UOAs are cool, anyone use Smog Inspections for....

Joined
Sep 8, 2008
Messages
820
Location
Tennessee, USA
....deeper engine analysis? I'm considering having my Volvo smog checked just to see what's going on with an external diagnosis of burn quality. I wonder if anyone offers a technique such as removing an O2 sensor and plugging into the exhaust stream pre-cat? Yeah, having the sensor out of the stream may cause the car to run wrong,....any ideas?
 
Joined
Sep 23, 2007
Messages
8,598
Location
Florida
race engine builders would sometimes weld extra O2 sensor bungs in various parts of the exhaust system in order to use exhaust sensors in the entire system. Once the tests are done, bolts are installed in the O2 sensor bungs Taking your O2 sensor out will cause your engine to run in "Limp-home" mode, and the ECU will cause the engine to run too rich. Therefore you will probably need to run the multiple O2 sensor bung method.
 
Joined
Sep 13, 2004
Messages
1,904
Location
Canada
May as well fit an EGT sensor (pyrometer) on the exhuast stream as well. Testing under standardized conditions should give you a baseline EGT, against which, you can compare against engine manufacturer EGT limits, and against your baseline for trending reasons. A gradual reduction in EGT margin is to be expected.
 
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