sigsandjeeps

Okay, before I get flamed, I've been up for three days and can't get my jeep to run. The basics:
97 sport
4x4
4.0 liter
AW4
5 inch lift on 31.10.5's
Been running great, until…
Dropped my son off at school. Pulled out to head to the store and 3 blocks later, gave it throttle and it puked and died. No warnings. No CEL.
Checked for spark. Good
Changed the crank sensor.
Tested the pick up coil. Good.
Changed the coil.
Pushed the valve on the rail. No fuel. Changed the fuel pump. Nothing.
Checked the TPS. Good.
Hooked a test light up to an injector. Light stays steady.
I'm lost. It seems like the PCM isn't sending signal to the injectors.
I'm not willing to take my rig to the stealership.
Anyone got another avenue to check? I'm happy to be informed.
FYI, I replaced the cap and rotor as well.
How can I check the PCM to see if it's smoked?
Wife is getting a little butt-hurt now and I'd like to have my rig back.
TIA for all the help.

854x4

Is the fuel pump running? Is it getting power? Find out why you have no fuel pressure and then worry about the injectors. Also does the check engine light come on when you turn the key to the on position?

sigsandjeeps

Yes, there is now fuel to the rail and plenty of pressure. The fuel pump comes on fine and works as designed. I should have made that clearer. Yes the check engine light comes on when turned to on. As do all the idiot lights and then turns off when trying to crank and fire. I have checked the codes with the odo button and there is no codes stored that I can find or see.

Turbo X_J

First, clean all the electrical grounds underhood. Then, find someone with a code scanner, with OBD2 it's the only way (it's all 1997 right, not a mixmaster?). Not flaming ya but just replacing parts rarely fixes it & gets expensive.

854x4

OK so now its narrowed down to the injectors not firing you said you have power to the injectors but it looks like the computer is not grounding them to turn them on and off for some reason. The computer fires the injectors by looking at the crank sensor and cam sensor. Check to make sure you have 5v reference on the tps sensor this will tell if the sensors are shorted somewhere. Also try unhooking the o2 sensor and cranking the motor to see if you get injector pulse.

sigsandjeeps

Okay, I started with grounds. That was step one. I've had 4 XJ's. That's a given. It is a complete 97. As for the TPS, I do have 5 volts there. I checked that one out of concern to begin with.
As for throwing parts at it, the parts I've replaced are standard fails with the Cherokees. Hoping to save some money by throwing parts at something is ridiculous. I'm aware. I'm just trying to kill of the things that would cause the problem to start.
I'll try the o2 sensor tomorrow. After I go to the store and buy beer.
Anything else I should try?

854x4

Check to make sure you also have the 5v reference on the crank and cam sensor all data shows orange wire. Try unhooking both o2 sensors there's one before the cat and one after also try unhooking the vehicle speed sensor its on the transmission. When you unhook the o2 sensors check the harness side wiring to make sure its not melted to the exhaust manifold because on the harness side all the reference wires are bundled together with the o2 wires. Have you tried spraying carb cleaner or staring fluid down the throttle body to see if it wants to start?

nakosd

Did you check your fusebox yet? I don't know what your fusebox looks like so you're gonna have to find the diagram yourself.

There are circuit testers you can get that ground to a battery cable or the frame and all you do is touch the tip to each contact point of the fuse (still plugged in). if the tester lights up for both contacts then the fuse is good, if not then its bad.

sigsandjeeps

I Did do starting fluid. It tried. I replaced the fuel pump there after. No go. I'll check the wiring and pull the o2 wiring. I'll check that stuff in the morning. After "breakfast". Once the jeep is running, I'll talk to someone about my drinking issue. They'll point at the jeep and I'll walk out.

854x4

If none of the stuff I said works then I would say either the camshaft position sensor or the computer but since you could communicate with a code reader and you have spark then the computer is unlikely. Could also be bad wiring connection somewhere in the injector harness or cam sensor harness.

sigsandjeeps

Alright, started raining like hell this morning, but I'm headed to work on the jeep. Here's what I'm doing today;Double check grounds.
Pull o2 sensor harnesses and try starting again.
Start playing with every harness to see if it will fire.
Double check all the work I've done.
I'm going to check the coil again, to verify if the PCM is sending signal to the coil.
If I've missed anything, please let me know.
I guess I will also start looking for a new PCM for this thing as well.

MI_Offroad

Not sure if it's the same as 01, but mine died like that and it was the oil pressure sending unit. It had a cracked housing and when ever the jeep hit a bump it would short out and turn off and sometimes wouldn't restart. Got it started, then started pulling on all the harnesses till it died. Never would of thought a oil pressure sender would kill a motor.

nakosd

there are some crucial fuses in your power distributer, not sure if the 97 has one but my 2000 does. Checking the fuses with a circuit tester is a quick and inexpensive test. Also I don't know what your exact symptoms are if you are able to turn it over or not, but i found the diagram below on this page, has some good info on it.

https://www.cherokeeforum.com/f51/no...nostics-78934/

freegdr

check for codes....

sigsandjeeps

Okay, after all the testing for spark and crank and what not, the starter died. No codes for anything. I replaced the fuel pump and borrowed a known good starter from a friend. The rig fired and after several attempts, it ran. Like crap. Checked the firing order in the dizzy and realized I crossed 2 plug wires. Fired it up and it ran great. Went to start it an hour later and no go. 4 hours later it fired up and drove better than ever. All is good now. Thanks for everyone's help.