K&N Rich-lean monitor

[George M. Dailey]

O2 monitoring systems offer a narrow range of rich/lean indication. They are
analog systems, but the o2 sensors itself is only accurate in a very narrow
range. In Mississippi talk, it will tell you that you're running rich or
lean but the actual a/f ratio that is displayed will not be very accurate.
Check the DIY_EFI archives. There are many megabytes on babble on this subject.

The Rochester electronic feedback carb (any feedback carb) are considered
abominations! Think about it, all the headachs of a conventional carburator
plus several other expensive sensors, actuators, an ECM, and miles of wire
and connectors thrown in to ensure complete insainity.

Before you lay down your money, let me recommend the following. Purchase and
install a new o2 sensor ($30). You should have a mounting boss on your
exhaust already. Chunk the old o2 sensor. It was probably rated for 15,000 -
30,000 miles. Connect a DVM and measure the voltage off of the o2 sensor
directly.

If you really want to get funkey, build a circuit to send a pulse width
modulated signal to the mixture control solenoid on the feedback carb. You
will then be able to vary the a/f ratio on the fly and see the a/f ratio
changes with your DVM. The factory ECM does this better than any person
could, and it's faster. Don't use the ECM if you don't want a compromise
between power and economy.

You're best bet is to scrap all of the feedback carb system and put a GM TBI
system on it. It will be better, cheaper and easier than bringing an old
feedback carb system back to life. Check the archives, there was lot's of
babble on this also.

GMD


At 07:47 AM 2/15/97 -0600, you wrote:
>This is a non fuel injected question, however I thought that the 
>expertise of the group may be able to answer it. I have a 1987 El 
>Camino with the Rochester electronic feedback carb. The prior owner has 
>disconnected the computer and some of the emissions hardware and I am 
>trying to get it all back together.  What I would really like to do is 
>switch over to fuel injection, however I don't have either the dollars 
>or expertise at this point. 
>
>I saw in a book that K&N sold a rich lean monitor that is used as a 
>tuning aid.  It utilizes a probe that is welded into the exhaust 
>system. Has anyone used this and would it help me in my application?
>
>George
>
>Clark, N.J. 
>
>