The upside is that there are really only a few pieces involved in this O2 sensor code, and you've already eliminated one (replaced the sensor, no change).

So the only other possibilities are the wiring or the pcm itself.

I'm still not 100% clear on the results of the multimeter wiring testing as there weren't units or wire functions associated with the numbers you listed from the multimeter test. Can you go through and list each wire with the test you did and the result? IE heater ground wire - backprobed connector from sensor side and measured resistance to battery - terminal. Resistance value was 0.001 ohms. Etc etc.

If the wiring checks out good, you'll have to move on to verifying the pcm itself. But I hesitate to start getting into those steps until we're 100% sure the wiring is good (given all of the other wiring issues). You may have already done this, but its just not obvious to me what I'm looking at with the 3 previous measurements you provided.

 

They were measured as voltage. That wire appears yellow and black
Actually if you run it down its a black and tan wire that goes all the way to the connecter in pic. Havent hsd chance to even pop the hood today working the 12 hr shifts. But i may yonite. Will let know of new info. As of now just one code and its o2 no activity.

 

Thats a problem then. You show you're measuring significant positive voltage on 3 wires, and have 1/2 volt on the signal wire when running, meaning you've got + voltage on 4 out of 4 wires. Given two of the wires are likely grounds and shouldn't have ANY voltage (as theyre supposed to be hooked directly to ground), theres clearly something broken here.

Can you confirm via your wire diagram that the wire functions are: heater +, heater ground, ignition switched +, signal? Can you confirm which voltages are on which wires? Which of the 4 wires go back to the pcm (thinking through next steps for troubleshooting)?

As before, the # of codes is still meaningless at this point. Its being forced to run open loop with no adjustment and isn't driven enough to run through all of the tests (if the pcm coding even allows it to do some of the tests when permanently stuck in open loop mode). Once we get the O2 working properly and get it into closed loop mode / a properly functioning EFI/OBD2 system, you can drive it a bit and set a baseline for what codes we're dealing with.

 

I guess i missed the part about the diagrams. I have nothing but my phone to go from and its alot of zoom in and out. Need a witing diagram for that car i can print and stdy to see where and what im even looking at. Any cheap or free ones you know of? Like to have vaccum and wiring if ar all possible.

 

Side note. Right before i came on here the first time i drove the car to my moms. Its about 8 miles. 3 of those at 40 mph and 5 at 55. It really struggled when running 55 at 40-50 it was fine . Just extra info.

 

The cheapest I know of are the Haynes manuals they sell at Autozone for like $20. Not sure if they have every wire like the big GM sponsored manuals do, but they should at least have core ones like this. Another option is that there seems to be several of the oem manuals available for your year on eBay for cheap (around $20 + shipping for 1 of 3 volumes). If you can figure out which volume is the wiring one (or even just buy all 3) - that would be way better than a haynes.

Given the huge number of electrical issues, I don't see that you'll have a choice but to buy some kind of wiring diagrams if you want to get this back on the road again.

 

Thats not totally unexpected given your situation. Fueling is locked at a single value for every cell, and the engine can only operate at so wide of an AFR range without fueling being adjusted. Given the numerous issues, there will naturally be a range of AFRs experienced depending on conditions at that moment. TBH you're lucky its in a window it can operate in at all.

The most likely reason for struggling given your situation is that AFR is simply going outside of the limits of what the engine can run at. While 14.7:1 is ideal for non WOT (and is what the pcm would be adjusting to hit), cars can usually run from low teens up to 17 or so at low throttle position. Outside of this, you'll tend to start getting misfires (and potentially causing damage, especially with prolonged operation).


Not to be rude, but IMO your best bet at this point is just take it to a mechanic at a bare minimum to diagnose the O2 issue (or even better to fix it). The diagnosis process can't be more than an hour for a real mechanic with the proper tools and diagrams. I really do worry that you're going to end up toasting the engine if you keep going but can't resolve it. The other issues are less worrysome if the engine can at least get back to closed loop control (ie it can measure AFR and adjust fueling as appropriate to compensate).

 

Depending on your library system, you might be able to borrow the shop manual (some have these available). I have heard rumor of people going to the dealership and requesting them. If you want the best service manual you can get, the genuine GM service book is the best. For these cars it is 3 books total. I did an ebay search and plenty of sellers are selling all three (looks like for the full set is about $30 shipped, not a bad investment if you plan to keep this car for any length of time).
https://www.ebay.com/sch/i.html?_nkw...&_ssn=&_sop=15

As for vacuum lines, there are not like old carb'ed cars with a ton of vac lines. These are pretty limited. A line for the HVAC controls, another for the fuel pressure regulator, another for the evap purge solenoid and one for the brake booster. I think that is close, if not all of them.

I second this. Some things are not adding up. On of these O2 sensor wires has to be damaged. Sooner that is solved, the better. It is honestly shocking me the amount of cut or damaged wires you have shared on this car. And really concerning. I have seen where people who swap engines cut the wires instead of disconnecting the connectors. All that does is make more work and problems.