My check engine light is on. I took it to Advance Auto and had them to scan it. They said my O2 sensor had a slow response time or something like that,. But i forgot wich one. My vehicle is a 96 Blazer. Are all the 02 sensors the same on my truck?. i was going to buy one, but i didnt want to pay almost $60 at the part store and figured i can get one alot cheaper online. Also what websit is the best to get one at the best price. Also can a 02 sensor be cleaned?

 

Oxygen sensors react to changes in fuel mixture. They react from lean to rich, and from rich to lean. It is possible for a sensor to have a slow reaction time in either, or both directions. Over time, (mileage) the reaction time naturally slows down. At 100,000 miles they have slowed to the point where fuel mileage suffers, that's why it's recommended to replace them at that mileage. They cannot be cleaned. Most auto parts stores stock them at a reasonable price.

 

My MPG is good, i get around 20mpg driving easy out in the country. I found a crack in one of vacume hoses, and my intake hose was almost torn in half on the bottom side right as it connects the the throttle body. I was told that them problems may have been causeing my 02 sensor to read bad. After fixing them lastnight I did notice a big difference in my throttle response time. Im going to have it checked again to see if that was my problem.

 

While a bad vacuum hose would cause some issues, I'm not sure it would cause your o2 sensor to throw a DTC. If you have over 100k and have never done the sensors you should definitely consider doing them. The downstream one can probably wait, but I'd do the upstream ones at least. If your 96 is the same as my 00 then you will have 2 upstream sensors (before the cat, closer to the engine) and 1 downstream (after the cat) and should be pretty easy to get to and replace. Mine has 99k miles on it and it will occasionally throw the code for a bad sensor, so I'm going to be changing mine soon. You can get to them from under the vehicle, might help to raise the car a bit if you are a big guy like me.

Here are some tips to remember.

1. Borrow the sensor removal tool, it'll make your life a little easier. It's basically just a socket with a slit in it.

2. The sensor will come off better when warm (not hot). Use penetrating lube, but only if you have to. It should come off with fairly little effort. I didn't have to lube the one on my Honda. I'm not sure if these will be different. I recommend SeaFoam Deep Creep if it comes to that.

3. Make sure all oils, greases, fluids, whatever is cleaned from the area, these damage the sensor and you want a nice clean spot for the new sensor.

4. Don't fool around with the new sensor. The tips start to degrade the moment they are exposed to the air. Don't touch them, don't get anything on them. Just remove the protective plastic cover and put it straight into the hole, no messing around.

5. Do both upstreams, if one is bad, the other probably isn't far behind.

6. The car might start a little weird the first time with new sensors, but it'll figure it out, let it idle for about 10 minutes without running any accessories or giving it any throttle. Turn it off.

7. Restart and take it for a drive, if everything else is good on the car you should notice it running a little smoother and should see improved fuel economy.

 

Thanks Pheaton for the info. I didnt know about not letting them be exposed to the air. Im going to have my codes run again tomorrow at the Vocational School I go to. And figure out what sensor it is. Then i'll probably buy one off line cheaper and then do it.

I forgot to ask, but are all 3 of the 02 sensors the same, or do I have to buy a individual sensor for the specific location.

 

I believe there should be 4 sensors.


Only the ones located between the exhaust manifolds and the 'y' in the y-pipe (B1S1 & B2S1) have anything to do with the engine management. The other two are catalyst monitoring only.

They are all the same. AFS105 is the AC Delco PN and I wouldn't recommend anything but AC Delco O2 sensors, a recommendation based on testing I have done on other GM vehicles.

 

I can confirm the Bosch ones are good also. My 2000 Bravada has 3 sensors and yes they are all the same. I got mine off of Amazon and saved some cash.

Your 1996 does in fact have 4 sensors (all the same). 2 upstream and 2 downstream. The downstream ones usually only throw a code if they are bad, or you have an issue with your cat. If you have the cash go ahead and do these, otherwise just do the upstream ones. If one is throwing the code, I suspect the other is close behind it. As swartlkk mentioned the upstream ones are the important ones that can hurt your performance and fuel mileage.

Here is the link to the Bosch part on Amazon. http://www.amazon.com/Bosch-15703-Oxygen-Sensor-Fitment/dp/B000BZJ9Q0/ref=au_pf_pfg_s?ie=UTF8&Model=Blazer|420&n=1568418 1&s=automotive&Make=Chevrolet|47&Year=1996|1996&ne wCar=1&carId=001

I checked Bosch's website to confirm these are the correct part #.

Here is the Delco one: http://www.amazon.com/ACDelco-AFS105-Oxygen-Sensor/dp/B0013FWACW/ref=au_pf_ss_1?ie=UTF8&Model=Blazer|420&n=15684181 &s=automotive&Make=Chevrolet|47&Year=1996|1996&car Id=001

 

Bosch sensors were one of the worst ones I have ever tested. I do NOT recommend them. They are lazy out of the box when compared directly with AC Delco or NGK. And a sensors activity is a direct relationship with its life expectancy. Spend the extra money now!

 

Ok, I'll trust that. NGK looks to be the same price as Bosch. Delco is a little bit more.

The only reason I said Bosch was because of my experience with the sensor in my Honda. The factory installed one was a Bosch and I forgot to replace it at 100k. At 136k there was still no code. So I threw another Bosch in and it seemed to give the car new life almost. haha

Meanwhile the factory installed one on the Bravada (I assume Delco) threw a code at 98k.

Perhaps it's just apples to oranges because they are totally different cars? Maybe Bosch makes a good Honda replacement, but a crappy GM replacement?

 

The codes read bank 1 sensor 1 not enough effeciency, and bank 1 slow response. So its getting replaced. I have always like AC Delco spark plugs for my Chevys, so my choice will be them for the sensors. Now i just got to figure out my other codes and what they mean, but that will be on another thread.