I have gutted cats. I'm trying to pass emissions w/o cats...or at least get my car running properly before I do put on cats.

I failed emissions again on my 2nd attempt, I improved my HC and NOX by a lot. Since my first attempt I have cleaned the K&N air filter, new spark plugs(AC Delco), seafoamed, changed PCV, disassembled and cleaned out entire intake/throttle body, and made sure EGR was working.

My CO is still way too high. I did some searching and found that high CO results from rich air/fuel mixture. I have 24lb. SVO fuel injectors and my car is basically stock minus catback. My injector constant is set at ~25.3. So, I'm thinking my problem could be the fuel injectors are still delivering too much fuel. Should I try increasing the injector constant? What else can I do to lean out my air/fuel ratio? I can burn a new chip if needed. I'm going to hook up the AutoProm tomorrow and record some data, hopefully you guys can help my decipher it though.

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Start by dropping your fuel pressure. Don't go below 26 psi with those injectors.

 

honestly, your only real MAJOR problem is CO, which is what the catalytic converter is primarily designed to reduce.
NOx is another big one, but you are already pretty clean there, which means your EGR is working great.
how is your O2 sensor?
if it has seen better days, replace it.

a simple cat addition will easily pull you down below the limits however

 

as RED_DRAGON_85 stated Id start with the O2 sensor if its a one or two wire sensor go to a 3 wire self heated or a wide band sensor and that should help bring the CO levels down

 

I'd start by putting cats with guts on.

Doesn't make any sense to run gutted cats. None whatsoever.

 

a rich air/fuel will reduce nox

lean out your fuel and your nox will go up.your already over the limit.

your wasting a lot of time,go on ebay grab 2 cheap catco cats for $45 each.clamp or have them welded on,get the sticker and then do what you want.

 

Put a good, high flow cat on. You'll never miss the 2hp (at most) that you'll lose.

If you really want that 2hp back, use flanges on each end. And put matching flanges on your gutted cat too. Then you can swap the real cat on for emissions testing, then swap to the gutted one for the rest of the year.

That is most likely the quickest & easiest way to pass testing.

 

Yeah I'll probably pass with new cats, but I'm still concerned over the air/fuel mixture being too rich which could cause the new cats to go bad quickly. New cats will only mask the problem, not fix it. I'm looking for how to fix the rich air/fuel mixture.

 

lol.. the freakin' EPA is gonna shut us down..haha... ok well ... what about messing with your timing, at least just for the test, but yeah I would say you'd have to get new calibrations for your injectors... you may want to ask Kevin for advice, I think he's pretty good at this crap..

 

Get a O2 gauge and fix it if you're worried.

 

tic toc... clock is ticking... get a temp fix so you can get your tags and then worry about the problem... I don't how emission laws are in AZ, but here in Cali you have 2 extensions IIRC, and then you're either screwed or screwed ... I think you either have to take it to a shop or to a ref in order to either get a fix or an extension... don't know this last time that it didn't pass the sniffer test, I ended up developing other problems and didn't bother to troubleshoot them, it has something to do with the Tranny... but yeah my advice is if the CATS will get you your tags then by all means jump on it...

 

Well I passed after new cats.


But now I've got a new problem, the starter...

 

DAMN!!! was all that just the CATS? no other mod to pass the test?

 

man that stinks that they actualy smell whats coming out lol. here in pa they do a visual. It just has to be there and look like it works. But in my case i keep it under 5000 mile a year and its exempt. i have no emissions stuff on my car including no cat at all.

 

And I'll bet your car is no slower than before, but does run better now!

 

Yeah just 2 new cats everything else exactly the same, exact same station.

 

Could it be that gasoline engines have nasty emissions and that cats magically (scientifically) fix it?

 

No real time problem in AZ. My car sat for about 2 years with no tags at all, not even registered.

 

Hey your not too far from me, i live about 20 mins west of gettysburg, but Yea i love Pa emission laws franklin county is strictly visual checks and if its in a emissions county and its older than 95 its still visual. My 89 Z24 had never had operating cats on it and i plan on yanking the cats outta my 15th Trans am once i get it running cause ive seen too many cats get clogged working in the shop. And as long as i keep my inspection and emissions license up to date i wont have to worry about passing