disconnecting 02's
 

I was reading on another forum where a guy's tuner had disconnected 02's on his blower car so that they could get the a/f adjusted right.

He claims drivability is good and his economy was right at 20mpg which is 'ok' in my opinion.

Why would there be a benefit from running without the 02's? Isn't this going to hurt the function of the MAF?

How would it hurt the maf functions? I thought the O2 were only for fuel economy. Years ago when I put the blower on thats what I was told to do by several speed shops. I know both the 89's will run fine without them, but both of preston's cars won't hardly idle without them.

You act like you've never done this before. Everythime you have turned adaptive off, you were essentially disconecting the O2 sensors.


Basically, you would just put the ECU into open-loop operation all the time. For this reason, you would have to have your tune dialed in perfectly. Also, any changes over time in your set-up would never be compensated for and end up causing your tune to be off over time; things like dirty sensors, increased oil consumption, etc.

It may work fine for a race car, but I think a street car would suffer in the long run.... not to mention fuel economy would never be near what it should be.

yes but these guys never hooked the 02's back up

So, nothing says that we have to turn adaptive back on after we tune. You can leave it off forever as long as you are confident that your tune is perfect and that your sensors will never deviate from their tolerances. However, in the world of street-driven cars, various sensors go bad or get dirty and motor tolerances change to the effect that tunes can begin to vary over time. These are the reasons we have closed-loop circuitry and adaptive technology.

To me, it just doesn't make much sense to bypass the O2 sensor feedback in a street car. There are just oo many variables that effect fuel use during normal cruising situations. It would be extremely hard to get your entire tune to be perfect for every situation.

No, all you have done is disable the adaptive learning procedures. You need to force full time open loop to get the ecu to ignore the O2 sensors.