Running poorly/misfiring, code 33

[JeepsAndGuns]

I have not changed anything in the tune, so unless it reprogrammed itself, it should still be set for closed loop. Plus it was working fine before the issues all started.
I'm thinking all the time I have spent trying to diagnose the issue and it running rich and dumping fuel into the exhaust, then setting for a few weeks between times running, has probably killed the sensor. I know raw fuel is not good for them.
I am going ahead and ordering a new sensor anyways, they are not very expensive, but will double check the power, ground, and sensor wire in the meantime.

I found a good price on the sensor on ebay for $14.99 with free shipping.
Looks like it fits several chevy and GM vehicles. I went ahead and ordered two, to have one as a spare.
https://www.ebay.com/itm/325453630014
Not sure if anyone else has a vehicle that uses that style, but figured if you did, here is a decent price on them.
NTK 21003 is the part number.

[1project2many]

I have not changed anything in the tune, so unless it reprogrammed itself, it should still be set for closed loop. Plus it was working fine before the issues all started.

It's happened to me! It's rare, but it's worth checking your prom to see if it matches your calibration.

Not sure if anyone else has a vehicle that uses that style, but figured if you did, here is a decent price on them.

That's a crazy low price. Hopefully it's the real deal.

[MO LS Noobie]

Has the new sensor arrived and have you installed it? Interested in how all of this plays out.

[mecanicus]

according to the second post of this thread:http://www.gearhead-efi.com/Fuel-Inj...6197427+wiring
i would check the ground connection of the lambda heater circuit.As well it should be possible to attach a four wire lambda probe by connecting the sensor curcuit ground to the ecu ground.I would prefere this.

[JeepsAndGuns]

Sorry for the late response. Weather has not been on my side. Seems like it has been raining here every weekend, the only time I have to work on it.

I checked for proper power and ground to the sensor and it was good. I checked the wire between it and the ecu and it was good.
I got the new sensor. While it the connector looked like the same weatherpack connector, it would not plug in. Turns out the little tabs around the terminals are slightly different. So no idea what the o2 sensor was from that I was running.
So I just simply depinned the old connector and used it on the new sensor. The pinout was the same.
Hooked it up and tested it.
It fired up and ran fine, but the AFR was still not adjusting. I hook up the computer and the value for the o2 sensor was still stuck at 451.
I pulled the memcal, read it, compared it and everything was right. I double checked the signal wire and it was still testing good.
In some frustration, I grabbed my spare ecu and plugged it up, and it now works! O2 sensor voltage was now swinging and the AFR was now adjusting.
I took it for a drive and it ran great, just like it always has. AFR was normal and it seemed like everything was back to normal.
So my guess was a bad pickup coil originally, then a mismatch of ignition coil and pickup coil when I tried swapping in the junkyard parts. Then the o2 sensor issue, who knows?

So I unbolt the old ecu from the dash and install the spare one. I park it for the day, thinking all was well again.

I go out the next day and me and the misses are going to go out for lunch. I decide to take the Jeep since it was finally fixed.
I get it in, it fires up just fine, but then sounds a little off. As soon as I start driving it, it is back to the original issue of missfiring like crazy, not on any 1 cylinder, and feeling like it is only hitting on half the cylinders.

I feel like I have just made a 5 month long complete circle right back to where I started. I just want to bang my head against the wall. I feel like I complete failure of a mechanic.

[steveo]

oh man we have all been there. it took me 6 months one time to fix a car where the brakes didn't work worth a crap, and it ran super lean
after replacing every single brake component, the maf and map sensor, and resealing the intake manifold chasing a phantom vacuum leak, i found a hole in the *(#$t brake booster
why don't you take a break and work on the WJ? i have one of those man it's my favorite side project

[MO LS Noobie]

I also feel your pain, it is frustrating. I also agree on stepping back from and playing with a fun project to clear your mind.

Then I would start over as if it were a new problem. Since it ran good with this combination for a little while I would first check the feedback side of the system, the oxygen sensor. Try unplugging it, doing a hard reset on the ECM, then start it up and see what happens. This should put it in open loop and if your base programming and wiring is mostly correct it should run pretty good. If not you are chasing a ghost can be difficult to find. It runs good you are looking at something in the feedback either the wiring or your new oxygen sensors.

Remove the fan belt, hard reset, then retest. This will eliminate alternator AC voltage and, believe it or not, problems with static electricity building up the belt itself (I have only seen this issue one time in 40 years being a professional mechanic).

You could have a bad sensor failing when hot, ie. CTS, TPS, or even PCM. Test, don't just replace. I have seen a lot of new parts, counterfeit factory parts, and even new factory parts are bad right out of the box. Remember "NEW" means Never Ever Worked.

If it still runs poorly, I would then look at the wiring, doing a load test on each individual wire, since it seemed to run okay until you mounted the PCM. Wires can pass an ohmmeter test and still not be able to carry the amps necessary to do their job. I use a regular halogen headlights bulb (5 amps) that I have wires attached to it to check small circuits up to 16 gauge wire.. DISCONNECT PCM. Disconnect both ends of the circuit you are working on, this includes every connection that branches off of the circuit. One lead goes to negative battery terminal and the other goes to one end of the circuit you are testing. You then take the other end of the wire and touch it to the positive battery terminal. It should light up the headlight bulb brightly. Repeat on the other branches of the same circuit.

If any circuit fails the above test, then you're going to have to inspect the harness going as far as stripping off the loom and tape and checking each individual wire physically, even tugging on the wire, I have seen the conductor broken inside the insulation.

Good luck, Jeff

[dave w]

I'm thinking that swapping the ECM is a clue to what is happening.

Something electrical is back-feeding the ECM to cause the problem? Possibly a voltage spike?

I'm always suspect of old ECM / Engine wiring, because the copper will corrode inside the insulation.

Possibly try installing another ECM / Engine harness. Send me a PM, I have a loaner harness (deposit required).