by David Ferguson on Sat Jan 03, 2015 10:03 am
If you have it, then you can run closed loop, allowing the ECU to compensate slightly if something wasn't tuned perfectly -- perhaps running at an unusual temperature, elevation. Or even compensating for slight mechanical issues (fuel or air filter starting to clog, different fuel blends). So the Lambda sensor keeps the engine running it best all the time.
The other reason to run it is when the engine doesn't run right. The Lambda is one of the first pieces of data we use to determine what the issue might be.
My general feeling is -- it's a must have, like air and fuel in the right ratio.
David Ferguson
Veracity Racing Data