Bosch O2 sensor

[PCGUY112887]

After seeing some comments from members on Bosch O2 sensors... do Bosch O2's really suck that bad? I have one in my 3500, it seems to work but when I scan my O2 values are EVERYWHERE. It makes no sense really, the values it shows would have to make the engine run like crap (or not even run!) but it runs fine. On the Powrtuner forums they suggested that I may have an exhaust leak causing crazy numbers like I have, but I sure don't hear a leak and don't think I have a leak. I have wondered if it was due to the fact that my headers are setup so the O2 only reads from 1 bank (the front) but I don't know how it could be.

Engine runs fine, wideband shows that the engine runs fairly normally, but the numbers are nuts. Maybe my sensor just sucks in this case?

[3100 MPFI]

I just put one on my twin cam, but it was only because I didn't have any other options. That was all that they had in stock, and they said it would take 3 days to get a different one. I needed it right then, so I went with it. It does have a 1 year warranty. I think I will keep this one, and in about 6 months, have it replaced for free, and then keep that up for as long as I am broke.

Once I get some money I will get either a DELCO, or a STANDARD. Those seem to hold up the best.

FYI, when I first got my 1990 STE, and inspected it for the first time, it failed because it needed an O2. I got a bosch one, and it passed, but 3 months later the car started running rich, and I traced it back to a bad O2. I put in a new one, and same thing happened 4 months later. I got a STANDARD one after that, and so far it is going on a full year, and no problems.

[1988GTU]

What numbers are you reading? ... and Bosch o2's suck.

[PCGUY112887]

My numbers are just all over the place... will go from the regular 800-900 readings, to things like 17, 125, 64, 500, anything, and it constantly does it. My logs from Powrtuner look crazy, if the numbers were real I don't think the engine would be running.

I have a CVS file of the scan if you wanna take a look at the values...

https://www.theopia.com/scan-tune.zip

[IsaacHayes]

I'm happy with my Denso.

[ikessky]

I put a brand new Bosch in and had codes pop up with in 15 minutes of starting the car. I replaced it with an AC Delco and everything worked fine.

[geldartb]

at idle your O2 numbers will bounce all over the place thats normal.

i got the one that came with the 300 mile motor stock all i did was switch the end plug cause the 05 3400 has an extra tab that makes it not fit with my car.

[Canyonero]

I just changed my pair of HO2S over to AC Delco. They look IDENTICAL to the Bosch, down to part numbers and little logo printed on it (serial # is different of course). I noticed that the sensor in the left bank (RWD block) was black with carbon buildup on it while the right had little. I filled the tank and took the truck fishing this last weekend right after I changed the sensors, and after about 200 miles the gas mileage is looking pretty reasonable (for a Trooper with an iron head, >15MPG). It's at least what I got with my 2.8 TBI, but now I have more power.

The second half of the tank will be mixed semi-rural town driving, so we'll see how it ends up. I might be on the AC Delco wagon too. I'm going to snap a picture of those Bosch sensors and see if anyone can identify the common logo printed on them.

[sprucegagt]

After seeing some comments from members on Bosch O2 sensors... do Bosch O2's really suck that bad? I have one in my 3500, it seems to work but when I scan my O2 values are EVERYWHERE. It makes no sense really, the values it shows would have to make the engine run like crap (or not even run!) but it runs fine. On the Powrtuner forums they suggested that I may have an exhaust leak causing crazy numbers like I have, but I sure don't hear a leak and don't think I have a leak. I have wondered if it was due to the fact that my headers are setup so the O2 only reads from 1 bank (the front) but I don't know how it could be.

Engine runs fine, wideband shows that the engine runs fairly normally, but the numbers are nuts. Maybe my sensor just sucks in this case?

Your O2 numbers are fine. During normal idle/cruise operation it will bounce between almost 1 volt and almost 0 volts. In fact, it bounces so fast that Powrtuner can't record it fast enough. If it did you could graph your values and they would look like a sine wave. I also wouldn't worry about the whole O2 in one bank deal. As long as the engine is in good operating condition, it won't cause a problem.

[Canyonero]

However, it does cause a problem when you have an O2 sensor for each bank and you plug them in backwards. Well, that's what I've heard anyway...

[lkurek]

You have enough wire in the harness to wire them up in the wrong bank? I'd be shocked if that is even possible.....

But yeah, if you have two sensors (one on each bank pre-cat) then the PCM will try to set BLM and short term fuel trim on each bank differently. If it thinks it is reading the right bank, but it is really the left.....yeah, that would be interesting

[Canyonero]

It's a custom 'standalone' harness. I think they mixed the wires up when they assembled it, but luckily there is still enough to cross over eachother and connect properly.

The performance suffers when you go into closed loop of course, starts running pig rich and backfires.

[PCGUY112887]

I am going to scan my friends car (stock) later to see if I get similar readings (numbers all over the place). Thanks guys, I will update this soon.