Okay, passing smog has become a bloody nightmare. First she failed across the board, high NOx in particular. I dove into the intake manifold and replaced all the vacuum lines, new intake manifold gasket, new DISA gasket, etc.
Also replaced the O2 sensor (she was throwing a code). CEL is being a persistent bugger and still insists that I need to change the O2 sensor, even after being cleared.
Since my temp plate had run out, I needed to try smog again so at very least I can fail and get an extension. Sure enough I failed.
NOx is way down, well within spec (yay for new vacuum lines!). However HC is way up, failing both tests and now I am a "gross polluter". Shove it, Al Gore! :cool:
I am assuming I've always been running rich, but vacuum and manifold leaks were helping everything out by leaning the mixture a bit.
To be specific, I'm now ~13.5:1 rich of stoichiometric (14.7:1), leaving lots of incomplete combustion and making Gore cry.
Here's where it gets interesting. I threw a diagnostic computer on and it told me there was a short between, I believe, pins 70 and 71 on the DME, which relates to the O2 sensor circuit. The PO had the DME replaced following the dreaded rain gutter short, and said he'd had a CEL ever since. I suppose it makes sense that the DME itself could be bad, causing a short, and thus getting false readings from the O2 sensor, making it richen the mixture erroneously.
Thoughts? I've got one month to fix this problem, and no more extensions after that.
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