Failed Texas Emissions

[jtratza]

I finally got around to having my daily driver 1987 911 (124,000 miles) tested under the new Texas emissions standards for the Houston metropolitan area and failed the NOx test. I passed the others but couldn't meet the NOx limits which are 1,258 ppm at "high" speed (25mph at 1724 rpm) nor the low speed test (15 mph at 1525 mph) which is 1378 ppm. I tested at 1356 ppm at "high"speed and 1746 ppm at low speed.

The engine has a mass flow sensor but no cat. I removed it several years ago to relieve a little heat from the left side of the engine after I discovered that gaskets on this side of the engine seemed to be taking a hell (no pun intended) of a beating. The engine always passed the old standards but this was the first year the area has tested for NOx.

The plan is to put the cat back on tomorrow and drive it for a few days before retesting. The O2 sensor is new along with most other engine controls. This was done after I spent 6 months tracking down a mass flow sensore conection that was going bad. Only other idea I can come up with to clean the engine emissions is to have the injectors cleaned.

Any other ideas would be appreciated.