O2 Sensor output voltage

[08calspecial]

Hi guys, can someone tell me what the o2 sensor output voltages are supposed to be? I can't for the life of me get my catalyst, oxygen sensor and oxygen sensor heater monitors to ready.

I have a tune but my sensors should be on.

Looking at the data stream on my obd2 reader my O2S11 and O2S21 fluctuate from .05V to .8V and the O2S12 and O2S22 sit right around .06V at idle. Is there any way from this to maybe tell what's going on?

 

[redfirepearlgt]

.1-.9vdc is the range of an HO2S narrow band sensor. Lambda 1.0 (stoich 14:1) = .45 -.50 vdc.HO2S sensors at startup will be inactive for a few seconds until the heaters bring them to operating temp. Mine start showing activity about 10-20 seconds after a cold startup as I recall. I hope the .05vdc on the front sensors is not the actual value at idle after they have become active.

As for rear sensors, are you running cats or not? Either way I believe many tuners will disable them unless you request them to be left on. Best bet is to call the tuner and have them verify this. I can only speculate where as they can present fact.

 

[08calspecial]

I have long tube headers and high flow cats. I know I'm kinda playing with fire but I didn't have to get it emissions tested until I moved so I wasn't worried about it then.

The tune I currently have is from Lund Racing and they claim the sensors are on.

So are the sensors that end in 2 the front ones? And should they oscillate too? The scanner on the obd2 port definitely shows the other ones oscillate the whole way down to .05V and not stay above .1V is that a problem too? I just replaced the rear sensors just in case that could be it. I figured if the fronts were bad I'd be getting a CEL, which I'm not.

 

[08calspecial]

So I tried to look it up but man do people over complicate it. From what I can tell 11 is Passenger front, 12 is passenger rear, 21 is driver front and 22 is driver rear.

The fronts continue to oscillate pretty much the whole time. At idle the rears are down around .05V but when driving they jump around some. They definitely aren't oscillating like the fronts are.

I'm getting horribly frustrated with the whole thing.

 

[redfirepearlgt]

I have long tube headers and high flow cats. I know I'm kinda playing with fire but I didn't have to get it emissions tested until I moved so I wasn't worried about it then.

The tune I currently have is from Lund Racing and they claim the sensors are on.

So are the sensors that end in 2 the front ones? And should they oscillate too? The scanner on the obd2 port definitely shows the other ones oscillate the whole way down to .05V and not stay above .1V is that a problem too? I just replaced the rear sensors just in case that could be it. I figured if the fronts were bad I'd be getting a CEL, which I'm not.

Sensor 1 bank 1 and 2 are the front sensors. Sensor 2 bank 1 and 2 are the sensors after the cats that are checking only for catalytic functionality. How those will react with high flow cats I could not answer. Thankfully I have no smog testing crap to deal with. The day I do I either move or re-license the car in my parent's state and keep it there or get out of the hobby all together and take up golf again. Hopefully someone in your boat can provide you with more 411 on how to resolve that. I know it has been discussed on here quite a bit.

There will be some variation at idle or any held RPM range, therefore your voltage will vary slightly if the O2 sensors are active and working correctly. The better the tune, the tighter that will be, but there will always be some variation.

Are you using Livelink with your SCT to collect data or some aftermarket hand held device or what? If you have a Lund tune I assume you have an SCT tuner. Obtain a laptop and download their livelink and do some datalogging with that. It's a very handy tool to have.

 

[08calspecial]

I just have an obd2 reader that shows the data stream. Obviously not great. I'll look into livelink and try to record some data.

 

[redfirepearlgt]

Here. Found this int he online diagnostics handbook. It explains the monitoring function of the cat between the for and aft sensors and some other good information. With your OBD2 you should be able to use this 411 to determine how the high flow cats are rating and so forth. Hope it helps. Its out of the Ford tech manuals for the 05 4.6L 3V.

http://iihs.net/fsm/?d=7&f=Catalyst Efficiency Monitor.pdf

 

[Joe88xj]

Hey OP I am having the same problem with the same setup I have mid length headers and pypes hi flow cats and am at 300 miles and my catalyst monitor and my 02 sensors are "inc" I am using Bama tuning they sent me an emissions\inspection tune to run till I can pass PA inspection. Did you figure your problem out??