P0171: System too Lean (Bank 1) need help
09-19-2010, 05:55 PM
#1
P0171: System too Lean (Bank 1) need help My car keeps throwing this code. I have checked every place for vacume leaks. The car runs fine. Could I have a bad 02. Car has Slp long tubes and no rear 02s. Back in January I took off my Flowmaster cat back and replaced it with a Magnaflow. I was thinking I should swap the drives side 02 with the passenger side 02 and see if the problem goes to bank 2. Can I get some input from you experts.
09-20-2010, 12:36 PM
#2
Sounds like a good plan. Just make sure you use anti-size compound on the threads when you switch them.
If you sensors are sensing too much O2 (too lean) then they are probably working correctly. You may have a fuel delivery issue on that side of the engine. Injector, etc.
If you sensors are sensing too much O2 (too lean) then they are probably working correctly. You may have a fuel delivery issue on that side of the engine. Injector, etc.
09-23-2010, 12:31 PM
#6
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You need to look at O2 data for bank 1. At idle it should at times go over 800 mv and under 200 mv. If it doesn't go over 800mv try to force it by driving WOT. Because there is no bank 2 code (P0174) I would assume you will see bank 2 go over 800 mv. If it does not go over 800 mv at WOT and bank 2 does it is most likely an O2 sensor. If it does go over 800 mv when loaded but not at idle it probably has a vacuum leak.
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10-15-2010, 02:26 PM
#9
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Have you changed your fuel filter? That could be clogged and be causing fuel starvation, but since it's only on one bank, I'm not sure that would be an issue. Hopefully that would help!
10-26-2010, 10:24 AM
#12
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I've had filters almost completely clogged to where I could barely blow threw them after 25k miles; on my truck. I change them sooner than that on my car.
10-26-2010, 07:09 PM
#13
Well I changed out the filter I had a date on it of 7-2007 so it has been on there 3 years but probably only 5000 miles. Car is not a daily driver. I drove down to the beer stor and back probably 10 miles total and the ses light did not come on but with my OB2 scanner plugged in it showed the code on and off a few times. Not sure what else to try maybe the injectors or fuel rail. This car does have a nitrous set up on it but I dont see how that would change anything. I have not sprayed at all this year. My k&n filter is somewhat dirty I think I am going to get rid of it and go back to paper filter. Any one else have any good ideas?
11-01-2010, 04:29 PM
#14
Well changing out the fuel filter was not the fix. I guess I will pull out the injectors and inspect and clean them. I need 02 sensors for my other car I am building so I was going to get some Bosch 13111s I could try putting those in there to see what happens but I dont think that is the fix. Does anyone have any other ideas?
11-04-2010, 01:15 PM
#18
Might have something to add here... I recently bought my Trans Am and started to get "Too Lean bank 1 and bank 2" The throttle body has been ported & polished, and the MAF has no screen.
We replaced the MAF with a stock Delphi 85mm (with screen). It's been 2 days, and I have driven the car in the same manner to see if the code would come up, but it hasn't. I'll check in if the code comes back. Do you have a screen on your MAF? If not, it might be affecting the airflow around the sensors, causing them to read incorrectly.
We replaced the MAF with a stock Delphi 85mm (with screen). It's been 2 days, and I have driven the car in the same manner to see if the code would come up, but it hasn't. I'll check in if the code comes back. Do you have a screen on your MAF? If not, it might be affecting the airflow around the sensors, causing them to read incorrectly.
