I have installed an LQ4 all stock inclulding headers into my truck. The left bank is lean according to the error codes. I have installed a new o2 sensor on that side after the header and have removed the rear sensor that is behind the cat. I used an after market harnes from current performance and had the sensor removed from the programming.

Is it possible that my new o2 sensor is just bad or wired wrong? or are there other things that I should be looking at that could cause the left bank to run lean? I have had some tell me to check the spark plugs but I am thinking that if I wasn't getting spark I would be running rich. Am I thinking right? what else should I be looking at?

Many thanks!

 

Leaky intake gasket, leaky exhaust manifold gasket. How does it run?

 

It seems to run well. I would not have known that I had a lean bank unless there was a trouble code.

 

i am sure you know, but what side are you calling the left?

 

I am assuming (as I have been told) that the left bank is the passanger side. I just get the left bank lean trouble code. I have been running the engine on 87 octane and am thinking that even if my new tune required 91 if the problem was octane wouldn't both banks be lean?

 

someone que in if i am wrong, but i thought for sure that banks were determined as seen from the driver's SEAT. Therefore, the left bank would be on the drivers side.

 

A scan tool refers to bank 1 as the drive's side and bank 2 as the pssenger side. Typically bank 2 runs leaner by a couple of percent and it may be just lean enough that it sets the DTC. Usually fuel trims in the double digit ( plus or minus 10 ) and greater will set a code. I'm sure their's a few exceptions, but this is usually what I see. Log with a scan tool and look for the reason the code is being set.

Good luck,

Richard

 

in order to set the cel the PCM needs to see +/- 25% LTFT. +/- 24% or lower only indicates the PCM still has control over the fueling. I consider up to +/- 5% acceptable when tuning.

 

Brian,

Could you translate that last one so someone that was dumb, such as myself could understand it?

In light of the fact that the left bank runs leaner, would it be worthwhile to put premium in it and see if the error code does away? I don't know for sure but my tune might be for 91 octane. Does this make sense at all?

Thanks,

 

All I have is JBA Headers and flowmaster catbacks, and my code was left bank too lean too...i cleared it 3weeks ago and it hasnt coem back yet?