wideband VS. narrowband O2 readings

[99gst_racer]

Quick question: I'm logging both, wideband and narrowband on my loogger. At the top of third, I am showing a narrowband reading of 1.0, which seems rich to me. And I'm showing an AFR of 11.88:1, which seems a little lean to me. Is this common? Should I just ignore my narrowband readings and tune with the wideband only? Any advice would be appreciated. Thanks.

 

[RavenX]

Am surprised your using the narrowband simulation as ive heard they are crap. Don't bother comparing that to your wideband afr. As long as you don't have any exhaust leaks then just pay attention to your wideband only. I have a plx wideband and i used the narrowband simulation and even though it worked it wouldn't go past .80 volts and at idle it would stay alot at .00 volts so i ended up getting a new front 02 sensor and called it quits. Ive heard it either works for you or it doesn't. By the way am surprised your running 11.8:1 i hope thats not on pump because if it is i hate you

 

[99gst_racer]

Am surprised your using the narrowband simulation as ive heard they are crap.

Yeah, narrowband is not the most accurate readings in the world, but they are close from what I understand. I've never relied on them to the point where I tuned by them, but I still pay some attention to them. It's just kinda weird how my narrowband is showing I'm getting richer, and my wideband is showing I'm getting leaner..... I wouldn't expect them to show the same readings, but I would expect them to have a simular 'curve'.

As long as you don't have any exhaust leaks then just pay attention to your wideband only.

Yeah, no pre-sensor exhaust leaks here. I got all of those fixed right before the WB install.

By the way am surprised your running 11.8:1 i hope thats not on pump because if it is i hate you

Yeah, that's on pump gas (22 psi on my 50-trim). What's your AFR on pump?

 

[RavenX]

I was running 11.0:1 on pump gas but a few days ago i ran 100 octane and bumped it up to 11.5:1. The 100 octane has been since gone and theres only 93 in there and i haven't changed the settings. So am surprised that its running 11.5 when the car knocks at anything over 11.0. No knock yet so we'll what happens

 

[project_tsi]

I was running 11.0:1 on pump gas but a few days ago i ran 100 octane and bumped it up to 11.5:1. The 100 octane has been since gone and theres only 93 in there and i haven't changed the settings. So am surprised that its running 11.5 when the car knocks at anything over 11.0. No knock yet so we'll what happens

If your knocking at that AF ratio, try taking some timing out, adding some fuel, or run a bit lower boost. You shouldn't be knocking on pump at a 11:5 ratio. Shit I run 25psi on 93 w/ a 12.5 AF. No knock, but I do have Link.

 

[Staytuned]

Something doesn't seem right there Paul. I will do a log with mine tonight and post the results.

 

[99gst_racer]

Something doesn't seem right there Paul. I will do a log with mine tonight and post the results.

Thank you Steve. Also, if you could, please log your narrowband along with your wideband. I would like to see how your readings compare to mine.

 

[Staytuned]

Will do Paul.

 

[Staytuned]

Paul I see .9v narrow band O2 readings for AF ratio's from 12:1 to 11.5:1 and I see .92v for anything from 11.3:1 to 10.9:1.

 

[99gst_racer]

Paul I see .9v narrow band O2 readings for AF ratio's from 12:1 to 11.5:1 and I see .92v for anything from 11.3:1 to 10.9:1.

Yeah, your's reads correctly; that's about what they should be.

My wideband is reading .94 which I calculated to be an 11.88:1. And my narrow band is reading 1.00.... And recently, I am getting bucking at high RPM followed by a puff of unburned fuel out the tailpipe. I have a very good feeling that my narrowband is reading correctly. My LTFT is also agreeing with my narrowband. I am going to play with the AFC and see if I can fix that.

Also, I have my wideband wired through the 0-1v output. I'm going to try the 0-5v output and see if I have any better results.

 

[diambo4life]

Also, I have my wideband wired through the 0-1v output.

Why? Why is it called wideband again?

 

[99gst_racer]

3 bars of green, you should know this by now... but for future reference again.

3 bars does not make me a know-it-all. It just means I answer other's questions well. I am not a tuning expert, but I am definitely car smart. As far as your graphs; I know and understand them very well. And I've posted the (V*2) + 10 equation in threads in the past, so I obviously know and understand that as well. I know to tune by WB and not NB. My main question has nothing to do with which one to use and why.

I am curious as to why my WB progressively gets leaner as the RPM rises (as it should) but it is reading almost too lean for pump. And my narrowband shows I am progressively getting richer as the RPM's rise.

My spark plugs are also showing a rich mixture as well as my LTFT. I get unburnt fuel out of my tailpipe and I can't go WOT without bucking. My gas mileage is horrible.

That just leaves me wondering why my narrowband seems to be reading accurately and my wideband is not.....

And my previous question: Why is one going leaner and one going richer? Regardless of accuracy, you would think they would at least be headed the same direction..... right?

 

[hellotbone]

If I tuned my car on pump at 20 psi to 14.7 on my WB I would be picking up the pieces laying on the road.

 

[99gst_racer]

Using your .94 as a negative value, I can calculate a 8.12 AFR and I wanted to let you guys know I didn't just pull this completely out of my ass.

+0.5v is 11
+0.0v is 10
-0.5v is 9
-1.0v is 8

I did a lot of thinking about it, it is damn linear, maybe the logger cannot determine if the voltage is pos+ or neg-, which would make sense that all of a sudden his reader is showing the voltage go up, which would be leaner, but infact if it was neg- it would be getting even richer.

See, now that makes much more sense now. So you think if my car is rich enough to dip lower than a 10:1, then the voltage that the logger shows is really negative???? That's interesting..... I will be out at the garage either today or tomorrow, so i'll give it a try and see what I come up with..... Thanks for your help Curtis.