At 08:26 PM 3/15/01 -0600, you wrote: <SNIP>
> However, can someone explain to me how these A/F guages are
>useful and/or accurate if our 02 Sensors are constantly fluctuating from
>0-1V (thus the guage will also be fluctating all the time)? <SNIP>
The primary flaw in their usefulness is that they cannot be more accurate
than the information coming from the O2 sensor. However, they are small
enough to mount permanently, readable enough to glance at when driving,
and cheap enough to be a worthy addition if you start messing
with your truck. They respond very quickly, alerting you if your latest
"improvement" causes lean running, or if something in the fuel supply
system malfunctions.
What these inexpensive A/F meters won't do is to give you a high resolution,
accurate reading of a performance oriented A/F ratio. The range of most of
these meters is about 16:1 on the lean side, to about 12:1 on the rich side,
with most of the LEDs and needle types unmarked. Two factors become obvious
here:
First, if you are looking for an A/F ratio near 12.5:1 an A/F meter of this
type
will be close to the end of its range (where the information coming from the
O2 sensor is least sensitive). Second, if the "rich" side of your A/F meter
only contains five or ten LEDs above stoichiometric, you won't have enough
resolution to see very small changes. While these limitations seem to damn
inexpensive A/F meters to near uselessness, that is not the case. The
information they give you, when combined with other observations and
experience with the vehicle, can be very valuable--especially if you have/added
some manual control of your fuel delivery system. The resolution on the meter
is consistent with the quality of information coming to it from the O2
sensor. So,
even though the absolute readings may not be reliable, seeing if the
reading stays
constant as revs build up is very valuable.
O2 sensors do not often fail outright. On a properly maintained vehicle, they
will gradually slow down in their output response (much the same way that
shocks do). At the idle, the indicator will crossover the stoich marker about
once per second ... at cruise or under acceleration, about 2-3 times per sec.
If this crossover slows down, the reason may be an aging O2 sensor. If the
gauge shows a constant lean/rich condition at idle or cruise, than it's a sign
that some thing major is wrong and it would be wise not to drive it any further
until the exact cause is found.
>Also, who is using Autometer A/F guages? Could you look at their online
>catalog and tell me the part number you are using? Also, for those using
>Intellitronix A/F guages, which one are you using?
>www.autometer.com http://www.intellitronix.com/airfuel.html
>Thanks again! Kyle 93 Dakota 4x4 V6
I'm using the K702 Intellitronix located in a 2-pod gauge holder attached
to the A-pillar. Because you already have the O2 sensor on the truck,
you do not need to get a 'sender' unit.
A week or so ago, I posted for you a description on how I installed this unit
on my truck.
Bob
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