lean idle issue.

[Tuner.87]

OK i have been searching for the past 3 hrs with no luck so i hoping i can get an answer or linked somewhere. I installed the lexus Maf, and 550 injectors, walbro fuel pump with 12v mod, and aeromotive afpr bypassing the j tube. I have the stock idle screw set all the way in that i can get it witch looks to leave about half of the unmetered air chamber open. I have the fuel pressure set at 40 with no vacuum. I still seem to idle at 18:1. I know this is way lean. I cant seem to fix it. If i add fuel pressure im afraid when driving it will be too rich. when it was set between 45 and 50 it idles at around 17:1 but at WOT it was pig rich at 10:1 but cruising was the same at around 15. I havent tried wot throttle sense i turned the pressure down to 40. I have a way of tuning fuel but i have not yet installed but I dont see any means of tuning the idle with it and want to figure this oput first.. Any help would be great. I Have seen many post with ppl having the same issue but no one has said weather they ever fixed it or not. Could it be my ecu being bad?

Mods are 3 inch turbo back, boost at around 12 psi, and K&N Filter.

 

[jetjock]

Crack me up about the K&N.

Some engines need even more of the lower chamber blocked. It's one reason there was an aftermarket screw. That said what's Vf doing? What's the average voltage of the stock O2 sensor? And you know that, as long as the engine isn't into lean misfire, being lean at idle is actually not a bad thing right?

 

[Tuner.87]

i have read that a little lean is fine but i didnt know if 18 was safe. i havent checked the Vf yet. What two ports am i suppse to check again? How shall i go about checking the stock 02 sensor? Sometimes the car does want to die then bring it self back up. It kinda sounds like it as a slight lope or mis when idleing. I'm just starting to learn the tuning portions of all this so i would ask that you bare with me a little. Im a hands on learner so once you explain something i need to go do it to understand it. thanks for what yuou have given thogh. Is this screw still for sale or any other way of doing so. I seen a post somewhere and they siad it was 100 bucks and hopefully the guy still has some. Info?

 

[jetjock]

Voltage on Vf and E1. O2 sensor can be checked on either OX and E1 or Vf and E1 when T and E1 are connected and the throttle is off idle. For O2 measurement the meter needs to record and average. What you're doing is checking for pirate air.

Being lean at idle is completely safe. Truth is the engine can be run lean of stoich (200 EGT degrees or so lean of it) up to power levels of about 75% without worry. It's done all the time with aircraft engines including turbo ones. Above that level is a different story. And lose the K&N...

 

[Tuner.87]

ok so should i try to track down the 100 screw or no. anyone know where i can find it?