How do I tell what my Air fuel ratio is in Free Scan?

Thanks

 

Its on the Engine Data tab, but I've never seen it work.

 

I can not get it to work either. I heard that Datamaster's A/F thing works- I'll have to check it out

 

The problem is that as far as I know it still takes the info from the stock O2 sensors.
The A/F ratio would not be reliable enough to tune on but if you were just curious about a rough A/F ratio it would work.

 

Thanks,

So the only thing that would work is something like the FAST system that has its own wide band?

 

That or maybe just take it to a Dyno shop that uses a Wideband.
I would be more inclined to find a Dyno.
You can do a hell of a lot of pulls for the price of a FAST system.

 

In Open loop it does not use the O2 sensors (correct me if I'm wrong), it uses calculation in tables instead.

But I would't buy a whole new stand alone PCM. I think you can buy good A/F gauges and tune off of that.

 

Originally posted by dayusmc
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In Open loop it does not use the O2 sensors (correct me if I'm wrong), it uses calculation in tables instead.

But I would't buy a whole new stand alone PCM. I think you can buy good A/F gauges and tune off of that.
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You are right about Open loop. The O2 are not used, however I personally wouldn't want to make a very drastic change by relying on the O2 or the table.
When tunning for power you are always better off tuning from a dyno with a wideband. The conditions are repeatable and therefore more accurate.
A lot of people just set the A/F vs coolant temp table to 65* and then adjust the A/F vs RPM. This takes one variable out of the mix. Dr. Drudge has done this and could probably explain it better than I can.

You can tune A/F any way you would like but I would always stay on the side of caution, being a little rich never hurt anyone.