Well, I have never EVER recommended that anyone buy anything but genuine AC Delco O2 Sensors when it comes to GM vehicles. Then I go cheap because I really didn't have the money to buy the AC Delco parts. $60 later (for 2 upstream sensors) and my Bravada was sittin pretty. I jumped 3 mpg and life was good.

That was until today. Driving to a fire training exercize and it starts to miss and stumble. Wide Open Throttle (WOT) is fine, but just cruising, it's missing quite a bit. Just before I pull into the fire hall parking lot, the CEL (check engine light) pops up. DAMN IT ALL!!! Anyway, I run the codes and get 2 B1S1 codes for the O2 sensor. Damn things were brand new Borg Warner not even 2 months ago (less than 400 miles on them) and one is bad already. Get this, only had a 30 day warranty... Now I would have spent double to get the AC Delco parts (thanks to a local AC Delco retailer - from a dealer it would have been well over $200 for 2), but I would still be further ahead by now...

Anyway, for those of you that want to know, the AC Delco pn is AFS-105.

Anyway, just had to vent. I cleared the DTCs and will wait to see if they pop back up or not. On the test drive after the clear, all seemed well. I knew it was a sensor problem because after the CEL came on, it ran fine (ie. no missing or anything). That's because it goes to a predetermined fuel map when it has a sensor failure in the fuel delivery system (O2 Sensors, MAP sensor, MAF sensor, TPS sensor and Coolant Temp sensor).

 

I just got my blazer and that was one of the first things I have changed. I used the bosh oem which are the same ones the factory puts on. Make sure to put lots of ati-sieze.

 

Sorry ivannj, but Bosche is the ABSOLUTE WORST O2 sensor for GM vehicles. I stay away from them like they've got the plague. What GM puts on is AC Delco nothing else. The OEM part of the Bosche sensor is the fact that it can plug directly into the wiring harness, unlike their universal O2 sensors which require you to cut the connector off of your old O2 and splice it onto the universal sensor.

Also, lots of antiseize is bad as well. You just need enough to coat the threads on the sensor. Too much and you could end up with antiseize getting into the sensor and ruining it.

 

Also if no anti seize was used on the one you are removing don't get ahead of yourself and jerk on the wrench. You could just break the whole sensor bunge right out of the exhaust pipe as I did to mine. ooopoppps

 

IF you don't have anti-seize and even if you do. I always use a torch to heat the threads up. Helps in removing them a bunch.

And your sure your EGR isn't plugging up? It will also trip the O2 sensor codes.

 

EGR was just off and cleaned shortly after purchasing the truck (about 1500 miles ago). It was clean as a whistle inside (well, clean as a black soot lined whistle... no chunks or excessive buildup). The EGR valve wouldn't cause a lazy response from the sensor. I can graph the O2 sensor outputs (B1S1 vs B2S1). Comparing side to side, one side is cycling around twice as fast as the other. A faulty EGR valve should impact both of them the same. Plus, I have checked the EGR valve desired position as commanded by the PCM and the actual position as the sensor in the valve states and they are spot on all the time. If it was hanging open, the actual position would be different.

As with everytime that I replace O2 sensors, I heat the bung (as stated above) with a torch. Won't have to do that this time when I replace them as they were antiseized well and just off less than 2 months ago.

 

I would have gladly heated mine too but I was at a backwoods part store in the middle of nowhere at night.

 

Sounds like you got it covered. Hope those new O2 sensors fix your problem.


I know all about making repairs in the middle of now-where, coldest day of the year, or worst snow storm in years.

 

I can't believe you think bosh is a bad brand but you also think Royal purple is bad too lol. Just busting *****.

 

bosch will do the job just as well as any other but it's the lifespan where they fall short to delco and i wouldn't use wells as i have had a few of them were the screen cap thing that is actually on the inside of your pipe has fallen off. It's a funny thing when you take your o2 out to find somethings missing.