Hey guys, Im still getting the following code..

P0171 - Fuel Trim System Lean bank 1-B, Drivers side

After starting the car up, and allowing it to idle for about 2 minutes it immediately idles like sh*t, and throws the lean code.. The car runs fine in open loop, but once in closed loop, its runs like crap.. (this is with both the stock and modified tunes)..

Current mods on my 2004 Z06 with 16,500miles:
Long Tube Headers, Tune, Vararam Intake, Crane Dual Springs, t-stat..

I removed the plugs, and found the drivers side to be completely black, and the passenger side spark plugs to be in good condition.. Im going to guess that while the car thought it was running lean it was running real rich (correct assumption?)

-I replaced the 02 sensors, code still present..
-I swapped the 02 sensor lines, and the code pops up on the drivers side no matter what.. (so the lines are safe, no issues with wiring)..
-I replaced the MAF, code still present..
-Swapped coilpacks from drivers side to passengerside, code still present..
-Opened up the ECU, no water present..
-No leaks in the intake, looks good..
-Had a compression and leakdown test done on the car, results were perfect, motor is in great shape..
-I recently had my shop reflash the ecu so that I run the stock program after the header company suggested that it might be my tune.. Code still present..

I unplugged the front 02 sensors (so the car runs in open loop) and drove the car around and aside from running really rich, the car has no issues.. With the 02 sensors plugged in up front, the car will stumble on its on with just a little throttle application, throws the lean code, misfire codes every so often, and seems like it wants to die.. At WOT, the car runs like crap..

Tonight I removed the drivers side header, and found the following.. I was just wondering if this was was a large enough crack to cause a lean code?

I really don't know what else to check after this (maybe injectors?).. There was no soot around the header/head connection, but to ensure its not a leaking gasket Im replacing the drivers side once I can get my hands on one... The headers have been on the car for over 6months, and never once gave me an issue and as far as I know were not removed during the valve spring repair..

I have been told that it was probably an exhaust leak which is why I pulled my headers off..

I have no more ideas left as to what can be causing a lean code to be thrown.. Remember, the lean code will get thrown with the car just sitting there at idle and does so once the car goes to open loop.. It doesn't take any serious engine load to get the lean code.. Any help/suggestions are greatly appreciated.. I don't know what else to do, and the shops that Ive talked to are out of ideas..

Thanks..

 

first-when the car is cold it runs in open loop.2nd-02's unplugged simulates a open loop run.
look for a air/vacuum leak on the right bank[bank 1 is cylinders 1-3-5-7,bank 2 is the left,2-4-6-8],bank 2 would set po174.i would check for vacuum/air leaks on bank 1[right side],make sure none of the secondary air check valves are sticking open,check fuel pressure,etc.
if you are getting po171,this is a lean fault for bank 1[passengers side]

 

Thanks for the clarification.. Fixed..

Wait... Your saying bank 1 is the passenger side? Ive been reading that bank 1 is the drivers side.. How sure of this are you?

 

this happened to me on my 04 Z also. when i took it in to the dealership they hooked up the front O2s wrong. the left O2 should be hooked into the right harness and the right O2 should be hooked into the left harness. when i pulled my plugs they looked exactally how you described. hope this helps.

 

Well, I have LG headers, and according to Lou.. The 02 sensor from the left collector goes to the left side of the car. And the 02 sensor fromt he right collector goes to the right of the car. Exactly the way the car is wired..

I do appreciate the help though as that is a common problem with a header install..

 

i'm retarded,you are correct,the left bank is 1-3-5-7,right bank is 2-4-6-8.

 

PCM was doing what was reported to it so if the crummy welds caused the left O2 to report lean by sucking in air then of course PCM would be adding excess fuel to that side.
Depends on where the leak is, if before the O2 or close to it then the O2 would report incorrect lean condition
You shoud be using a PCM scanner and seeing what the O2s tests report and what O2s themselves are reporting.