code P0171 - Bank 1 too lean...

[Bluextc]

I know it's a New Edge, but thought you guys might be able to help me...

The exhaust has been sounding like crap for about a week now. I noticed one tailpipe seems to be sitting lower than the other, so I thought maybe it was an exhaust leak, but today the service engine light came on, so I hooked up the sct and got "P0171 - System too lean 1". I did a quick look to see if anything was obviously wrong, but everything seems to be still connected properly and no obvious cracks in the hoses.
I haven't installed anything lately, the last thing was the h pipe, but that was about 6 or 7 months ago and it's been running fine until now. Here's the list of mods that I think might apply, in case that's needed:
Mac cai
accufab 75mm tb and plenum, mac o/r h pipe, flowmaster 40's, sct xcal 2 with 93 tune.
Thanks for any help you guys can give me...

 

[19mustang95]

did you shut off your rear O2 sensors with the xcal?

 

[Bluextc]

Yes, and it's been running fine since the h pipe install (about 6 months ago), this just started...

 

[19mustang95]

i'd guess it is your front O2s or something wrong with one of the EGR system's parts...do you have the EGR shutoff too?

 

[Bluextc]

honestly not sure, I am an idiot with the car, still learing, I have the sct tune in which turned of the sensors for the o/r h pipe, but I think something else is wrong, since it is only bank one reading an error... I've checked everything I know to check, but I'm sure I'm missing something, I made an apointment to take to car to my performace shop on June 4, but I'm afraid to drive it with the code being thrown out there until then, and I have to get to work somehow... I was hoping to figure something else to check out tomorrow before I have to drive it back to work on Wed. morning...

 

[19mustang95]

you'll be fine to drive with that code, i drove with that code for a couple months before it turned itself off...i never got a definitive answer on what caused it, but it isn't something that bad, its most likely something caused by the o/r H.

 

[Bluextc]

thank you! I originally thought that, but then I thought I must be wrong...

 

[jpajkos]

More then likely bank one isn't heating up properly which is pretty common these cars. I ran into the same problem with my car when I installed my long tubes. I found that my smog tube that runs from the back of the egr to my long tube was leaking which cause'd cold air to suck in there and the car would throw more fuel to try and fatn it up. It's nothing to really worry about. Usually something small.

 

[Bluextc]

Well, I started getting all stressed about it yesterday and called the shop I go to (I had an appt for next Monday) and asked them if they could look at it. They did, and it's a leak where my h-pipe meets the headers, he said it's nothing to worry about and bring it in on Monday like I was supposed to and he'll fix it (he didn't have the gasket he needed yesterday).

 

[CCM Power]

Read this and see if it helps you a little bit.






System Too Lean (Bank 1)

What does that mean?Basically this means that an oxygen sensor in bank 1 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1.

Note: This DTC is very similar to P0174, and in fact your vehicle may show both codes at the same time.

SymptomsYou will more than likely not notice any drivability problems, although there may be symptoms such as a lack of power, detonation (spark knock), and/or a hesitation/surge on acceleration.

CausesA code P0171 may mean that one or more of the following has happened:

The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters (K&N, etc.) can cause the MAF to become dirty if the filter is over-oiled
There could be a vacuum leak downstream of the MAF sensor.
Possible SolutionsPossible solutions include:

In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect all vacuum and PCV hoses, replace if necessary
Check for a dirty fuel filter and proper fuel pressure

 

[Bluextc]

Thanks! That was good info, but we did find the cause, it's an exhaust leak... getting fixed on Monday. I appreciate the help!

 

[CCM Power]

Great! Im glad you found the leak. This stuff can be such a pain in the butt. I just had to replace one of my converters because the old one had pieces floating around inside it. Sounded like marbles when I drove. Anything to give one a headache I guess. Im happy you found the problem! :thumb: