help jeep died

It just died on the interstate. I did the cps trick,no start. put in spare ecu and coil, no spark. :smoker: said fudge it and hiched a ride to work. got it home and brought the coil and ecu to get checked and they checked out fine, the parts store said it may be the pick up coil, I got and put it in still no spark . gas guage reads full, I had 1/4 tank. volt meter reads 0, battery is fully charged. I'm going to the dealership for a new cps. any ideas. 1990 aw4 4.0

I´d check the yellow wire for power with the ignition in the run position. The large yellow wire running to the igntion control unit (coil) or even at the thermal switch (lower left of the radiator, yellow wire). The volt meter is on the same circuit. The yellow L1 circuit runs from the ignition switch, to most motor controls ECM etc. gauges and others.
Possible the ECM is fused with the gauge cluster, have seen drawings that hinted at this, but have never tested it myself and have seen wiring differences form year to year.
Had mine die twice, once the MAP sensor plug fell out and another the five wire connector behind the relay block was full of water. Haven´t had the CPS, problem yet, but carry a spare.

In addition to 8mud's suggestions, you could check the ignition switch (bottom of the steering column, not at the key)- it has lots of circuits running through it and can produce wacko symptoms when it flakes out. Look for burnt out sections.

On my 1988 had the exact opposite, lock cyl bad and could not shut off, had to kill with the clutch.
check the rod going down the column to make sure it did not fall out if you are checking switch.
I have not had problems on my jeep but on my other chrysler if the map sensor was bad it would turn over but not start, usually they are full of water and can not get any vacumm