached to the plug wire, 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.

If spark checks out, spray a small amount of starting fluid into the intake. If the engine starts and runs for a bit using this technique, you have identified a fuel delivery problem.

The above two procedures take only a few minutes and will help you isolate the "root cause" of your problem.

Good luck and let us know what you find!