[Diy_efi] Making a fake O2
bernie at innovative.iinet.net.au
Fri May 27 23:51:14 CDT 2005
On Saturday 28 May 2005 12:31, Marcello A. Belloli wrote:
> I have been trying to figure out how to make a computer run on its
> base fuel map, and not use the O2 sensor. I was wondering if it
> might be possible to send a signal that looks like perfect mixture
> all the time?
First; the "base" fuel map will tend to be slightly rich to avoid
excursions into lean that can rapidly damage an engine not built for
it. Read that as a warning.
> A signal that looks like no adjustment need to be made. You could
> put this in place of the O2, so you could see the fuel map output
> without correction. Is this possible?
It depends on the "computer". What it believes as requiring no
adjustment may be somewhat different to stoichiometric AFR. Some
deliberately run a touch lean at cruise, for example.
If all you want is for the computer to "see" a stoichiometric AFR
using a "normal" narrow-band sensor, then a constant-voltage source
may be sufficient. Some computers expect however to see a continuous
fluctuation between lean and rich; else they believe the O2 sensor
to be faulty. Simulating such is technically not very difficult.
Figuring out which your computer expects is another matter.
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
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