SO I won't tell the story behind my car, just that the only mods are intake, exhaust, and PFC basicly. It was tuned by a prominent tuner up to 12 PSI. The engine however seems to just be dumping gas under all conditions. I haven't got my AFR gauge yet but I am trying. Now I hooked the Datalogit up to the car yesterday and pulled the maps. It seems to be programmed a decent amount richer, and the O2 feedback control was Off. I plan on using this as more of a cruising RX than a speeding one, so I would like to get the cruising tuning down way better than it is... Wouldn't 02 feedback be helpful for this?

Also. What exactly does this setting represent? The manual tells me the default value but thats it. 1.04 What? Volts? PPM? Is this a target setting for the sensor? A multiplier of some kind? Damn ambigious instrunctions.

Anybody got a link to a thread which explains these things?

Any help is greatly appreciated.

 

Stock/Narrowband O2 feedback won't help you there.

Most tuners tune for power and run richer A/F ratios.

So you bought a hardcore sports car so that you could use it as a Grand Tourer / cruiser car? Gotcha J/K

 

The O2 FB monitors the output voltage from the stock O2 sensor, and then uses the values within the INJ and BASE maps (idle and low cruise area), and the Settings 1 O2 Feedback value to adjust the fuel to try and obtain a certain AFR.

If a RECALC was run on the INJ maps so that the values are all 1.000, the O2 FB will not work and will cause a worse idle. Thus it has to be turned off.

You can actually tune a car to run leaner for idle and cruise for better mileage and cleaner exhaust by turning off the O2 FB, RECALCing, and adjusting the INJ map, etc.

My car runs so clean at idle and cruise that the exhaust is no longer black or very dark gray. It is medium gray, the plugs and O2 sensor come out cleaner than they ever were even when 100% stock.

My tuning notes cover all of this.

 

It would seem to me that tuning for the highest power numbers would be easier than drivability tuning. I can always have a map for power and a map for cruising. I am determined to learn how to do this. I am a professional technician so it should be within my reach. This is why I am very happy with a slightly modified car as a testbed for technology. Better to make mistakes on a car which hasn't had a ridiculous amount of money spent on it, no?

So, now that I addressed your response (first guy), which did not answer the question, I ask again:

What does the adjustment for O2 feedback control represent?

The number in my PFC was 0.699, which is mute because feedback control was off.

This is going to be a street car which can have a cat installed and pass emissions once a year. And I noticed that in the sample map and most base maps it was enabled, and since I am only barely modified from stock...

That makes sense CEW, my PFC was RECALCed, so I may not use the feature. But I still want to know: what does the number in Datalogit represent??

 

The engine does not need rich AFRs for idle and cruise, only for high boost like
10 to 16psi.

 

The docementation I have on this is not real clear (such is what we know about the PFC) but here is part of it.

The P-FC has a normal setting of 1.047 for the O2 feedback control; that is the coefficient where it goes into open loop. The P-FC looks into the current cell of the fuel correction map (INJ MAP) and then compares the value with the value from the o2 feedback setting, if it's above, the P-FC goes into open loop, below that value the P-FC is in closed loop.

Wih O2FB off, the value is not used.

 

Did you notice the J/K and smiley at the end of my comment? You wized off on my thread and find issue when I did the same on yours??

Glad Chuck provided the appropriate info. I had understood otherwise.

 

The value entered is a percentage. 1.04 would mean that the ecu will adjust the calculated injection amount up to 4% to reach the AFR value specified in the Fuel Map (not base fuel, but Fuel Adjust).

Don't you love it when people answer the question you ask?

 

O2 feedback is not meant to save fuel, it's meant to extend the life of the cat. If you want good fuel economy, tune it as lean as you can while maintaining good driveability. Buy Chuck's tuning notes and you will have everything you need to know for doing this and a lot more.