Lean at idle Help

98BLKGT said:

Just got a wideband and at idle the car is very lean. It reads 16:1 (max) when cold and between 15-16:1 when warm. Where do I start?
I noticed my fuel pressure is low (30psi) but would that matter at idle?
Fuel ratio is pretty good at 14.4-14.9 cruising and WOT.
I heard that clocking the MAF might help but its a straight pipe with a pro-m 77mm MAF.

This is my meter at idle:

Click to expand...

You have 14 afr at WOT ......that's probably from the low fuel pressure

My car's running from 14-16 at idle depending on the temp and such, it runs a little smoother and quieter at 14ish.

I would bring the fuel pressure back up to 39psi (setting it without vacuum) and go from there.

Changing the fuel pressure doesn't do much in closed loop (everything but 3/4 throttle and up or so, it goes to open loop at WOT) since in closed loop the computer adjusts the injector pulsewidths to put in more fuel or take less out. Ever notice when you change the fuel pressure the first ride or so it seems alot snappier then after that it's back to normal? (I do anyway) because the computer readjusts the pulsewidths to compensate for the change in fuel pressure.