CC Qjet carb tune after removing AIR system? Anything special need to be be done?
 

Hey guys.

I've got a friend here in the UK here with me who has an 85 T/A, 305 with the CC Qjet. He plans on getting rid of the AIR tubes and smog equipment as it's not requird for our cars here in the UK (Emissions check is simple, carbed, no cat for is the spec cars older than 92 even if they have FI). I know the O2 sensors on the car should think it's running a bit rich once they are removed, but can I use the IAC to simply re-tune it using my dwell meter or do I need to adjust anything else? Just looking for options and things we may encounter once he gets his car out of the shop on Wednesday. I do know he plans to keep the EGR valve on the car, just not hooked up to anything to keep the check engine light from coming on. Thanks for any advice and assistance!

A.I.R. removal won't affect tuning. At idle, the flow only goes to the manifolds when in open loop, so the IAB isn't in play. In closed loop, which is when you adjust the IAB, the flow goes to the cat.

Re: CC Qjet carb tune after removing AIR system? Anything special need to be be done?
 

Thanks five7kid!

So we won't have to tweak anything, that's good to know. What is this I keep hearing about the car's thinking their running "rich" then? It's something I've keep reading about here and there on the threads. Something about a 100mv signal from the 02 sensor? is that something we'll need to worry about or am I overcontemplating things?

I've heard some of the EFI systems use an O2 adjustment assumption when A.I.R. is added to the manifolds under certain driving conditions (deacceleration, if memory serves), but that wouldn't apply at idle. It's more for emissions reduction than a tuning issue.