02 bung welded, ready to resume MPS tuning Options

[rfinegan]

I had a little free time to day so I decided to add(weld) the O2 bung to my Bursch exhaust

wide band O2 is now ready to go....

[pbanders]

Forgive my ignorance, but exactly what kind of tuning are you doing? If you're using a stock 1.7 or 2.0L motor, and the correct D-Jetronic components, and they're all in working condition, the MPS does not require any tuning.

What motor do you have, and is it modified? The MPS can be adjusted to set the mixture/CO/AFR for part-load, and also for full-load and the onset of transition to full-load operation. Idle condition mixture is set with the knob on the ECU. Engine speed correction (pumping efficiency) adjustment is more complex, and requires modification to the multiple waveform shaping circuits on the ECU daughter board.

With regard to using even a wide-band sensor with your exhaust bung, you will likely only be able to tune accurately for part-load and full-load operation. Idle condition tuning requires a CO meter that reads in the range from 0 to 5% (or an AFM range of 12.5 to 14.5). Maybe wide-band sensors are better now, but I believe they have accuracy problems in that range, because the O2 curve in that range is very flat and low signal. You might be better served by going to a tuning shop and using their dyno and pro 5-gas analyzer.