Quote:
Originally Posted by sixto
Sorry, wrong direction. High NOx indicates faulty EGR.
[edit] Actually it indicates high combustion temperatures. EGR keeps combustion temperatures in check but the engine might be running too lean for other reasons which I think is what you tried to resolve by enriching the mixture. Do the tests end with the car at speed or does the cycle include coastdown?
Sixto
87 300D
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O2 Sensor was replaced prior to test in 2005, so 4 years old. Seems to be sending feedback to Jetronic okay, but plan to check O2 Sensor electrical connection point later today.
No EGR on this model.
California emissions test, I think they collect all measurements at specified velocity (15mph & 25mph).
Yea, I've read ALL the material from the experts here on NOx formation at 4000F - peak combustion temperature. If I am unable to get NOx undercontrol via the related Jetronic adjustments, I'm afraid I'm going to have to retard timing through the changing of that little resister (I'd appreciate it if someone can direct me to instructions on that).
What I still don't get is the significant reduction of CO, and whether that has a positive or a negative impact on NOx formation.