Your BMW is a non-EGR equipped vehicle which means most of the emission
reduction load is placed on the Catalytic Converter. The important thing
here is this... if in fact the CAT is damaged, it is important to ensure a
pre-existing problem is not the culprit. You don't want to damage the new CAT. A CAT melt down usually occurs due to high CO (Rich Fuel), old age, and
extreme heat. It is recommend to suspect the CAT after a complete emissions system diagnosis.
posted by SmogTips Support
