rjwoolze

This is my daughters car and when I took it in for the emissions test, it failed. Should have known since the check engine light was coming off and on. During the summer she overheated it and I had to replace the radiator, water pump and thermostat. I used a 180 degree replacement thermostat. I did a test and she did not blow a head gasket. The compression on each cylinder is right around 150. It is not using antifreeze so I feel safe in saying that the head gasket is ok.

On the first test it barely failed.
First test at 15 MPH
HC Max allowed 131 Measured 98
CO Max allowed .66 Measured .79 Failed
NO Max allowed 1191 Measured 1041

First test at 25 MPH
HC Max allowed 122 Measured 77
CO Max allowed .56 Measured .72 Failed
NO Max allowed 991 Measured 821

I changed the air filter, Cat Converter, O2 Sensor, coolant temp switch and set the timing at 16 degrees. Check engine light still a problem. Found code 8.
Second test at 15 MPH
HC Max allowed 131 Measured 98
CO Max allowed .66 Measured .87 Failed + it is now higher.
NO Max allowed 1191 Measured 3175 Failed + 3 times higher now.

Second test at 25 MPH
HC Max allowed 122 Measured 64
CO Max allowed .56 Measured .78 Failed + it is now higher
NO Max allowed 991 Measured 2320 Failed + 3 times higher now.

Fixed code 8 by installing a new distributor (At least the light isn't coming on anymore) and put a header on it because the old exhaust had a crack.
Third test at 15 MPH
HC Max allowed 131 Measured 217 Failed + 3 1/2 times higher now
CO Max allowed .56 Measured 2.52 Failed + 3 times higher now
NO Max allowed 1191 Measured 2367 Failed but only a little less then before

Third test at 25 MPH
HC Max allowed 122 Measured 197 Failed + 2 times Higher now
CO Max allowed .56 Measured 2.54 Failed + 3 times higher now
NO Max allowed 991 Measured 2478 Failed + higher then the last test

Set timing again, put in another O2 sensor, changed oil, installed a different ECM, changed spark plugs and installed a new cap and rotor.
Fourth and final reading

Fourth test at 15 MPH
HC Max allowed 131 Measured 156 Failed but lower than last test.
CO Max allowed .66 Measured 1.42 Failed but lower than the last test
NO Max allowed 1191 Measured 2657 Failed + plus higher than the last test

Fourth test at 25 MPH
HC Max allowed 122 Measured 127 Failed but lower than the last test
CO Max allowed .66 Measured 1.52 Failed but lower than the last test
NO Max allowed 991 Measured 2278 Failed but lower than the last test

At this point I am at a loss. I have tried everything I can think of and it has only made things worse. Any suggestions would be appreciated.

Thanks



Modified by rjwoolze at 6:59 PM 4/16/2008

thesmogman

All three numbers are up so that would point to the cat. What are the O2 readings from the tests? At 25mph you should have none to very little O2 so the report should have 0.0 at the 25 tests or close to 0.1.

If you have high O2 readings the cat is not using the O2 to convert the other gasses thus high readings.

Let us know.