That would do it, except wasn't it running up to this point? Did it just stop, and not restart?

 

All fuses and relays new.....

 

So, let's see If I understand this. You get in the car, and turn the key to on. You don't hear the fuel pump spin up to pressure, you get no 12v to the coil, but all the rest of the dash comes to life. No fuel pressure at the fuel rail. The radio works, all that. You turn the key, the motor cranks, but you get no spark.

If that's correct, it's not the cps. If it were, you would get fuel pump pressure and 12v to the coil, but you would get no spark because the sensor would not signal the cpu the position of the crankshaft for timing. With the key, on you should get coil and fuel pump voltage.
I don't have a good wiring diagram for the xj, but I believe the ignition and fuel system are protected by a common fusible link rather than fuses. That could be the trouble. It could also be something as simple as a corroded connector.
Honestly, it's not likely its the CPU. I'll check around and see if I can find a good wiring diagram.
Do you have a volt/ohm meter?

 

Here is a link to a great wiring diagram. According to this, the fuel pump is fused. If you've really changed all the fuses, below the dash and in the distributuin block/relay center, pull the fuel pump relay and see if any of the terminal sockets have 12v. If yes, turn the key to on. There should be power at 2 terminals. If not, then your ignition switch is bad.

http://www.scribd.com/mobile/documen...u51zk3yj1exksn

 

No power to coil or fuel. No pressure in the rail. No radio power. I believe dash powers up.

 

still betting that it has something to do with his lack of grounds. OP, was it running before?

 

X2

 

My buddy said his brother drove it one day parked it and never ran after that. There's water marks up to the ecu.

 

And when you jump power to the 12v side of the coil, you do or do not get fuel pump and pressure at the rail?

 

and later OP writes

This will not be a simple, tighten the grounds and replace a sensor troubleshooting.

For a 1991 in this condition I would;
1. replace the distributer or bolt it in correctly
2. replace the ECU/ECM, the brain under the hood, (a loaner would help)
3. disconnect all sensors EXCEPT the crank sensor and distributer sensor
4. start it up trying starter fluid

 

Lotta money for parts there.

My guess is the auto shutdown relay is tripped, cutting power to the coil, fuel pump and injectors. If he backfeeds power to the fuel pump when he jumps the coil, that proves it. The question is why.
Could be a rusty pin connection on the ecu, corroded ignition switch connection giving poor voltage, could be a corroded connection to the the relay itself, could be a chafed wire. You can screw with the dizzy all you want. No power to the coil and fuel pump and it's not going to start. The auto shutdown controls those. Just for grins I went out to my rig and pulled the crank position sensor plug. Still got fuel pump.

 

OK I tried all the BS tests like unplugging map censor plugging it back in. Replacing the coil. Making sure it wasn't the neutral safety switch. Idk what else. But when I jump wire on the 6 prong plug next to the ecu that someone told me is for the dealership to check codes. Fuel rail fuel pump and to the coil but no power out to the distributor. Ecu could cause all of this. I guess also bad grounds. Or like he said it could be the safety shut down switch which I guess is in the back of the jeep? But I haven't checked that yet

 

Where is and how do I reset the safety switch?

 

The switch in the back you're talking about is only on models with factory anti-theft systems. Shuts down fuel if yhe truck is started by some means it senses isn't proper, like hot wiring. Don't think you have one.

You're problem is the shut down relay that kills fuel and spark if the key is turned off, or the engine quits because the ecu senses an anomaly in the ignition system when the truck is running. It's there to prevent fires and such in case of an accident.

The relay is in the relay center, all of which you say you've replaced. If it were my truck, I would start by cleaning all the pin connectors to the ecu, ignition switch and the relay itself. If no joy there, I would start checking voltages at the pin connectors powering the ecu and the shut down relay, being sure they are up to spec. If not, you've got a corroded wire or connection midstream. And yeah, it could be bad grounds, or a corroded ground wire /lug connection.

The wiring diagram I posted earlier should help you out.

Electrical problems suck, you just need to work through it systematically.

 

OK so its not crank position censor. If I put a ecu in and doesn't fix it wat should I do??..... junk it hahaha