All right to make a long story short. I had my car taken apart because I was replacing the clutch, so I decided to gut the precat(big mistake). Now I have to pass emissions and I'm failing by .15 on the hydrocarbons. I don't understand I passed with flying colors last time, I didn't think the precat played that big of a roll. I just replaced the spark plugs. It has newer wires, o2, fuel filter, air filter, oil. Is there anything I for getting? I don't want to have to redo the exhaust right now because I have other plans for it.

It's a 1990 GXL, and I live in nw indiana.

 

how old is your cat?
I bet you would pass with a new one.

 

You are going to need either a new precat or replace the oem cat with aftermarket cat. If indiana does a strict visual, you will need to go the oem route.

Here is a thread with my experience passing emissions in in Texas. We have no visual inspection.

Autozone part number for the cat I used is #38734.

Good luck.

 

I don't think they are very strict on the visual inspection. They just pop a mirror under there to make sure u have a cat.

You guys really think I need to replace the cat to pass? I'm so close though. The limit is 1.40 I went 1.55.

 

yes.

 

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/emission-testing-texas-style-465422/

Here is the link, complete with copies of my emmission testing sequence. I tried the alcohol trick airpump trick. If you are that close, you could try the alcohol trick. Buy a gallon of alcohol at Home Depot and mix it in the last couple of gallons of fuel in the tank. It reduced my emissions by 30%, but that wasn't enough for me.

Problem I see with your precat missing long term is that the main cat is probably designed for the pre to do a little of the work, especially on cold startups. I do not believe that the main cat will long survive without the precat. This is also why most aftermarket cats have a limited life as well.

Good luck