I just watched an Engine Masters segment on the Motor trend website which provided some really good info. They tested five different gauges to see how close they read. Also tested this: If you have a dead sparkplug and the cylinder pumps raw fuel into the exhaust does the AFR gauge read richer? No! Several other tests were also done. Watch the video to see the results, you will be surprised. Many other good tips also.

 

Do you happen to have a link? I can't find it.

 

Engine Masters | Watch Full Episodes & More! - MotorTrend
Hopefully that gets you there.

 

agreed solid watch. Also surprised leaks did not make a mahoosive difference

 

Yep, good information that is proven on the dyno. How many threads have beat on exhaust leaks being the cause of problems?
Hmmm, gets you thinking about it at least!
The raw fuel in the exhaust not causing a rich reading is also something to remember.
O2 sensors read oxygen content only! Does not care if it is bathed in raw fuel!
Something I think people forget.
Little nuggets of good information.

 

I find it rather surprising that their testing showed leaks having no negative effects....the same publication had this article out back in 2018 stating the very opposite.

https://www.motortrend.com/how-to/ex...nsor-readings/

 

Ha! That's funny, Steve Bruhl(?) ran the dyno on both occassions!
Seems like the latest dyno testing was all from 3000 rpm and up, no idle or cruise rpm checked.
Exhaust pressure blowing out of the leak instead of sucking air in?
Guess that's the thinking behind the latest test.
The earlier test has to be correct also.
Leaks are bad at lower rpm's especially, and more so when in a lower pressure part of exhaust flow.

 

Good info thanks!