cranks good/no start condition

Common failure item on the 4.0 that will cause this is the crank sensor. It is stuck in the bell housing at the rear of the engine and can be a PIA to change depending on how tight the tunnel to transmission clearance is.

I changed it today, still the same.

Okay, test the auto shut down relay if it dies or loses power you lose the spark and the injectors as well as the O2 sensor heaters. It is fed from fuse 6 (always hot) and feeds fuses 16 and 26. Check 6, then turn on the key and see if you get power at 16 and 26.

If all is okay check for power at the dark green w/orange wire at the coil rail and the dark green w/ light green wires at the injectors.

No real trick to checking for spark, pull the coil rail, pull the plugs and just run a jumper wire from a good ground to one plug, then wrap a bare wire from that ground to the other plugs. You just need to make sure the plugs are grounded when you hit the key to test. Once you see spark you put the plugs back in.

Hey Steve, good afternoon..i went out to do those tests, when i pull out #6 ASD fuse it felt really loose and the bottom blades and the inside blade sockets were a little loose and looked burnt/i cleaned them up/ checked for hot (good) went to start/key to on/noticed the check engine light stayed on/plug scanner in and p1389 came up (no ASD relay output voltage at PCM) thanks to you i feel we are getting somewhere. okay Steve whats next step. please when i get my income return i will buy you a ten cups of coffee. thanks for all the help/advice/tests to do so far.

Steve, i forgot to tell you i turned the key on and checked the fuses #16 and #26 no power on top of fuses. i pulled them both checked blade connections. no power/key was on. both fuses/blades/ and inside look clean and tight.

To Steve one more thing, i charged my battery last week,all day on a slow charge,put it back in ,volts were 12.7/12/8. i check this morning and it read 12.3 is it because we tried starting it yesterday after we cleaned the tank/replaced fuel filter/regulator,then tried again after crankshaft senor was put in? Should i charge it again? please let me know. thanks Steve W. And to 2carpros.

Without power from the ASD relay those fuses won't have power. Your description says you will either want to replace that connector or tighten it by gently using a small bladed screwdriver or similar tool to bend it tighter.

The code verifies that power is not making it through the ASD relay. Once that is repaired it should start as the ASD relay powers a LOT of the parts that make it run.

Steve W, i charged up the battery, had it tested/okay/back in jeep/i took out the ASD relay # 38 took it over to Carquest, thank god there across the street,he shook it,it rattled a lot/he opened the cover/then he tested it /open and close like 10 times it hesitated a couple of times,i just said give me one,$6.99/back to Jeep/cleaned and mini filed/ tighten up connections/plugged in ASD relay/ and the jeep started right up....i heard a ticking so i shut it off/got my wife to sit in the jeep and turn the key on and off/while i listened and put my hand on the relays/fuel injectors/solenoids/valves/all clicking like they used to. Started the truck for about fifteen seconds. And it sounds like it's coming from around the crankshaft sensor or down underneath my son put in on Sunday, he said he had a hell of a time getting it out and in/the paper spacer was in place and with the KOEO there is still no power at fuses #16 & #26. please any next steps/advice/help will be very thankful.

Those fuses will not get power KOEO, they are powered only when the ASD relay sends them power.

Ticking may be the censor hitting. They are a bear sometimes, but better to pull it and check for damage than to hope it goes away. It could go away at the same time it shuts the engine off. You might be able to install the original as it may still be okay and it did not hit. But I would check to see what is making the noise.

thanks Steve and to 2carpros.com for all the help/advice/one on one back and forth information it was above and beyond more help I was expecting and more. I called the guy and he will be out on Saturday to remove and replace the sensor. thanks again, brother buzz

No problem, it is what we do. Now if someone would develop a remote mechanic drone.

