I just installed a wideband in the car and the idle seems to be running lean in my opinion.

Mods: Pettit ECU, intake, full exhaust w/highflow cat, upgraded IC

A/F ratio at idle: 16.5-18

During normal driving it hovers around 14.7-15.5 and at WOT its somewhere around 10-10.5 @ 12psi

I thought it should be sitting around 14.7 at idle as well. Is this not correct? If so what would be wrong with this setup?

 

Mine idles around 17:1. If the idle is smooth, you can go as lean as you would like.

10:1 is very rich, BTW.

 

You're not actually running at 16.5 afrs, what youre seeing is port air being injected into the exhaust stream just after the exhaust ports.

 

Ya, as long as it idles well, don't worry about it. Congrats on the wideband, too, a vital upgrade imo- especially if you can run your ecu closed loop.

 

Only when u boosted it matters more, I have the aem setup, and it read pretty much same as yours but on boost it hover aroun 11.5 to 12., with 15lbs of boost. Also check out the pwer FC sub forum and do a search for your post title.
Khris

 

Oh right I totally forgot about the air pump.

I know 10:1 at WOT is very rich but seems to be how the Pettit is tuned. If I run anywhere from 10psi to 13psi it starts around 11:1 maybe around 5,000 and goes down to 10:1 as I get to the redline. I really don't mind, just give me this safety margin I guess.

Thanks guys!