NO SPARK AT IGNITION COIL?

My son and I replaced the 4.0 engine in his 2000 Wrangler Sport . It was running when we parked it to swap the engine with a rebuilt. With the new engine it turns over but does not start. There is fuel. There is no fire from the No. 1 plug wire. It was showing No bus on the odometer, fuel gauge, and volt gauge were inoperable. I switched a couple of the relays (ASD and something else) and the no bus went away, gauges started working. I switched the relays back and the "no bus did not return, gauges continued to function. However the engine still turns over, but will not start. It has a new coil pack. There is small relay that is grounded to the block just above the oil filter. The wire kept coming out of the relay plug so I put a new terminal on it and cleaned the ground connection.

I feel like we have not put a wire or connection, something, back like it belongs. Any ideas? Thank you.

It turned out to be the Crank Position Sensor. Upon re-installation of engine, we apparently bumped the CPS wire, partially severing the wire next to the sensor. New sensor and it fired right up. Thank you!

Replaced crank sensor 7 days ago and ran great. We just had a snow storm in CT. And single digit temps. Went out this morning and did not want to turn over. Battery Good, but no spark at ignition coil? I am stumped. Do you guys/ gals have any ideas? I am currently attending Auto Tech. School and I don't want to look like a low grade moron to my class mates. I have done everything I can think of. Please help me.

Changed oil and now no spark in jeep wrangler 98 4.0 motor

One day the vehicle wouldn't start, I am a mechanic on the side for the last ten years, figured it would be no problem. Boy was I wrong.

So here is the deal: Cranks but won't start, no fuel pressure, no spark, no communication with scan tool, gauges aren't responding but they do work when you reset them (hold trip reset and turn key on).

All of my relays check good and have been load tested as well, no problems there. I have verified 12 volts and ground to ECM, continuity between grounds are good as well.

Now here is where it gets weird: 5 volt system?
-I am not getting 5 volts out of the PCM with the key on, only about .25 volts.
-If I unplug the sensors on that circuit I will get .63 volts
-When I turn the key off, I am still getting .33 Volts on the 5 volt circuit when I should be getting 0.

Now I know what you are thinking, easy you have a bad ECM, well it is a re-manufactured one that I just put in there because I was 99% sure it was bad too.

Am I missing something easy? Is the new ECM bad as well? Is there something wrong that fried the ECM and the new one?

Any input would be awesome, this vehicle is my dads and I have countless hours in to testing and diagnosing, I just want it fixed and out of my shop! Thank you!

Yes I checked it at the PCM, as you unplug the sensors on the 5 Volt circuit, the voltage slowly increases, but only to about .6 Volts with key on. Any idea why I would have voltage on the 5 Volt circuit with Key Off?

Also, Could there be any other issues that could be causing the PCM to go bad?

I cut the orange wire (A17) a few inches outside the PCM as to completely isolate the wire from the rest of the circuit and still did not have 5 volts, I am suspecting that the "new" remanunfactured PCM is bad also, but I diagnosed it to that point and a $250.00 ECM didn't fix it. So I am trying to figure out if there is something else I could be missing before I get another replacement and find out it doesn't work either.

I started my Jeep the other morning to let it warm up and when I came back roughly 10 minutes later, it had stalled out. I tried to fire it up again, and nothing.

It will crank all day long but I am not getting any spark and therefore it won't start.

I have a new battery, new distributor cap, new rotor, new plugs, new wires.

The CKP, Crankshaft Position Sensor, was resting on my exhaust manifold and it had melted, so I thought I had my culprit - but no dice.

I replaced it and I still have no spark. I am at a complete loss.

I am not showing a check engine light or any other dummy lights. I have checked all of my fuses - all good.

I switched my relays, and they are all in working order.

It is my daily driver so I desperately need to solve this problem as easily and inexpensively as possible.

Also - The Thing that is really confusing me is that my fuel pump kicks on with the key in the on position, but it does not kick off after a few seconds. It runs constantly.

As far as my gauges - they do not move at all. The odometer shows up, but the fuel gauge doesn't move and neither do any of the other ones.

I have plenty of gas in my tank.

The fuses are good, what next?

The gauges not working are a symptom of the larger issue - not getting spark and the car not starting.

The gauges are getting power - they are not getting the signals to make them function properly.

As far the crankshaft position sensor - I already checked and changed that out for a brand new one, as previously stated.

I've just been fighting this problem for the past 6 months. So I took a chance and replaced the relay and no problems so far I will drive it and report back if I have another problem. Thanks for your help.