The wagon failed emissions today on HC and NO. Readings in grams per mile:
Reading / Standard
HC 1.3753 / 0.8000 Fail
CO 4.4606 / 15.0000 Pass
NOx 4.1198 / 2.0000 Fail

I was surprised the readings were so high as there are no running problems. It starts and runs very well. Two years ago I had higher HC and NOx. I replaced both the O2 sensor and cat and got good numbers (0.18HC, 0.79CO, 0.24NOx). Since that time I switched to a V15 cam - not hot, about the same duration as a stock Chevy V8. The car ran well with the new cam so I assumed that the mixture was correct. The AMM should just give fuel at the same ratio for the increased breathing, right?

I'm tending to think the O2 went bad. It's only been on for 2 years/21,000mi though. The last sensor was obviously bad. On that one testing with the multimeter showed no continuity, open. I checked this one tonight and got zero ohms resistance. I'm trying to recall but I believe there should be some measureable resistance across the sensor. The other thing that troubles me about this sensor is that unplugging it showed no change in idle speed or quality.

BTW:
Timing is fine.
Air box thermostat removed - cold air only
No vacuum leaks

Ideas?

mormit
--
85 245DL 260,000mi V15cam 'Old and Rusted', 02 S40 'New Hotness'