Very good responses gentlemen!

To Duke-I have seen OBD-II converters get above 14.5% but rarely did I see converters that have a KE fuel system in front of it get over and above this mark. Maybe you can obtain this value with a brand new OE converter but one with mileage might be rare. Is the low NOx value on the 560 attributed solely to the catalytic converter? I was under the impression that the majority of NOx is produced during the combustion process due to high temperatures. An efficient catalytic converter can and does reduce a good percentage of NOx, but what percent? Since it is unable to reduce all NOx produced are there other methods, or devices that assist in the reduction of NOx gases? I was under the impression that a small amount of inert gas being added to the intake system would be, or is, the greatest contributor to the reduction of NOx gases because it helps lower the combustion temperature. If you feel I am not completely clear with NOx gas reduction maybe you can give some direction for some good reading material concerning "Catalytic Converters."

While I have that in mind I would like to ask any of our 380 or 500 vehicle owners who have been through the California “Enhanced Emissions” test to post their test results for comparison purposes.

I am very curious about the differences between the 116's/117's with KA-Jetronic versus 116's/117's with KE-Jetronic


To John H
15 MPH:

CO2 - 13.5
HC - 187 (126 max allow)
CO - 1.67 (0.79 max alow)
NO - 460 (1316 max allow)


25 MPH

CO2 - 13.7
HC - 166 (101 max allow)
CO - 1.31 (0.59 max allow)
NO - 417 (1112 max allow)

My experience: your CO2 is slightly low, near or slightly above14; CO value measured after the catalytic converter, near O%; the HC, 10 to 50ppm. The CO and HC are somewhat proportional, increase/decrease the CO mixture and the HC’s follow to a point at which time they will become inverse of each other.

So, high HC, CO with low CO2 indicate to me you need to confirm the engine specifications are set to a T. I suggest an O2 sensor for grins, never hurts and you may be surprised. After all these are addressed than you may want to perform a catalytic converter efficiency test. Good general automotive repair books should help understand this basic test, it works great.


Have a good weekend all!