po171 - System too lean (Bank 1)
 

I keep having this code being thrown. Any idea what might be causing it? Did anyone have this code throw before?

Ken

do you have the stock fuel pump or is it upgraded ? and is the flash and mbc the only mods you have?

whoops...I got update my sig.

My other mods are Buschur TB with high flow cat, 272 i/e cams, UTEC, turboXS mbc.

Ken

is something wrong with the tune. What were your af's after the UTEC tune

The car ran fine before....

Here is my dyno sheet. My A/Fs seem to look fine.
One person suggested it might be a bad o2 sensor. :dunno:

http://gallery.evolutionm.net/data/5...an_resized.jpg

Ken

I've been getting it too, since I installed 272s, 680cc injectors and 255 pump. My AFR is 11:1 from 3000-redline????

You need to look at when your code was set. Look at the freeze frame data and look at what rpm's and how were the fuel trims at that rpm. It may sound like its chinese but that's the way you're supposed to check a code. My guess is that your idle is to lean.
Gil-superz

I got the P0171 code twice. I got that after installing the AFCII with APEX filter, with APEXi specific setting (comes with the filter) which lean out the idle and low rpm. I got the CEL on when the car is idlling one day after and in very low rpm another day. I just zero out the low rpm range of the AFC today and hope that fix it.

i agree with kcevo.. it just happened to me this week when i was playing around with the low throttle settings on my safc2.. so i just went back to zero adjustments under 3000rpms.. i'm gonna play with it again using my wideband this weekend.. cus my mpg is just horrible!

A friend of mine has the same code. Ever since he installed 272 in/ex. He also has 720cc, walbro GSS342 and AFC ect. His freeze frame showed 950 rpm so he was idling.

I totally dismounted the AFC and I still get it. Not the tuning because I have this before Turbotrix flash my car, I went to autozone to check the code again, the guy pull out a little booklet. For P0171, system too lean, It could be a/ MAF sensor, b/ Oxyen sensor, c/ vacuum leak.