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Yeah this jeep suffers from a bit of DAPO so I wasnt super surprised about the injectors. Ill have to look at them again, but externally it looked like a stock injector, so maybe theyre an updated stock PN?
New leaf packs are pretty much on the bottom of my list of things I want to do, between the possibility of rusty bolts/bushings, spring quality, and money. If it does get to that point I will probly do OME 2" lift.
I found one pack and plate from the green jeep, not sure where the other one is. Im gonna try to cut the mains out and add them to my current leaf and see what happens.
Seems like its settled back into low idle (670) and bad MPG... Tempted to fire the parts cannon and throw a TPS and MAP at it. I also need to check cam sync but Im not sure if it actually causes any symptoms... Dont really want to spend 200 bucks on obd2 stuff for my mt2500 so hopefully I can find someone with a scanner.
Im also annoyed at the way the trans shifts, but Im pretty sure thats just the way it is. Have I mentioned I HATE 97+ cherokees?
Have you tried a bluetooth OBD2 adapter and Torque or another phone app? Way less than $200 and much nicer to use than a standard scanner. But maybe you are looking for a dealer-level scanner?
Yeah I have a Bluetooth adapter and a cheap handheld scanner, I don't really like torque but haven't tried anything else. AFAIK there are very few scanners that will show the cam sync function and the mt2500 is one of them, it also has bidirectional control. I decided I didn't want to rely on using someone else's scanner so I bought the stuff I needed. After I set the sync I'll put it under the seat and forget about it until next time I need it just like I always did with my renix jeep.
Well, since the jeep has been drivable I haven't really got much accomplished.
About 100 bucks in car washes
Cleaned throttle body. It was super dirty, and I found a split in the gasket, but didnt notice any difference after.
Bought a box of used OEM sensors, throttle body, and coil rail for 50 bucks. Just to keep under the seat for spares. Stopped for some glamour shots on the way.
Finally changed rear shocks. It was so bouncy I think it could make someone seasick lol
These Chinesium flag nuts worked fine. Monroe restore shocks are pretty damn stiff but I guess Im getting used to them.
We got about 11" of snow, but I had to work that day
So a couple days later I did some urban wheeling and drove around for an hour busting drifts. Jeep did pretty good. Still learning how the 242 works.
Last night:
I fell into some hype on NAXJA and bought an AISIN crank sensor. I am still trying to figure out my weird idle so I changed the crank sensor, and swapped the newish looking aftermarket (?) coil rail for the used OEM rail.
Looks like the CPS that was in it is the newest PN and maybe from 03? I noticed the magnet is way stronger in the OEM sensor. I really hope this doesnt kick me in the *** some time...
Also changed speakers, which turned into a whole disaster of fixing door wiring etc.
Did another drain/fill on the trans fluid.
Got a mile down the road and set a CEL for B1S1 high voltage. Its stuck at 1V. WTAF
Does seem to be idling better, but not sure if its actually fixed, or just from being in open loop.
Still need to do:
Balljoints, hubs (?), CVs (?), driveshaft ujoints, install 2m Radio, Install hf radio (?), ext idle switch, Efan, console vent tube, power outlets, springs, lunchbox, hitch/recovery, front pinion seal.
Well... a good waste of about 7 hours today. Pulled the harness out expecting to find a broken or chafed wire. Ended up finding nothing? Ohmed, beeped, twisted, shook, ohmed between wires, etc and couldn't find any problem. Re loomed and reinstalled, no CEL so far.
Its throwing a code for b1s2 high voltage and b1s2 heater. I havent checked it out yet.
Found that my throttle shaft is kinda loose, thinking if the shaft seals are leaking maybe thats the cause of my weird idle. So I tore my spare TB apart and gonna order bearings. Not sure what to do about the shaft wear, might fill it with jb weld and then file it back down, or just leave it alone.
Not super happy that I nicked the throttle shaft bore in a couple spots, and got a little agressive with the wire brush inside the TB bore, but hopefully itll be ok.
Yeah thats what started this whole disaster lol. I have seen that video posted in a bunch of places but never actually sat down and watched it before I tore the TB apart. Actually still havent watched it. So I was expecting to find Orings in there and when I saw that they were actually bearings with hard nylon seals, I just decided to push the bearings out instead of trying to pick the seals out.
Guess I should actually watch it sometime.
Ive been fighting the CEL again. I must have missed a problem with the harness, I have had a CEL for rear heater and high voltage for a couple weeks now, which I have just been ignoring. It finally threw the same codes for the front sensor and started running like crap. If I pull Fuse 17 for the heaters it will run fine, the sensors seem to work properly, but if I idle too long the sensors will stop reporting and it will drop into open loop. I tried replacing fuse 17 and pulling the rear heater relay, same problem. With the front relay pulled, F17 installed, and the rear relay installed, it seems to be Ok. So maybe a short to sensor ground in the front sensor branch.Trying to track down exactly where the problem is so I can find it next time I pull the harness out. Or maybe I will just buy a new harness if I can find one.
