kirtondog23

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!

67rsss

iTrader: (4)

Where are you buying gas (what state), how much alcohol is in it, and what market was the computer programmed for? We found that with the high alcohol content in the gas in MN, the 02 Suburban (originally CA vehicle) is very picky about where we buy gas. If the Alcohol goes above 10%, we start throwing lean codes on both banks. May not be your problem, but something to consider...

bczee

iTrader: (12)

check the following...

check the plugs to see if they are lean, try switching O2 sensor from the other side or use one that you deleted.

check for vacuum leak on that side.

Dyno paul

WE had an issue the same as yours On a Dyno Engine and the left bank oxygen sensor wiring was switched with the right. The computor is always trying to correct the wrong bank.

shifty`

iTrader: (3)

there are a couple of OBDII error codes to indicate lean bank, also - knowing the generic OBDII 'p-code' you actually threw would probably help someone here diagnose your problem a little better - the exact error is typically useful to determine where to look first. 'lean' condition usually indicates that you have more air than fuel - so, rule out vacuum leaks, rule out the possibility that your injectors aren't underspraying, rule out the previous comment re: O² sensors being backwards. If you've removed or replaced your intake at any point during your swap, you might want to take it off, check the rubber gaskets to make sure all are there, and make sure you torque it back down in proper order and to spec.

on the VR6 in my VW, the past couple of weeks i kept getting a CEL and it was indicating lean on my left bank, and it wound up that either my MAF was screwed up, or I had a vacuum leak b/c my brake vacuum hose was cracked on both ends. not sure which - i found that the steam line from my donor LS1 trimmed to fit perfectly for my VR6 brake vacuum line and i took the MAF out and used CRC MAF cleaner on it - been running all week with no new codes showing up.

shifty`

iTrader: (3)

Oh - and this might sounds stupid, but I've heard of guys on here who couldn't fire up....and it wound up their injectors were clogged....they just tapped on them a few times and fired right up (I've heard this more than once). makes me wonder - have you tapped on your injectors?

kirtondog23

OK sorry for the massive delay, I finally have the thing shifting right. (TCC wire in the wrong place.)

The exact code is P0174 fuel system too lean bank 2. we tried clearing the code and it resets almost immediately, (engine at idle, temp at 87).

Any suggestions?

Thanks

Sabre002

iTrader: (7)

how would you trace this out do you have the pin outs for the O2's?

kirtondog23

Also I noticed while driving the car yesterday and today that the exhaust from the cat back gets really hot, I mean really hot, to where the floorboards can almost burn you and the paint has bubbled in places.

I am guessing that it really is that the o2 sensor is bad and that the engine is running rich since the o2 sensor is not sending the right signal back to the computer and the extra fuel is heating up my exhaust since it is not getting burned in the cat.

Does this make any sense?

Also does anyone know how to test the sensor to see if it is working? I have an Ohmeter but do not know what range I should be in or which wires I should be checking.

kirtondog23

I have used the ohmeter and I get a reading of 05 on each side both right and left side. Should they read the same?

Any other ideas?

THanks

jeepinpete

If you have an exhaust leak, air can be sucked into the exhaust. If this happen ahead of the O2 sensor, it will pick it up, and read lean (there is extra oxygen in the exhaust). It has no idea that there is air getting into the exhaust. It will richen the mixture trying to compensate for the extra O2.

Different ECM/PCMs react in different ways. I had a Fiero that had a crack in the exhaust manifold. It would run very rich to try to compensate, then I guess it would reach its internal limits, set a code, and ignore the O2 sensor. It would run very good of awhile, then try to use the O2 sensor again. It would keep doing this until I unplugged the O2 sensor.

Testing the O2 sensor with an ohm meter is nearly impossible. Swap the sensors from side to side and see if the code follows the sensor. If not, you can be 99% sure that the sensors are working properly. If they are, you have some kind of exhaust leak, or a bad injector(s) that is running a cylinder(s) very lean.

kirtondog23

I have never removed an o2 sensor, do they need to be torqued to a specific tightness?

jeepinpete

I'm sure there is a torque spec on them, but they seal much like a spark plug, ie they use a crush washer. Just a good snugging should do the trick.

Sometimes they can be stubborn when removing them. If they don't want to come out, run the engine for awhile to warm up the exhaust. They will come out easier that way.

kirtondog23

cool thanks