O2 or no O2

[S13FX]

Quick question.

Since I'm already adjusting the AFR's with a safc and using a wideband to tune, do I still need a O2 sensor? or can I just plug up the bung after Im done using the wideband?

[Bigvinnie]

Quick question.

Since I'm already adjusting the AFR's with a safc and using a wideband to tune, do I still need a O2 sensor? or can I just plug up the bung after Im done using the wideband?

OMGWTF I bet you haven't even read the SAFC manual yet.......If you did you wouldn't say something as retarded as you did.....

[Ligouri Rd]

To answer the question: You need to leave the stock primary o2 sensor in place. That is how the engine controls the fuel mixture during cruising conditions. You can possibly use the wideband's analog output to feed the ecu the o2 sensor's signal. It would be easiest just to weld another bung on the manifold and plug when not in use.

[S13FX]

Yah I read the Manual like Bigvinnie suggested, and came to a conclusion why you need the O2, but also after I read it I realized how stupid I was for asking this question when the answer is so self explanatory, anyways my wideband O2 has a narrow band out pout for the ECU :-p

But also Bigvinnie, I know your tired of people probably asking stupid questions, but you have to realize that not every can be blessed with info like you are, and there will always be questions of this type. So next time you should take it easy, and even though that was a good suggestion, you could have been a lot nicer giving that answer. Thanks anyways.

[Jiggyfry]

Well put, im noticing people would rather attack than give less informed people a good foundation for learning. Everyone started at the bottom, dont forget that. by the way, what kind of wideband are you running, and hows the quality since im in the market for one. I have the safc2 but no wideband! Where's my wideband?

[Bigvinnie]

Widebands are a monitor device for fine tuning. Usually in order to get PERFECTLY fine tuning the stock O2 sensor should be left inplace at all times (for widebands without a narrow band port), especially for eccs and using piggy back systems. Removing the O2 while tuning the SAFC is a stupid thing to do. You should leave the stock O2 in place and then a bung should be put into place some where before the cat for installation o fteh wide band (again if it doesn't use a narrow band port).Not all wide bands come with a narrow band port, and you should make that clear as well. Wide band sensors arent meant to be left in for long priods of time either so yeah after you are done tuning you should put it away. Appoligize for my impatience.
Modified by Bigvinnie at 12:46 PM 5/13/2006

[S13FX]

Oh no you know what I think you tottaly miss understood my question too hehe, sorry about that heh. I know all that information about the widebandm, and the narrow out put, and that widebands get wornout at a faster rate. This was my real question however, let me see if I can make it clear heh.

My question was, since the SAFC interupts the MAF signal which helps the ECU set correct AFR's by adding or subtracting fuel, and that's controlable through the SAFC, why would I still need the O2, sensor.

Because isnt the O2 sensor that gives the ECU the AFR's and then the ECU sets the Air and Fuel according to those readings. But since Im using the SAFC to interupt the MAF signal and set the AFR's anyways why should it matter.

Now I have read up on this matter a lot more in the last couple day's , and I tottaly spaced out on the whole open loop and cloesd loop system.

So now I more or less know what the deal is.

Just though Id chime in and sorry about that I also didn't make my self 100% clear so that could of been the problem. Thanks guys..

[Bigvinnie]

Because isnt the O2 sensor that gives the ECU the AFR's and then the ECU sets the Air and Fuel according to those readings. But since Im using the SAFC to interupt the MAF signal and set the AFR's anyways why should it matter.

You pretty much just answered your own question. In open loop, the ecu runs the engine rich, until the engine is warm and stable to run a stoich mixture, or some what close to lean mixture.No matter what, don't confuse yourself between tuning the SAFC to the MAF, all it does is change and fool the ecu's direct signal from MAF to ecu which somewhat changes the timing of the engine, and somewhat the amount of fuel, teh O2 actually determines consistency. No matter what in order for that configuration to stay consistent in closed loop your narrow band O2 must be used at all times. The O2 is the importance in operating how much fuel would be dumped and how limited it is from the voltage signal that was sent over to the MAF. It reads the mixture after burn off to match consistency. That is what determines the amount of fuel, the APEXI guide just simplifies things without directly telling you what each particullar device to the engine does.Plain and simply removing the O2 sensor, offsets all the fuel calculations that you had just tried to fine tune with the wideband. Removing the sensor automatically drops the ecu into safe mode and retards timing, and increases fuel. OBD systems do this in order to prevent detonation from happening which is dangerous to the engine without it.

[S13FX]

Wow man, that's what I thought the whole time but it took me so much diggin on line and puting 2+2 together to get that info and here you go summurized it in a nutshell thats awesome.