Engine running lean!:(

[tavnam]

I have recently made myself a custom 3" induction out of stainless. The O2 sensor is about 200mm from the rubber intake pipe n is fitted correctly too the pipe. The induction pipe has a 3" K&N pod filter that is located behind the frontnright fog light (where the water catch box was. It gets heaps of cold clean air where it is, but im havin problems with the left bank of the motor running lean. This has resulted in the fault code comin on (cruise light n S sports light flashing 1 after the other). The engine light is also on. I have had the fault code wipped twice n it keeps coming bak! I need a solution for this problem as i cant use S# or cruise while this fault is there n i really like the performance gain of the induction set up! I realise a tune would help this but i dont have large amounts of cash for a custom flash tune. Any1 had the same running lean problem or got a solution??? Im really over it!

[05GTLIBERTY]

not much u can do besides either put it back to stock, up the fuel rate or a tune

[Jaz]

After I spoke to chiptorque at a WRX club night about how they need to tune around changes, the intake, in particular the pipe size and volume was particularly susceptible to causing CELs and limp (safe) mode.

The ecu is calibrated with a hot-wire type AFM, a voltage runs accross it, using airflow to cool it and the ecu needing to put additional current into it to keeo the temp the same. The ecu works out airflow from that. Unfortunately It's dependent on the ecu knowing the given volume in the pipe at that time to work properly- thus your issue.

Unfortunately I think you have two options.
Leave you intake in and get a tune
Go back to standard intake. Fit a panel filter, remove the front side of the airbox off if you want, likewise resonator.