Wideband as Narrowband

[3400-95-Modified]

I guess this isnt a specific OBDII question but what do you guys think on using your wideband as a narrowband O2 also? My PLX SM-AFR has a wideband output and a narrowband output, When installing my wideband I had to move my stock narrow band up to the crossover pipe as S&S placed the o2, this immediately took my decent part throttle tune and threw it out the window because I was reading all 6 cylinders with where I had it, now its only reading the front 3.

Would using the wideband as a narrowband improve my overall tuning capabilities? It seems to respond quicker than my stock narrowband does to begin with.

[bszopi]

Only thing I remember hearing about this is that its not recommended to keep the wideband installed at all times, as it will burn it out quicker. And since they are more expensive than a narrowband, replacing it will cost more. And you'll be replacing it more often than just a standard narrowband. Otherwise, using it for the narrowband output makes complete sense, as you what you are tuning by and what the PCM is adjusting for it coming from the same point in the exhaust flow.

[3400-95-Modified]

They cant die that often... But either way they arent all that expensive beleive it or not...

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[ForcedFirebird]

Seeing that the VW uses them in production cars makes me think that they will be fine with regular use.

I didn't like using the WB for the double duty and ended up using the NB for the ECM and the WB for the guage/laptop.

Your bigger issue sounds like the location of the sensor more than the sensor itself. Many people tune exclusively through the NB

[3400-95-Modified]

I would tune part throttle through the NB, but it shouldnt matter about "double duty" its really the box thats converting the signal to either a 0-5 or 0-1 and it doesnt work any harder doing both... I currently log the NB output too so I could see how close it was to the stock one.

as far as location I had the NB where my WB is now before, I just had to move it since I didnt feel like doing another bung right now... and that one was open.

[Superdave]

I use the narrow band sym on my wideband.. it seems to work ok although the voltage swings alot more than i'd like it to. That might just be beacuse it's monitoring the front bank instead of both though...

[3400-95-Modified]

your only monitoring one bank? You need two widebands

[sprucegagt]

No he doesn't. I've said it many times. If the engine has no faulty electrical/mechanical parts then the tune will be fine. What comes out of one bank will be exactly the same as the other bank. The only difference is the amount of exhaust gases going across the sensor, not the quality of the reading.

As for the original question, you should be able to use the narrowband sim just fine. The only problem may be when the PCM doesn't see the O2 heater circuit. You may want to leave the narrowband plugged in and tucked away from anything flammable (they can get hot). But get your signal from the narrowband sim.

[3400-95-Modified]

Your the OBDII moderator and you didnt think of the fact that you can shut off the O2 heater circuit code...

Also if the placement of the O2 didn't matter then why did my LTFT go from 1 to -1 up to +5 when crusing just by moving it from the downpipe to the front bank only.

As much as we dont want it to be different it is ever so slightly different... My injectors were cleaned and ballanced by witchhunter so I know thats not the issue, also all my plugs look good.

[PCGUY112887]

My wideband said they last about 60k miles, should be plenty considering the mileage already on most of our cars.

[sprucegagt]

Your the OBDII moderator and you didnt think of the fact that you can shut off the O2 heater circuit code...

Yeah I knew you could turn the DTC off, but that doesn't mean it won't cause a problem. When you tell the PCM to ignore the O2 heater circuit, it may very well never go into closed loop, since it can't regulate O2 heater temp. Did you ever think of that?

Also if the placement of the O2 didn't matter then why did my LTFT go from 1 to -1 up to +5 when crusing just by moving it from the downpipe to the front bank only.

As I said previously. What comes out of one bank will be exactly the same as the other bank. The only difference is the amount of exhaust gases going across the sensor, not the quality of the reading. Anyway, what proof do you have that your NB O2 sensor didn't loose accuracy due to being moved? It is a very delicate sensor and just the act of moving it can be the reason for your tune change from 0 to 5 LTFT.

As much as we dont want it to be different it is ever so slightly different... My injectors were cleaned and ballanced by witchhunter so I know thats not the issue, also all my plugs look good.

Well then think about it. If the injectors are clean and balanced, the plugs are good, I'm willing to bet your compression is good, the 3X00 engines don't run a dual plane manifold, nor a carb, why would one bank be considerably off tune from the other? Give me a good answer to this and I'll give your theory some credit.

One would think that Dave's times alone would be reason enough to believe that tuning from just one bank is really not all that bad.

[3400-95-Modified]

I'm not saying it would be considerably better or worse bank to bank, but they are not 100% equal. As soon as you put oil in the car, and run one tank of gas through those newly balanced injectors you've infected the system with multiple contaminates, maybe little ones, but sometimes just enough to vary the flow of one injector to another.

I feel that if your monitoring the front bank only you wouldn't catch say a rear injector failing out as quick... Maybe I'm wrong but I think that would show up on the overall reading.

Remember this isn't a perfect world... nothing is created equal even if you want or think it should be.

Ok bottom line I can change the DTC Reporting section to not report that code, I can almost guarantee that wont mess anything up. And I can use my wideband as a NB sim without any issues and others have done it... Ok, question has been answered.

[sprucegagt]

I agree with the contaminates deal, but the effect would be uniform, not bank to bank.

If an injector started to go out, I can see it affecting the O2 signal in a negative way. It would make the O2 run lean making the PCM richen things up too much and cause a rough idle/performance. Now if the O2 was in the good bank instead of the bad bank you wouldn't have this problem. Instead you would get constant KR that would not go away. If you have an injector go bad regardless of bank, it will still turn on the SES since the MAP sensor is used to pick up a misfire(it sees the momentary hiccup in vaccum signal and the PCM correlates that with the firing order), not the O2 sensor.

[asylummotorsports]

This is all quite interesting.

The info I rec'd from PLX when ordering my wideband was to install it further "downstream" to allow it to see somewhat cooler temps. (Who knows how much though)

I still have the narrow band in the header (S&S) monitoring the front bank only, and the wide band welded into the cut-out which is about under the drivers seat.

It is interesting to watch the read-out AFTER a hard run at the track as it leans way out, and then slowly works its way back to normal.

Now I'm not sure if that is what is suppose to happen, but I will be asking.

[sprucegagt]

That's a problem with the NB sensor. When it gets hot during a hard run it will read lean. You can see this if you hot lap at the strip. It's one of a few reasons why you really shouldn't trust it for WOT performance.