Ok so living in arizona i'm stuck doing emissions...how retarded, i took my camaro down to the testing place in mesa and i was hoping to pass like everyone does, i go thru the tests, then i get that nice paper with a fat FAIL mark. They gave me a list of possible problems and i've gone through them and its still not fixed, first of all i failed on the oxides of nitrogen test by .06! there should be a bit of margin for error there. SO i took it back to the shop and popped the hood, i checked the paper and it said " over advanced/off idle timing" so i check that, it was down at the 4 PAST the zero mark, but when you look it up on all data it says that it needs to be at 6 below top dead center. I adjusted that, went home and had a friend of mine check my EGR valve, apparently it was broken, so i went to checker, got a new one, and put it on. Thinking i had a done enough to drop my results by .06, i went back for my free test, which royally pissed me off, not only did i fail again. but the oxides of nitrogen jumped by .30! What can i do to fix this and get my car through emissions? If i retard the timing again would that help? because it obviously did something.

Also i was thinking about changing out my cat, its stock from 89 and im wondering if i get a new one if that will help my scores.

Any suggestions?

 

First, did you check the timing with the brown wire disconnected? If you didn't, the timing is nowhere close to right.

The terminology typically used is "before top dead center", or "BTDC" for "advanced" timing, and "after top dead center", or "ATDC" for "retarded" timing. Too advanced typically leads to high NOx readings, but too far retarded will also cause problems.

Disconnect that wire, set the timing to 6 degrees before top dead center (to the left of the zero mark when facing the engine from the front), and see what that does.

 

yeah we did it with the wirew disconnected, ill check it again to be sure, thanks for the tip

 

This is a good emissions reference: http://www.autoshop101.com/forms/h56.pdf

 

ok, heres my plan, if i throw a new cat on andretard the timing back to where it was do yuou think i could get it down to pass?

 

If you still have the stock 20 year old cat on there, yes its wore out. Replace it with a Magnaflow.

 

where do i pick one up? It sounds dumb but when i looked it up their website they didnt have a 5.0 v8 for the 89 up there, or i just missed it, and when i type it into google it comes up with things like autopartswarehouse which i dont think i want to order from.

 

autopartswarehouse and rockauto.com are both pretty good.

 

a local exhaust shop should be able to put a decent three way cat on there to get it passed emmissions, also t a vacume gauge in the egr to see if it gets a signal to open at part throttle while driving if not fix that and you probably wont need a cat

 

how to i check that? hook the gauge up and hit the gas and see what it reads? wat do i do if its not getting that signal?