Re: 02 Sensors; WAS DML Digest V4 #538

From: mrdancer (mrdancer@camalott.com)
Date: Wed Apr 07 1999 - 20:04:37 EDT


From: Aaron <acolona@i-55.com>
To: <dakota-truck@buffnet.net>
Sent: Wednesday, April 07, 1999 12:31 PM
Subject: DML: Re: DML Digest V4 #538

> Does anyone out there know any way to cut the cat off your exhaust and
trick
> the oxygen sensor. >

This was discussed on the DML a coupla weeks ago. Here are some excerpts:

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From Jetmugg:

The 02 sensor "simulators" are used in the marine industry, where it is
impossible to mount an 02 sensor in the "wet" exhaust of many
high-performance
late model inboard boats. In fact, a friend of mine bought a new
MasterCraft
just last year, with a 350 horse 350 LT1 (Corvette) engine, which uses some
sort of electronic "black box" to feed signals to the ECM based on throttle
position, rpm's, water temp, vacuum, and who knows what else, in order to
determine the proper stoichiometric ratio being run through the engine. I
agree with the statement that it should be fairly straightforward for
someone
with electronic skills to create such a "black box" which would allow
someone
to eliminate the 02 sensor.

Steve.

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From Sandman:

The O2 sensor interacts with the amount of oxygen in the exhaust stream and
produces its own voltage form 0 to 1 volt, if I remember correctly, less
than 0.5v indicates a rich fuel mixture (greater than 14.7:1 air/fuel ratio)
& if the voltage is greater than 0.5v it indicates a lean mixture. I would
think it would be fairly easy for someone to create an o2 emulator, all you
would need is a clean 1 volt DC source through a rheostat. Using resistors
you should be able to reduce 12vDC (13.5vDC approx. charging voltage) down
to 1vDC into a rheostat (like a car radio volume control) & through a low
voltage meter (so you could monitor the voltage). More voltage = More fuel =
more power (to a point). just a thought ;-)
_________________________________

SandMan
proud owner of:
Flame Red 99' Sport CC, 318, FT-4x4, trailer tow package, Tire & Handling
package

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From John Steiger:

Yep, Sean Meldrum came up with an idea of how to do it. (Basically a
voltage divider that drops the voltage of the sensor down to "post cat"
levels to make it seem as if the cat were in place.) His design required
an O2 sensor in the exhaust, and I was looking to remove the downstream
unit, so I adapted his to a module that would replace the entire sensor.
Unfortunately, the heater circuit was a problem; the current melted the
insides of my module. :-) I have since had the sensor mounted
permanantly, so I will be going back to Sean's when I can get some time to
work on it.

  There is someone who sells an O2 simulator though. If I recall, its
about $50. (Its not for the front O2 sensor, its for the downstream
sensor, to fake the computer into thinking the cat is still there and
functioning.) The phone number and e-mail address of the guy who sells
them can be found near the bottom of the archive post at this URL:

http://csclub0.cs.fredonia.edu/Archives/dakota/9809/1488.html



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