I scoured multiple forums for answers before making this post so I'll include everything I did and already checked to help get an accurate answer to my problem.

Vehicle 2004 wj 4.0 selectrac 4x4 automatic.
Running and driving fine before (besides a rough idle here and there but no cel codes)

I put in a new ignition rail (msd, not a no name Amazon special) and the car started for a couple seconds and then stalled out. After that, any further attempt to start it and it just cranks but doesn't start. There is no movement on the rpm gauge when it cranks, there is no skim light on. Only lights on the dash are the cel and the check gauges light. Various codes are thrown but the repeats seem to be p1489 and p1490. Now these codes are obtained through the odometer screen, my code reader doesn't read any of those codes.

I immediately thought I shorted something out so I checked all my wiring. I need to preface this by saying I've already replaced the crankshaft position sensor, camshaft position sensor and spark plugs. I rechecked all of those and the voltage is still reading properly. I hear the fuel pump prime when I turn the key on so it's not that either.

When I check the voltage to the asd and to the wiring of the ignition rail itself, both read 9 volts, even when the car is cranking. The voltage doesn't go to 12 volts and doesn't drop down at all.

Just to test, I put the original ignition rail back on to see if I got a defective replacement and the same thing is happening. What's weird is, I let it sit overnight and when I tried to start it in the morning, it started again for that couple of seconds before stalling and now it's back to just crank and no start.

After everything I checked, I'm down to thinking something shorted in the PCM but if everything is reading properly voltage wise, what's going on where it's not starting suddenly?

The only thing I did was not disconnect the battery before changing the ignition rail. Now if that's what caused the trouble, obviously I'm at fault, I just need to know what to do to fix it. I checked all the fuses and relays and even replaced the asd and PCM relays just for laughs. Nothing has helped.

Looking for help with something else to possibly check. Thanks