Jeep will not start, spark, no gauges work

For starters, have to get the battery back up to snuff.

Do I understand this is cranking, just not starting?

Yes that is correct. The starter will turn over but it will not fire. My neighbor and I have looked through the service manual and have narrowed it down to the cars computer system. Everything points to this. Yes I charged the battery back up.

Check the main power relays.Sounds like power isnt making it to the ignition switch or your dash would power up.The PCM doesnt keep the dash from working

Beware of service manuals, they lie sometimes. :shock: Sounds paranoid? Recommend a computer because the flow charts says, " If all tests are good, replace PCM", and you do and it doesn't work :evil: , you go back to square one :roll:

It would be good to make sure the most current software is up to date in the PCM. While it may be a bad pcm, don't jump to quick. We have rarely replaced them. Carefully check the connectors and wiring for damage and continuity.

While it is convenient to try to link all problems together, it can make you disregard somthing because it doesn't fit the way you want it to. I would treat them as separate problems first and go after fixing the dlc or the ignition system. How old are the cap and rotor? Did you pull it and look? May be a bad coil.

I did check the PDS. All fuses are good. There are relays that are interchangable and nothing changes the problem. I thought it was the ignition coil but that has nothing to do with the gauges on the panel. Not all the gauges are not working. The ones that do not work are only
Oil pressure
Temp
Gas
Voltage
Everything else works on the dash
I agree when you say not to believe everything I read in the manual. But all those gauges run through the PCM, along with the on board diagnosis system which my Actron will not read and comes up with a linking error. Also if I need to or decide to change the PCM. Does it have to be a new one and does the dealership have to reboot the system. Or can I purchase a used one and just install it?
Thanks!!!!
Have not looked at cap and roters but would that effect the gauges?

Just to re-iterate:
While it is convenient to try to link all problems together, it can make you disregard somthing because it doesn't fit the way you want it to. I would treat them as separate problems first and go after fixing the dlc or the ignition system.

Last time I replaced a PCM in a vehicle like yours there were about 25 different possible choices from the dealer, it was very specific. Call the dealer with your vin. You can try a parts store to see if they list it, but I wouldn't get a used one, it's just asking for a Frankenstein.

I do not want toact dumb. But what is the DLC?

Don't ever feel that way. :)

Data
Link
Connector

Every day, every tech faces a new unknown. Only arrogance of ego will keep them from improving 8)

you may have more than one problem.To narrow it down this is what I suggest:
Check the coil for spark , if there is no spark,the ignition systen could have problem.
if there is spark at the coil, check for crack distributor cap, carbon traks in the rotor, broken rotor,deffective or disconnected coil-to distributor high tension wire, badly retarded or avance ignition timing....

The computer needs to have power and ground. A fast way to check that is the way you did, hooking it up to a scan tool, but couldn't communicate serial data while the engine was cranking.I agree with you that the computer may be dead but give more chances and try like in old days. :|
In the 1980s , technicians used a voltmeter to test reference voltage while cranking the engine or with the key turned to engine off.To do this,they disconnected the TP sensor and mesure the reference voltage wire and the ground with a digital voltmeter.if the voltmeter showed reference voltage, the computer wasn't dead. The procedure work fine except you need to know which wires to test and you need to understand that a code for TP sensor would be genrated as result of the test.

good luck :wink: