IROC.CAMARO86

Just came back from 2g station and failed 3 of 4 categories.
Problem/Result/Requirement
High Speed CO/2.53%/1.20%-Lower
Idle Speed HC/1265/220-Lower
High Speed HC/223/ 220-Lower

I went there knowing that the timing was a little off, Went by ear since previous owner replaced stock timing cover with aftermarket, and the current one does not have any notch/marking to show TDC.

HELP PLEASE!

Pat Hall

iTrader: (31)

Yeah you'll obviously need to figure out some way to get your timing set accurately. Either put a stock timing cover back on there or find a bolt-on, aftermarket tab that's accurate. Once you're able to adjust it properly, set it around 6-8 degrees BTDC. The other thing that helps immensely is to make sure you have a good, functioning catalytic converter. I live in UT, and the emissions standards/limits here are exactly the same as what you listed. My motor is newly rebuilt and I was exceeding the emissions limits not by a lot, but just enough to fail. Reason being is I eliminated the cat and had a straight pipe on there. My CO's were in spec, being around .60, but my HC's were about 240. All I did was put a good cat on, didn't even hook up the AIR to it, and here was my readings with a functioning cat. CO's at idle-0.0, CO's at high speed-0.0, HC's at idle-33, HC's at high speed-8. I was astounded at how much difference it made! Doing a fresh engine oil change helps clean them up too. Also make sure your motor is good and warmed up before they run the test. The hotter the better. If you can't get it to pass after doing those things, then you probably either have shot fuel injectors that are leaking and making it run way too rich, or you have a lot of blowby in the cylinders due to engine wear. I put the old straight pipe back on the weekend after passing the test. I don't mind slapping a good cat on there once a year to get through the test! But yeah, if you're just ballparking your timing and your cat is possibly shot, that can cause it to fail by a landslide.

ASE doc

A new cat will lower HCs about 400ppm. Not enough to solve your problems. Your too rich but not by much. Your timing is too advanced, causing the high HCs. Didn't I already give you a detailed description of how to fix this car to pass emissions in another thread? At any rate, HCs are unburned fuel, generally caused by either a misfire of some kind. Some HC is normal and the engineers intended for these HCs to be burned off in the exhaust manifolds. In order for this to happen, the manifolds have to get hot. If timing is too advanced, they don't get hot enough and HCs go up. Retard timing 4 degrees. This will lower HC considerably. The AIR system lowers HCs by injecting fresh air into the manifolds when the engine is cold, and by injecting air into the cat when the engine is warm. The injected air reacts with the unburned fuel converting it into CO2. I have gotten many cars through DEQ with dysfunctioning AIR systems. But if yours is marginal, you may need the AIR system to make it happen.

CO is partially burned fuel caused by rich fuel mixture and/or poor combustion. At your level, a new cat will get you through the test. A tune up, new air filter, and injector cleaning wouldn't hurt either.

Pat Hall

iTrader: (31)

Thanks for posting that ASE doc. I never can remember which symptom affects HC and CO. I know timing and spark advance affects one of them, and fuel mixture affects the other, but I always forget which is which! My motor is so new that's probably why the AIR system not functioning really made no difference whatsoever. I also deleted the EGR valve both physically and in the PROM. That way I don't ever have to worry about the dreaded code 32 that's such a PITA to get rid of!

bobbyk3lly

wow that sucks, too bad you didnt know anyone who wouldnt just give you a emissions sticker