Gatsby

iTrader: (7)

So I've been having a rough idle after my cam swap and I haven't had it tuned so no biggie. A few people told me to try turning the throttle body set screw 3/4 of a turn to "crack" the blade open a hair. I did that and the TPS relearn procedure.

It didn't help at all, a single bit with the idle.

I checked the SES light and of course I have P0300 (random misfires) which i hear is normal after a cam swap, but I also have the two codes in the title which are "running lean" in both banks.

Could the cracked open throttle cause that? It's still metered air so why would it run lean? Is it that the throttle is letting in air but the PCM thinks it is closed and is fueling it accordingly thus making it lean?

Or do I just have some other issue? I checked the visible hoses and nothing is overtly cracked or holey.

Any insight? Thanks all.

DaveX

Cracking the throttle blade won't make it run lean. But it changes the airflow at idle, which needs to be adjusted after a cam swap. But it needs to be adjusted in the computer. Simply cracking the blade a hair is a shot in the dark. It is most likely running lean because it is flowing more air because of the cam. The computer will try to get it back to stoich on it's own by adding fuel. But the computer can only adjust it so far without being re-tuned and if it adds as much fuel as it is "allowed" to do and it's still lean it throws the code. You need to get it tuned, there are several tables that probably need to be tweaked for idle, driveability and WOT. It's also likely very lean at WOT, I wouldn't recommend running it hard until you know it's right.

Gatsby

iTrader: (7)

I haven't been running it WOT for that very reason. I really don't know enough about tuning to know what's safe, but I'm learning what the tune can and can't fix. I never thought about it running lean because of the tuning not providing enough fuel. Thanks for the tip.