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djw090
David Witham
Warwick UK
(115 posts)

Registered:
06/12/2008 11:20AM

Main British Car:
MGB 1974 and MG ZT 160 turbo 2005

AFR / O2 / Lambda Sensors
Posted by: djw090
Date: May 15, 2012 12:28PM

Some modern cars have a sensor before the cat and one after. I am planning to find a second hand sensor to use on my MGB. Are the before and after sensors essentially the same?

I may get 2 any way so if the before and after sensors are the same I could get them both from the same car. That might make the wiring easier.


DiDueColpi
Fred Key
West coast - Canada
(1366 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
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Re: AFR / O2 / Lambda Sensors
Posted by: DiDueColpi
Date: May 15, 2012 02:37PM

Generally no. The rear sensors are only there to confirm cat operation so they tend to be a simpler sensor.
Some sensors are air/fuel ratio monitors (wide band), some are simple lambda sensors, some heated, some not.
As well some provide a variable voltage , some provide a variable resistance and some provide a variable ground.
What are you connecting them to?


djw090
David Witham
Warwick UK
(115 posts)

Registered:
06/12/2008 11:20AM

Main British Car:
MGB 1974 and MG ZT 160 turbo 2005

Re: AFR / O2 / Lambda Sensors
Posted by: djw090
Date: May 15, 2012 04:57PM

I am connecting them to Megasquirt 1 v2.2. It is being used to control the spark and provide data recording.

The sensors will be used for data logging only. I am only inerested in narrow band at this stage but I had it in mind to use heated ones so they might be 4 wire. To a large extend it depends what is available used/cheap.
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MG four six eight
Bill Jacobson
Wa state
(325 posts)

Registered:
10/23/2007 02:15AM

Main British Car:
73 MGB Buick 215, Eaton/GM supercharger

Re: AFR / O2 / Lambda Sensors
Posted by: MG four six eight
Date: May 16, 2012 09:32AM

David

I highly recommend getting a new one as opposed to a second hand unit. O2 sensors do wear out and can give you false readings and nothing is more frustrating then trying to tune an engine with false imformation. When an O2 sensor is past it's prime, usually the ouput voltage will be lower and they will re-act slowly (poor cross count performance when cycling above/below 14.7 to 1 AFR)
Some of the GM sensors are fairly low cost and work well Mega-Squirt.

Bill



Edited 2 time(s). Last edit at 05/16/2012 03:20PM by MG four six eight.


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