I bought the Car Chip which is a small microcomputer

with flash memory that you plug into your OBD II connector
under the dash.

http://www.davisnet.com/drive/products/carchip_products.asp

Here is some of the results of the five parameters
that can be chosen out of three dozen or so to be recorded
for up to 300 hours. I was interested in the fuel mixture
as a function of engine temperature. My theory is the
manufactures are richening the mixture when you start your
car to light off the catalytic converter resulting in excess fuel
consumption during start up. I am still collecting
data as in this case the engine did not start from cold
but was at 150 F.

I suspect this so called "trim" is a percentage above
and below 14.7:1 stoichiometric. For example + 12.5% above
would be 12.86:1 rich.... I think.

Notice the 2004 Honda Odyssey engine spends most of the time on
the lean side even at 65 MPH.

Paul Lamar ...No rotor no motor.

Wow! neat data, just what I need for the cheap EFI programming.
Thanks Paul.

Doc Custer
Retired Software Engineer and sometime Audiologist

More to come shortly.

OK Doc,

Here is the results of a short trip to the gas station.
Note the engine started at 60 F at stoichiometric. It then
went lean almost immediately. As I recall the RX8 engine
was stoichiometric 99 % of the time. Perhaps Honda is on
to something here. I won't know for sure until I use
the same data acq CarChip on the 2004 RX8.

BTW the percentage load is misleading. That is a percentage
of peek power at that modest RPM. For example 50% of 50 HP
at 2000 RPM is 25 HP. At least I think that is what it is
saying.