Not all, but 99% of Lambda sensors work by giving out a voltage which they generate according to the oxygen content of the exhaust gases. But in order to do this accurately they have to be at their working temperature. There are some differences from one manufacturer to another and also in production tolerance, but they all give stoichiometric mixture at 0.5 volts. The working range is 0.2 volts to 0.8 volts with 0.2 volts being a very weak mixture and 0.8 volts a rich one.
Just how rich and weak these extremes are will depend on the sensor and whether or not it is up to working temperature, but 0.5 volts will be right in the middle every time. If you have access to a CO meter it should be a simple enough job to set your mixture up and take a voltage reading from the lambda, then richen and weaken and note the results in terms of voltage change from the sensor.
Having calibrated the sensor you can then use the voltage readings to set up your carburettor/injection system of whatever. You can buy lambda sensors from breakers yards but the main problem here is getting them out. After a few years they tend to rust into the pipe and you strip the thread on the Lambda. New sensors aren't that expensive, the most you'll pay is around £70 retail.
The thread size is common being 18x1.5mm and you'll need to make, or have made, an adaptor boss to weld into your exhaust manifold. This size just happens to be Pinto spark plug thread so if you don't want to leave the sensor in, you can use an old spark plug to fill the hole. The place to put it is on the join of the primary pipes, as close to the engine as you can get and still
read all of the cylinders.
The voltmeter that you use needs to have a fine setting in order to read 0.1 volt changes.A digital high impedance voltmeter is common enough in the electrical world and the chances are you can borrow one if this isn't the sort of kit you normally have.
Buy the lambda from a breaker's yard and you can start mapping/setting up for around ten quid.l …….More