As the title states, my car is throwing a P0171 bank 1 running lean... I just hooked up an OBD and used the torque pro app on my phone and tested the codes out of curiosity. I don't know if this is right or wrong, because I have not had an issues with the car recently. When I start it up it revs at 1500-2000 rpm depending on how cold it is and then slowly start to return to idle as the coolant rises, so I'm pretty sure this is normal. Any suggestions?
P0171 code, yet no symptoms...
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whatusername
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- 02 protege5
, ???? Lmao you wouldnt see anything leaking with an exhaust leak....... i have the same code ATm and my symptoms are poor fuel mileage and low idle 600 rpm and a slight surge on acceleration most noticeable in 2nd gear
So the intake hose is cracked, the place I went to has no parts in stock and they need to order one. I used electrical tape to cover it up for now. Regardless I don't think that resolved the issue... I checked for exhaust leak but I didn't find any sort of cracks or holes anywhere, there is a whistling noise coming from the exhaust manifold area, I don't know if that may be it, I have seen some youtube videos suggesting that as a possibility.
I used duct tape to fix the intake hose and it worked for a while. The problem is the filter is mounted on the chassis which causes the bellows to flex quite a bit especially if you have a manual trans. Any backyard repair job will quickly work its way loose. The only fix is a new hose or an aftermarket intake. For my P5 I got an Injen CAI on a forum for $60, for the sedan I bought the replacement bellows for less than $40 on Amazon.
You mention you have the Torque app. Get the real-time readings on the short- and long-term fuel trims. Positive means you're running lean, negative means rich. +/- 10% is about normal. If it hits over 20% and stays for a while that's when the light will trigger. You will see the readings change in real-time as you mess with the leaky intake bellows.
edit - If you wanna get fancy, set the datalogging up to record your STFT and LTFT and overlay it on the map. View your recording after a short run around the neighborhood. You will probably see fuel trims peg the lean side (positive) when you accelerate because that is when the bellows are stretched and leaking extra air past the MAF.
You mention you have the Torque app. Get the real-time readings on the short- and long-term fuel trims. Positive means you're running lean, negative means rich. +/- 10% is about normal. If it hits over 20% and stays for a while that's when the light will trigger. You will see the readings change in real-time as you mess with the leaky intake bellows.
edit - If you wanna get fancy, set the datalogging up to record your STFT and LTFT and overlay it on the map. View your recording after a short run around the neighborhood. You will probably see fuel trims peg the lean side (positive) when you accelerate because that is when the bellows are stretched and leaking extra air past the MAF.
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- 2010 Mazda5 GT
whatusername
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- 02 protege5
not to hijack this thread but mine came back today and i hooked my scanner up and got this... Fuel Sys1 CL Fuel Sys 2 NA Calc Load % 11.8 Ect (F) 187 STFT B1 25 LTFT B1 25 Eng Rpm 739 Vehicle speed 0 Mph.. can someone explain that & help me with this cuz i cannot seem to find a vacuum leak at all but have a good surging under hard acceleration especially in 2nd... i sprayed carb cleaner all over intake manifold and exhaust manifold and on all vac lines and it did not react.
This plus fuel trims pegged at 25% are typical signs of a torn intake bellow.
whatusername
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- 02 protege5