: 97 Catera, Emissions Questions

09-15-09, 01:51 PM
Hello, I would like to pose a question to any techs who might know about the Catera's emissions system.

I purchased a 97 Catera a year ago, with blown head gaskets. I replaced the head gaskets, installed a new radiator/thermostat, new plugs/wires etc.

After all this, I found out that the oil cooler was leaking, so I didn't have time for that job until recently - the car sat for about 6 mos. I installed the new oil cooler a couple weeks ago, and finally got to flushing the oil out of the cooling system.

At first, the car heated up quite high, and I simply couldn't get the cooling system to flow well. After flushing a not-insignificant amount of oil out, the car finally normalized its temps somewhat - enough that I cautiously took it to be emissions tested.

The car was, at the time of test, running about a notch/notch and a half above center (normal) temperature, and I failed on NOx emissions.

the numbers are as follows:

HC (g/km) max allowable: 0.5000 - my vehicle = 0.2550

CO (g/km) max. allowable: 9.3200 - my vehicle = 4.5070

NOx (g/km) max allowable: 1.24 - my vehicle = 1.7429

the graph shows that where things spiked was particularly around 80-85 mph, as well as under sharp acceleration (no surprises there).

Any useful insight would be much appreciated,