Smog help (failed)

[tylerMM95]

Hey everyone! So basically i failed smog today..turns out my timing was at 35BTDC instead of 5btdc so i failed on that. Next i passed everything except N0x which was 3 times the max. So basically what i did before the test was change my thermostat to a hotter one because i heard that would help the cat work better and put on a new cat, but after figuring out high n0x is from high CC temp i feel like that was a bad idea. So what do you guys think i should do? I was thinking about just setting my timing to manufacturer's specs and putting in a cooler thermo to lower my n0x. My egr system is working fine and my 02 should be good although i was burning some oil for a while. I dont know about MAF or how to test it. Should i try to "clean" my 02 sensor? Any tips or what you guys would do would ve extremely helpful. Also i only have 7 days to smog it before my temp oper permit is expired...which sucks.

[geezer101]

Engine temp has little impact on exhaust gas temp. That is affected by engine tuning conditions and also means not just ignition timing. Make sure you have the right heat range spark plugs in it. Also make sure your leads and coil packs are nice and healthy. Good spark = cleaner burn. Now something a little stupid. If your combustion chambers are fouled up do not use a fuel additive. It will ramp your emissions especially this close to a smog test. You could run E10 for the test only as it produces lower emissions. Do an engine oil flush and change. The crap in the crankcase can impact emissions results as well so purging the contaminants out of the sump and block will help.

[camoit]

Or it could be the cat is just getting warn out. The will break down over time. But Nox is normally an EGR problem. Something is not flowing or opening up.