Dudes, I'm sorry. I know I've been absent but the reason is multifaceted. The only thing right now that's giving me more of a headache than my truck...is my new house. The house takes on water like a boss and the truck I can't figure out. Since this isn't a home improvement forum and I miss my truck Which has been laid up since the inspection expired in July, I come to you for help.
The truck was throwing codes so i couldn't have it inspected. It was an 1191 or 1193 which is "post cat o2 getting rich/lean signal" so I went after plugs and wires. Kingsbourne 8mm and new plugs gapped properly. That didn't clear the code. So then I replaced the post cat o2's with used guaranteed units from will tillery. I had disconnected the negative lead while doing the service and plugged it back in when I was done. Fired it up and boom....check engine came right back on. I haven't read that code but I'm ASSUMING it's the same one. What else can it be? Can the cats actually be bad? Is there something I can try first? I'm out of ideas and i really miss my truck. Help a brother out.
Miss you all,
Turf

 

Hey I still have that set of O2s you gave me. If you want them back let me know. Sorry to hear about the new place I think everyone in that area is having that same problem. I would get the codes read and see for sure what the problem is.

 

All of the o2's at this point have to be good. Short of doing lrd2's method of reading the voltages at the sensors I'm assuming they're good. Thanks Brian, I appreciate it but I'll just have to find a minute and see what the code it's throwing is. It has to be the same one. I'm gonna see if I can't just find someone to pass me, but I'd still like to resolve this. It's really a stupid stupid issue.

 

With your house get a sump pump.... I hope it didn't ruin a lot of your stuff.

 

It might need to go through a few drive cycles if the CEL was on when you changed them, or have them cleared via scanner then see if the code comes back up. To bad your not a little closer id let you use my scanner. I think the codes for bad cats is P0420 an P0421. Im almost wondering if you have a bad/corroded plug somewhere giving you false readings since your truck eats O2 sensors??? Might be worth taking a look at the ecm plug?

 

My truck def eats o2 sensors. That's a good point. I'll look at that. In the meantime I'll see if my old man has the time to run it over to an autozone and maybe they'll reset it (they say they don't do that any more). Ugh. What a pain. Thanks for the insight bri. I'll keep you all posted.

 

Auto Zone will allow you to borrow the code scanner (you gotta give them your DL/ID card to hold), and you can clear them out yourself in the parking lot. Done it many a time.

 

did you clear the codes between trying the different troubleshooting steps? it wont just go away with fresh parts unless cleared with the tool or taken on a handful of complete (cold motor, warm up, drive X miles, cool down, restart cold the next morning, etc) drive cycles...

 

Ok, first things first - isolate your problem so you know what you are fixing! Buy a scanner that allows you to read real time data. They are cheap, less than $50. It will tell you what the truck/ecu is seeing as opposed to doing a bench test which will only allow you to see what the o2 sensors are putting out. Knowing what the truck is seeing is more useful for troubleshooting.

You will also get the code when the voltage differential is too small across the cat between the up and down stream sensors, even if they are not functioning properly. You will get this code if the upstream sensors are dead too. The upstream ones are the important ones, only they effect engine performance.

Also, if you have one of these scanners you can check out whether the readiness monitors are actually "ready". Do a google search on ODBII and " readiness monitors" for more info. The deal is the readiness monitors are actually the important part of the emissions test, not the MIL or "check engine" light. Actually, the MIL can be off and you will still not pass inspection until the readiness monitors are "ready".

Im sorry to say this, but I went through all the same crap you are going through now and I found only one solution: 4 new (OEM!) sensors and new cats. The cats were a bit cheaper as I welded ones in myself. slightly under $500 for everything, plus a lot of time underneath.

I can tell you this: MY MILEAGE DOUBLED AFTER IT WAS ALL REPLACED. Let me repeat. DOUBLED. Went from less than 9mpg to around 18mpg highway. I'm figuring at $75 a tankful that means conservatively after 14 tanks of gas it will have paid for itself, which means around about Thanksgiving (not all that far away) I start making money, woohoo!

 

i THOUGHT that if i disconnected the battery for over a minute that it cleared the codes as well. The issue with autozone or advance lending out the scanner is that (at least in philadelphia) they stopped doing that at the ones ive been to because people kept stealing them. Gotta love philly! I'll def try and get the got reset the right way. I was trying to save up for a scanguageII anyway, but i really want my truck back. I think im going ot try and see if i can find a station that'll pass me, just so i can get the truck back down here, and then i can start methodically working through the issues. Geek, the upstreams are brand new, im (pretty) sure it's not them. But Brian (longhaul) is right, my truck does MOW through o2's. So maybe i'll have to check that ECM connection. If resetting it with the autozone monitor doesnt work, then i'll try and get it stickered and grab a scangauge and start working through things. the good news is that if it IS bad cats, it gives me an excuse to buy a welder. haha. Thank you guys for your input, i'll keep you posted. (it has sucked to not have my truck with the 13" of rain we got last week)
Best

Turf