A/F Mixture and CO% setting

wcc · 04-06-2007, 07:05 AM

I picked up CO gastester (Gunson) and I have a couple questions. Hopefully, someone here can help me out...

According to the book it says to unhook the O2 sensor, set the CO to .6+/-.2%, then hook up the O2 sensor. Ok, but what if I don't want to bother with the O2 anymore and just leave it unhooked. Isn't .6 a rich condition? So what should I set my CO to without using a O2 sensor. .8, 1, 2%?

The car is stock with stock exhaust system.

RarlyL8 · RarlyL8's Garage

Set your CO at 3%, leave the O2 sensor unplugged and see if that works for you..

wcc · 04-06-2007, 11:42 AM

Cool, that's what NathanUK said in another thread but wasn't sure with me still having the CAT. That's what I'll do...

Thanks!

wcc · 04-13-2007, 08:56 PM

Hey Brian, I just wanted to say thanks. When it comes to this CIS stuff you are great resource to this board. Don't EVER leave! I set it to 3% today and it's amazing what a small change can make.

Thanks Again!!!

RarlyL8 · RarlyL8's Garage

As you contiue to learn your engine and tinker with it you will find a "sweet spot" in the initial CO setting where your idle will be spot on smooth. 3% is just a good place to start. I think mine ended up at 2.7% if memory serves. Summer weather with the heat and humidity change the density of the air and can cause the occillation to return when set at 3% on my engine.

There are those who are not as thrilled with my banter as yourself but I've been with Pelican for around 10 years and have no plans to leave.

Oh Haha · 04-14-2007, 06:26 PM

So Bill,
How much difference did you see in the performance after the change?

wcc · 04-15-2007, 01:13 PM

Quote:

Originally posted by Oh Haha
So Bill,
How much difference did you see in the performance after the change?

From going from just disconnecting the O2 to where it's set now, I can tell a difference. But from where it was set last time you were here it's probably all in my head. But it really does seem to sit you back just a touch more when the boost comes on and it feels smoother throughout the RPM range. Honestly I can say the runs, drives and idles better then it ever has.