Jeep sat for 4 months and wont start

Hello gents,

I had to be away from the Jeep for 4 months and now it wont start. I charged the battery (which was dead when I got back to the Jeep) and I tried jumping it. It will now crank, which it wouldn't do before but it won't turn over. The charger is also showing about 12.3 volts (on an Optima yellow top that was replaced 2 months before I left).

It has gas in the tank and the schrader valve on the fuel rail shows there is fuel getting to the rail but I did not have a way to test the pressure.

The cap, rotor and wires were replaced about 2 months before I left as well and everything worked fine before I left. I popped the cap off and brushed off the rotor contact and it seemed OK. There were no rats nests in there...

I checked all the fuses under the hood and they all seem fine.

The Jeep was in a garage while I was gone too if that matters at all.

Any ideas or suggestions where to look next?

Thanks for the time!

- Colin

Might try reposting in OEM Tech discussion. more viewers in that one.

Cps possibly. Have you verified you are getting spark? I'd be looking into loose connections or bad gas.

I haven't verified I'm getting spark.

I'll look into the CPS too, thanks.

So I did some google searches on how to test the CPS - I tested the sensor between pin B and C and it showed no resistance which is apparently an indicator of a good sensor.

Unfortunately it still wont turn over.

I threw in another battery a friend had and that didn't help either.

I pulled the coil and tested it for resistance and it tested good as well.

I pulled the wire off the coil that runs to the distributor and grounded it out while attempting to start the Jeep - there was no spark.

SO - I have no spark and my CPS seems to be OK.

I have no idea where to go from here.

Maybe trace the wire going to the ignition coil and see if there is any linked, looses, or chewed wires. And maybe swap the ignition cool for a new one to verify if it's working. I had an issue awhile back, turned out to be the coil.

Will it fire when you spray some starting fluid down its throat?

Bad gas? Started fluid and then some seafoam in the brake booster line should clean up the injectors. I'd siphon off the tank and replace with fresh gas too.

Well - I threw a cam position sensor at it, another coil and cleaned the contacts on the distributor. No dice.

I ran to the local u-pull-it and was lucky enough to find a 97' Cherokee with a matching part number ECU and threw that in and it started right up.

I guess my ECU took a shit while I tried to jump the dead battery.

Thanks for all the help gents!