Ok, today I failed emmisions I was .91 on the Hydro Carbons, I need to be .80 or lower. I did just find on everything else. Anyway I checked my timing tonight and its 4 degrees advanced where it should be 0 degrees. Do you think setting it back to the factory setting would decrease it at all? Would retarding it a couple degrees help me get by?

Unrelated to timing but also emmissions related
My plugs are white probably from when it overheated, so I will replace those, I also checked my vacuum lines and found a couple very very small leaks. Do you think I should be able to get by with those changes and setting the timing? I know if I do the cat I am pretty much guaranteed to pass but i'm trying to get around that, as I want to do the full exhaust and would rather not dump money into a cat just to junk it three months later. If I still fail I can go to another shop that will stick a cat over the end of the pipe so i'm basically running 2 cats for inspection, that should definatly get it by, but I would rather see it pass on its own.

 

4* advanced won't affect emissions enough for you to be worried about. If anything it will help. I suggest you fix your vacuum leaks and changes your plugs, wires, and O2. Vacuum leaks can cause your car to run richer than you want. One cat will be plenty to pass and I would make sure that yours is not bad. You cannot run another cat at the end of the tail pipe because the exhaust gasses will not be hot enough for it to do its job.

 

Thanks for the reply.

I did fix the leaks, and i'm doing the plugs tommorrow morning, forgot to say that in there, but you think the O2 sensor might help, or is it just a good thing to do?
As I said, i'm just barely failing, so just a couple little things could be enough to get it by, thats why I was asking about the timing. You mentioned if anything you thought the timing would help with emissions, do you think advancing it another 2 degrees just for the test might help a bit?
As for the other cat I see what your saying, but the place that does it is where I used to work, and a few times ive seen cars that were just barley failing pass with the extra cat.
As for the cat being bad, I really don't care, I just want it to pass emissions this time, then ill get a "test pipe" and by the time the next emissions test rolls around i'll have a full 3in exhaust with headers and a nice new high flow cat. I don't want to dump $200 on a new cat to just rip it off in a couple months as I already said.

 

I understand your dilema. Leave the timing where it is at. I would replace the 02 just as a routine maintenence since these cars tend to get overlooked in that dept. I would not get a bosche one. I would go to your GM dealer to get one. The bosche ones make your car run a bit richer if you have the stock tune. Well you could always try the extra cat. I would maybe try to get some of that "always pass" stuff that you add to your tank. It has some goodies in its composition that will react with the bad stuff to make less bad stuff that will pass. That is my non-nerd way of going into it. A basic tune up with no vacuum leaks should solve your problems.