On Sun, Jun 17, 2012 at 4:32 PM, John Meeks <vanagon@gmail.com> wrote:

> Is the best way to verify this adjustment to find someone with a NOx
> sniffer?
>

Nah, you can just use a wideband oxygen sensor. NOx is a secondary effect
of lean mixture, so you might as well measure mixture directly so you can
tell if it's rich also. I got a cheap AFM off eBay years ago that had been
horribly maladjusted and got it to work with my wideband O2 meter. I have
the older version of the Innovate Motorsports LM-2:

http://www.innovatemotorsports.com/products/lm2.php

That, plus an O2 sensor socket to remove the stock  lambda sensor and plug
in the LM-2 wideband sensor, and finding the issue with an AFM isn't too
hard.  NOTE: you must run the engine warmed up, in open loop, and aim to
bias a little towards rich rather than the stoichiometric 14.7:1 ratio.
This was YEARS ago, but as I recall, the Bosch book says Digifant ECU
defaults to the WOT table on open loop, which ought to read somewhere in
the neighborhood of 13.5-14 air to fuel ratio.