WB O2 Circuit Comments

[Timothy J Burgess]

Greetings and congratulations on designing an extremely useful tuning aid -
I look forward to using it!  I have a few comments regarding the design:

Change R1 to R4 in the note on page 1.

What is the value of the calR pot?

Under what conditions should the heater Imax to be reduced from 1.5 A to
1.45 A?

It may be useful to provide a second output that is scaled such that 0.1
volts = 10.8:1 and 0.9 volts = 13.07:1 (essentially by subtracting about
1.3 volts from the existing output).  This output could be applied to an
analog mux that selects the stock O2 sensor output under part throttle and
selects the WB O2 sensor output at WOT.  The output of the mux would
connect the the ECM O2 sensor input.  This would allow easy WOT A:F ratio
data capture using the A to D in the ECM in conjunction with an AutoXray or
Diacom, etc., and would also allow the ECM to continue to operate normally
at part throttle.

I created a Digikey part number BOM from the parts list on the web site.
Unless it has already been created, I thought that it might be useful to
have it posted for peer review, corrections, etc.

I'm an EE and moderate the electronics board on thirdgen.org, so I look
forward to seeing you there, as well!

Tim Burgess

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