I just failed emmisions in mMaryland with my 94 LT1. I have gutted the cat converter and removed the air pump and EGR. Had it programmed to disable or delete the pump and EGR. My results are the following

State Standards My readings
HC 1.8000 GPM 3.0743 GPM failed

CO 30.0000 GPM 10.4270 GPM pass

NO2 2.80000 GPM 1.8146 GPM pass

I have new plugs, wires,02 sensors prior to the test. car runs good but could be better on gas mileage. Any quick ides as to what to check. Should I clean or replace the AIC sensor.

Thanks

 

You think it just might have something to do with the gutted catalytic convertor?

If I had to guess, I'd say you have a leaky injector dumping extra fuel into the exhaust = unburned HC. Might have passed with a cat. The cat converts the HC to CO2 and H2O..... that's why it's there.

 

I assume you are trying to figure out how to pass of HC? Well, without a cat, it is going to be difficult. Air pump, not really needed to pass, but the only car i know that runs that efficient without a cat is a Ferrari over 2000-3000rpm. You could lean the hell out of the mixture, but the NO2 would go up and possible misfiring. It doesn't look like you have much room for more NO2, though. Now if you kept that EGR................ Hmmmm. I will think more on that, but i think your only option would be to, dare i say, put on some emmission control devices. What thermostat do you have in right now? Possibly a MSD box will help?????? I know MSD will send out the multiple spark at idle, but i don't know at what RPM it cuts out.

Good luck, man. I personally don't know anyone that has passed emmission requirements without ANY emmission control devices.

 

What are some of the LT1 emmision readings from people on this site that passed.

I really did not want to put a new Cat on but if thats what I have to do then thats what I will do to keep the emmisions people happy and off my back.

 

Different states use different standards, different test methods, different pass/fail limits, and different units of measurement.... good luck.

 

when you get your cat put on, don't forget to get them bolt in, instad of weld in
leo