hpservertech

Well went to get her inspected this morning and failed the emissions test. Looks like the HC & NOx are too high.
HC: Standard - .8000 grams/mile Mine: 2.1523 grams/mile
NOx: Standard - 2.000 grams/mile MIne: 4.8705 grams/mile

For HC the only things that are possible I think would be O2 sensor, vacuum leak or cat. I installed new plugs last month so I dont think that is it.

For the HOx only thing I can think of is the cat again.

Anyone have any idea's? Im going to take it to the shop in the morning to have them put a new O2 sensor on, I can't get it to budge for me.

Any thoughts would be great.

Funn944

High NOX can be an indication of a lean condition, or high cylinder temperatures.

inactiveuser92616

For some reason your catalytic converter is not working correctly. Either the catalytic converter is worn out, or the mixture is off. The car needs the O2 sensor to keep the mixture in the narrow range that the cat converter will actually operate in.

On an off chance, you may also want to check and make sure that there is nothing dragging in the driveline (brakes, axles, bearings, weak cylinder) that could increase your rolling resistance. By the measurement units, it sounds like they had your car on a road dyno with the wheels spinning.

What were the other gas numbers on the emissions report?

hpservertech

Correct it was on a dyno. Was funny watching the guy try to get it into 5th.

CO: standard is 15.0000 grams/mile Mine was 10.2635 grams/mile
CO2: mine was 378.5454 grams/mile but isn't used in MO.

nickg

overrich....get a new o2 senser first(the right one, NOT universal) check fuel pressures, hope that you did not go too long like that because the cat will have been damaged

hpservertech

nickg: What do you mean by the right one? There is already a cross refrence to one that goes into a Ford, just doesn't have long enough wires or the Porsche connector. Universal's are good, but not something I am going to use on this car.

So it's either the O2 sensor or the cat...is that the feeling?

quinnfiske

I am going through this crap with my 951 right now. Failed HC and NOx. Put a bottle of Techron in 5 gal of gas and drove it hard about 75 miles. I was hoping it burn off carbon deposits and essentially lower compression ratio. Could'nt find any vacuum leaks. Pulled 16.5 mm Hg on a vacuum gage. Changed O2 sensor (mine came right out). The "right one" has the correct connector on the end. The cheaper one has to be spliced in.

Now I passed NOx but failed HC again and CO now fails. I am going to turn my attention to the AFM and check resistance values on temperature sensors. My cat has 175K miles on it.