Keep us informed of your progress. Especially in regards to the noise. I would not be surprised if it was the sensor but confirmation would be good. Oh, if it does turn out that the sensor is hitting, could you see if you can post the part number. I would like to add it to my file of "right part, wrong fit". Thanks.

hey Steve, .2carpros I went to jack up the Jeep and put it on jack stands, so my friend can take out the cks sensor again and locate that noise. up on the transmission cross member I found the hold down bracket for the sensor,he forgot to put it on. how important is this? put it back on? please let me know. thanks

It is important enough that you want it installed. It protects the sensor and keeps it from moving if it gets tapped.

thanks Steve, I will let you know what the noise is when i am done.

Is there a ckp system variation learn procedure or something like that to do after we install it/the auto parts store (carquest) said there might be? if yes/how/where? Help please. thanks, brother buzz

Should not need one. But if you want to do a reset-

Disconnect the positive battery cable and touch it to a ground point for thirty seconds.
Reconnect the cable.
Turn Ignition Switch to ON >NOT START

Another glitch

Turn Headlight “On”
Turn Headlights “Off”
Turn Ignition Switch “Off”

Start engine and drive normally for ten minutes to let the system relearn.
It may idle strange until the relearn is complete.

steve w. c/o 2carpros....the guy can't get back out here to r & r the ckp sensor/ I took out the sensor he put in w/o the bracket on...I took it off/out thru the inside hole/plate that the gear shift lever goes thru/no problem YET/ it was damaged on 1 side of the tip looks like something hitting it/took it back to carquest/No electrical/installed parts refunded/returned...no problem/ got one/back to jeep/took a piece of rod 35"rod wired tied sensor to 1 end/over the back top of tranny and linkages /drop it right in,went inside thru the hole and cut the wire tie/rod fell down/easy no problem/ now I took the bracket &bolt &did it the same way BUT every time I go to start to bolt it in/ the bracket or bolt/or both fall out/off over and over again/hours/2 days now......HELP ME/secrets/how to/advice PLEASE..carquest says to take off tranny linkages and brackets/get 2 or3 extensions and it will be easy/I rather do it your way you tell me to do ........thanks brother buzz now I know why he was cusing up a storm and lefted
off the bracket (forgot it my ass )

I cheat a bit. Visit a place that sells office supplies. Buy a small pack of blu tack type temporary adhesive. It's the stuff they sell to stick up items on walls boards where you want to remove it easily. Sort of like a really sticky gum. Put some on the bracket and some on the bolt and stick them in place. Another handy item for these type jobs are those long handled metal fingered grippers.
And most of us have been there with those type fasteners.....

Last week I got the blu-tac, great stuff, I couldn't afford the tool, so I got a curtain rod/bent it a little / blue -tac together / went over the top back by the tranny cross member / over the linkages / got it over the hole / turned the rod to the right angle and dropped right / I didn't
have extensions, so went back inside to the two holes in the floor / had a long combination bit/screwdriver / went thru the lower hole and it went right in, got my curtain rod, bent it half moon shape / put a string on the end of it,anddragged over the wire/connecter plugged it in / started the jeep
started to take it for a drive / running rough / and check engine light on, pulled back into carport / shut it off, scanner time .....1 dtc PO351 and 1 pending dtc P1391 and I hate to ask you. Please, we have to see this to the end. When my son bought the ckp he also bought a cmp sensor but we didn't put it on.......anything, what is next step, blow it up? brother buzz

P0351 - Ignition coil Primary/Secondary Circuit Malfunction -- Remove the coil rail. Check the connection pieces inside the plug connectors, wipe down the boots and look for carbon tracking. When were the plugs last changed, or at least pulled, cleaned and checked?
Check the wire for any breaks or damage.
This is likely the cause for the rough running as it causes misfires.


P1391 - JEEP - CMP or CKP Signal Intermittent Condition - Check the wires and if you have a different cam sensor keep it in the box. Normally this is a wiring issue, not the sensor.

https://www.youtube.com/watch?v=qpL_0-8DrhE
gives you some tests.