I just need some advice with my car because I need to pass aircare. My car is an '87 TII running a Microtech LT8s with a full emissions removal. I figured that my car was running rich at idle, and was confirmed when I failed the smog idle test. I ran the Aircare test just with an aftermarket cat and methyl hydrate in the tank (5 gas:1 Methyl Hydrate), and my car passed the driving test with flying colors, but horribly failed the idle test with the readings of 1500ppm HC over the max allowable of 328ppm and 3.92% CO over the max allowable of 3.81%. I had just changed the plugs as well and the old plugs looked very bad with a nice layer of carbon buildup with the presence of oil..... Should I just get the idle afr tuned via the ecu or are there other things I should be looking at?

Trailing plugs on the left, Leading on the right.

 

Do you have an airpump hooked up to your cat? What is the idle AFR?

 

I didn't have the airpump hooked up to the cat at the time of the smog test. I don't know the afr numbers. I've been trying to figure out why my gauge isn't getting a signal.

 

I'm assuming the LT8 has some way to tune idle fuel. Even without a functional wideband, you can make adjustments and gauge the mixture by how smoothly it runs. I've found the 12.0 to 13.0 AFR range to be the smoothest. Take it as lean as you can without causing misfires / stumbles, and you should drop your numbers.

 

Thanks, but I am thinking that I should take the car to a shop to get the ecu tuned because I don't feel like messing anything up :p