Took it on its first somewhat long trip, 150 miles each way, a tiny bit of 2 tracks and some local driving. It did good. Got 18MPG, was hoping for a little more but there were some hills it downshifted on, and the slow speed driving I did.
Got my 2m radio installed so did some APRS on the way back. Coverage is a little better here than I thought but still kinda spotty.
Still have a bunch of little stuff to do but have just been driving it instead.
Gotta get a radiator put in my car and work on rebuilding my truck.
Last edited by 89Laredo; Apr 27, 2026 at 01:51 PM.
After 2.5 hours crawling around under the jeep last night I THINK I found my oxygen sensor problem.
I had voltage leaking into the sensor circuit, making both sensors stick at 1v. If I pulled the heater fuse or the front sensor relay it would go away. This worked fine for long trips, but as soon as you try to idle they drop back to 1v because theyre not hot enough, and then the jeep runs like crap until it throws a CEL and goes back to open loop.
My guess was that I had voltage leaking from the 12v heater feed into the sensor circuit. I was wrong.
As much as I complain about people using AI, I dont know if I would have found this without GPT. I fed it the 2000 XJ service manual, a list of things I had tried, and a list of symptoms and then followed tests it gave me.Codes/symptoms:
B1S1 high voltage
B1S1 heater circuit malfunction
B1S2 high voltage
B1S2 heater circuit malfunction
Initial isolation:
Pulling Fuse 17 makes the O2 high voltage issue go away and the sensors report normally.
With Fuse 17 installed, pulling the rear/downstream O2 heater relay does not change the symptoms.
With Fuse 17 installed, pulling the front/upstream O2 heater relay makes the high voltage go away.
That pointed toward the front/upstream O2 heater circuit affecting the O2 signal circuit.
Relevant circuit info:
C107 pin 3 = K167 brown/yellow sensor ground
C107 pin 7 = A42 dark green upstream O2 heater feed
Upstream O2 heater circuit was about 5Ω, which seems normal.
Other sensor-side continuity checks looked correct.
With the upstream O2 sensor disconnected, the high voltage issue did not initially go away, so I started looking at the vehicle-side harness instead of assuming the sensor itself was bad.
Relay/C107/PCM C1 tests:
With the upstream O2 sensor plugged in and PCM C1 unplugged, I measured about 5.6kΩ between the front O2 heater relay terminal 87/output side and PCM C1 pin 4.
I then checked C107 Pin 7 to Pin 3, and got 5.6K again
With the upstream O2 sensor unplugged, that same relay 87 to C1 pin 4 path went OL.
With the O2 sensors unplugged and PCM C1 unplugged, C107 pin 7 / A42 upstream heater feed to PCM C1 pin 24 / K41 B1S1 signal was OL.
I again checked C107 pin 7 / A42 upstream heater feed to C107 pin 3 / K167 sensor ground. With the sensor unplugged, that was now OL.
Other heater-feed-to-signal/ground checks with the O2 sensors unplugged and PCM C1 unplugged were also OL. Looking back a couple of these steps were a wild goose chase, apparently while unplugging the sensor I had moved the harness just right for the short to go away.
Key finding:
At the upstream vehicle-side O2 connector, I had about 5.6-5.8kΩ between pin 2 and pin 3.
Pin 2 is Z1 black, heater ground.
Pin 3 is K167 brown/yellow, sensor ground.
Disconnecting C107 did not make the 5.6kΩ go away. Meaning it was in the O2 harness above the transmission.
Wiggling the front O2 wiring made the 5.6kΩ drop out to OL.
Current theory:
There is an intermittent leak/short between the O2 heater ground circuit and sensor ground circuit in the front/upstream O2 vehicle-side harness branch, likely close to the O2 connector. When the front O2 heater relay is energized, current goes through the heater to Z1, then leaks into K167 sensor ground, which biases both O2 sensors high because K167 is shared by both O2 signal circuits.
That would explain why:
Pulling Fuse 17 makes the issue go away.
Pulling the rear O2 heater relay does not help.
Pulling the front O2 heater relay makes the issue go away.
The high voltage affects both B1S1 and B1S2.
The fault changes when the front O2 wiring is moved.
Next step:
Open the loom near the front/upstream O2 connector and inspect the black Z1 wire and brown/yellow K167 wire for melted insulation, chafing, corrosion, moisture, or connector damage.
I think I will buy some wire and connectors (if I can find them), and rebuild the harness up to C107.
