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System too lean code after x pipe install.

6.8K views 10 replies 7 participants last post by  FlMuPhi198  
#1 ·
P0174 system too lean bank 2 is what I keep getting after I installed my x pipe and it is really confusing me. Could this be an exhaust leak? What could it possibly be? I really don't have too much time to work on it tomorrow!
 
#2 ·
There is nothing in your garage. You put on an x-pipe. Catted x-pipe? Off-road x-pipe. Long-tube headers with an off-road shorty x-pipe? More information is needed.
 
#5 ·
The driver side (bank 2) doesnt use a gasket. Just the passenger side (bank 1) I had that code pop up when one of my O2 sensor wires were ripped. So check for that. Make sure all the O2 wires are good, and before you screw the O2 sensor into the X pipe, twist it the other way, then when you go to screw it in, all the wires arent all tangled up.
 
#7 ·
So is it catted then or off road. I just put my off road magnaflow on mine and I keep getti g a check engine light as well for having no cats but I use my tuner to turn it off over and over but I'm looking to sell it. What brand of x pipe is yours.
 
#8 ·
So I just got out from under there and I think that the pipe's fitment is horrible. I unbolted everything and it still was not mating to the drivers side header correctly. I am really thinking of calling it quits and having a shop try their hand. I have never had a shop do anything but an alignment on it before. If somebody wants over 30 bucks to fix it I am throwing the stock on back on and selling this thing.
 
#10 ·
You're going to have to man up and get a 1/2" breaker bar to tighten the nuts to get a good seal - if you're smart you'll put some antisieze on the studs first, and use new nuts.

You have to crush steel with two nuts over a dome to get a good seal, and crush them pretty good. When you think you've got everything bolted up and sealed up, leave the car in the air and fire it up. Move your hand around all the joints and flanges to feel for the exhaust coming out. If it's moving out, turn it off and get back under the car and tighten it up some more.


No, it isn't easy, and no, you won't be able to apply enough torque with a 3/8" ratchet. My 3/8" impact wrench didn't have the ass to tighten it properly, and I didn't want to risk snapping off the stud with my 1/2" impact.

Take your time, tighten slowly and smoothly, alternating between which nuts you're tightening to uniformly crush the steel on the X pipe to the dome on the exhaust manifold.



P0174 is for the driver's side. This can be caused by an exhaust leak or a damaged upstream O2 sensor. My money is on an exhaust leak at the manifold/x pipe connection.
 
#9 ·
when i installed my bbk o/r x-pipe i ran into the same problem. for me the fitment issues were because of the spacers on the stock manifold studs not allowing the the flanges to meet. By removing the stock studs and spacers replace them with bolts you allow the flange to meet properly getting rid of your exhaust leak. as for your CEL it depends, it could be because of the leak you have or lack there of catalytic converters :D