So in the mix of trying to figure out why my truck might be slacking off to say, I decided to monitor the MV readings using my scan gauges... There are 3 readings for the O2s in which according to Aeroforce are:

1 OXYGEN SENSOR B1-O2 bank 1 sensor 1 in millivolts

2 OXYGEN SENSOR B2-O2 bank 2 sensor 1 in millivolts

3 OXYGEN SENSOR – alternate O2 sensor parameter, rarely supported.


The first reading will go anywhere from about 50-800mv.

The second reading will only stay between 400-500mv.

The third reading will go anywhere from about 50-800mv.

So if anyone out there can help shed some light id appreciate it. To me this obviously states that I have an O2 that is not functioning properly, but at the same time I have no idea what the third reading would be. Im assuming its reading a POST-cat sensor.


Thanks for the help!

 

Your likely spot on with all of your assumptions to be honest. If the second reading truely is for one of your front o2's then that one is likely bad or you have a wiring issue of some sort.

 

Yea Ive pretty much decided Im gonna replace both front O2s but since we still have 6" of snow on the ground, im gonna have to suffer through the bad gas milage for now. Gonna check my STFTs later on today to confirm that one is reading off.

 

Im having the same problem. My bank one is staying 500-600 no matter what. Its dead. Runs like **** because of it. Rock auto has them for 32.00 a piece for the the front by Denso.

 

Ive had the same issue for some time. One o2 flops way down to 80, up to 600. The other stays solid 500-600 range. I swapped my o2's from side to side, same thing happened tho. Both ways, the o2 flopped on the drivers side.

 

Usually when they get old(sluggish) the DTC you get is for insufficient switching meaning the frequency is to low. A new sensor will switch quicker, but it won't change the amplitude of the signal if you're stuck rich or lean. If you get a sensor that goes from 400mV to 500mV that's near perfect fuel control since stoich is 450mV. You don't see that kind of precision control most of the time. The swing is usually much wider from say 100 to 800 and back as long as it passes above and below 450mV. The post cat O2s are supposed to mirror the pre cats, but with a reduced amplitude if the cats are working properly.

 

The sensor that is flopping is the one that is functioning properly, an O2 sensor should switch from rich to lean rapidly (something like 8 times in 10 seconds, can't remember exactly). I'd be looking for a rich condition on the right side, or a wiring/connector problem there.

$32 for Denso sensors? That sounds like an awesome price as far as I can tell...Denso makes excellent electronics and their stuff is usually expensive. I'm tempted to go buy 2 now just to have for when I start to have problems with mine (actually I was having problems with my r/s sensor right before my trans took a dump, now that I think about it)

 

whats the part number on those 32 dollar denso's?