Hi everyone. This is my first post, and my first Jeep.



I picked up a 1997 Cherokee Sport for $400 that supposedly only needed a starter. I picked up a starter and installed it on the Jeep on the trailer we towed it home on. The key wouldn’t crank the starter, so I was jumping the terminals underneath using a screwdriver. Found later that the neutral safety switch was bad, which is now fixed. Anyways, I cranked it a few times with the screwdriver, and it fired up. It ran pretty well for about 5-10 minutes, and then it just died. No stumble or anything. It’s just like it shut the key off. I was pretty low on fuel, so I added gas, and it registered a ¼ tank on the fuel gauge. I got under the truck and cranked it again, but it has never started again.


Now, I get no fuel, no spark, and the gauges don’t work. I’ve checked all the fuses and relays. I can jumper the fuel pump relay, and the pump will kick on and build pressure. I changed the crank position sensor with a used one from a junk yard as a quick test. It didn’t do anything. I’ve read if the CPS is bad, if you unplug it, the gauges should start working again. I’ve unplugged every sensor under the hood trying to get things to come back, and nothing has worked. I’ve checked for voltage on the orange sensor wires, which I read was supposed to be 5 volts, and I’m only getting 0.4-0.5 volts at each sensor. When I was under the truck changing the CPS, I noticed some loose wires behind the transfer case that were taped together, and when I pulled the tape back, some of them could have been touching each other. There are 4 wires, and the only thing I can think they would have gone to would be the rear oxygen sensor, which I haven’t seen in the exhaust pipe.


I went to a junkyard to look for another computer, and they’re all gone. My OBD scanner pulls a P1694 code, but I don’t get the “NO BUS” on the odometer like others have gotten. I’ve cleaned all the grounds, replaced the battery cables, cleaned the terminals on the distribution block, and had the computer out to look for a bad terminal. The computer is getting 12V to the two terminals described in some of the things I’ve looked thru. I’m wondering if the oxygen sensor leads were touching and burned up my computer? Does anybody have any ideas? I almost started parting it, but I let it sit for a few days, and I’m ready to give it another try. I haven’t even driven it yet, so I don’t know if it will even move. So frustrating.


Thanks,
svorn

 

How long was it sitting before you bought it? If you ran it after and it was almost out of gas then try checking the fuel filter. May be clogged if you're not getting fuel.

Did you check the CPS with a multimeter? There is a continuity test you can do with the 3 pins. I can't remember whats what but I believe if there is continuity between 2 of those pins then it is bad.

 

Thanks for your reply!

It had been sitting for several months. If I jumper the fuel pump relay, it will prime the rail with good pressure, so the pump is good. The computer doesn't seem to be telling it to pump or spark. I did check the crank sensor with a multimeter. I have 3 of them. All of them test good, and none of them make the truck run. I'm just about ready to drop $200 on a computer from Advance Auto. Since all the sensors are lacking voltage, the gauges are caput, and it's not sparking or getting fuel, it seems like my only option left.

Thanks,
svorn

 

Clean ALL of the grounds and replace the POS. and NEG. battery cables.

 

I bought a re-manufactured computer from Advance Auto, and after I turn my core back in, I'll have about $200 into it with a year warranty. The Jeep started the first turn of the key, so that was my problem. Thanks for the help!

I think the oxygen sensor wires taped together must have shorted it out. I haven't ran it more than 3 minutes, so hopefully I can take it for a drive tonight to see if it's even worth keeping.