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p0171

then i have freeze frame data on the specs of my car when the cel came on


fuel sys1 cl
fuel sys2 na
calc load 13.33%
ect 81(celcius)
stft 25.78%
ltft 29.69%
map 39.00 kpa
eng rpm 1990
speed 85kmph
spark advance 34.00
iat 2 (celcius)
maf 8.22g/s
tps 28.28
o2s bank 1 sensor 1 .85
stft bank1 sensor 1 25.78%
o2s bank 1 sensor 2 .13
stft bank 1 sensor 2 99.22%

 

milage......and have you had any work done latly....

 

brand new maf, and o2 sensor 2 days ago. new plugs at 70k current mileage is at 75k

 

I'm going with the o2

 

well after replacing 5 and the BRAND NEW ONE still reads the engine is lean, i'd say thats not the cause. look at my diagnostic freeze frame, one o2 reads .8 and the other is .1, one is rich as all and one is super lean...there not too far appart wonder why it'd be like that?

 

Vaccume/ Intake leak? Unmeasured air getting in, throwing your LTFTs high,
LTFT higher then 20, yours are 29, will trigger a P0171 LTFT = Long Term Fuel Trim...

As air comes in, it's measured, by the maf
Then a calculated ammount of fuel is added, by the injector pulse
Then the exhaust is monitered by the O2 Sensors,
If your too lean or rich it will adjust the pulse width accordingly, (Thats was CL means, for Closed Loop Fuel system) The more fuel needed to bring you to 14.7, the higher your fuel trim goes. 0 = perfect >20 = P0171 <-20 = P0172 There is more to it then that, but I believe my simplified information is accurate for the most part. Somehow something happened, and your getting more air then your PCM knows about, (An Intake leak/vacume leak, falty maf sensor) or your getting incorrect information for feedback from the O2 sensor (O2 sensor/wire malfunction)

 

Id say your super lean one is bad....
Cuaseing your PCM to throw/add more fuel
Runnign your trims up
Triggering P0171

Youd think thered be a code for a O2 sensor disagree

 

ever replaced your cat?

 

meow...

 

stock cat, but regardless, this wouldnt be the root of the problem just be a symptom. how many vaccum lines are there? i swear i hear a hissing sound on the right rear side of the engine

 

Wasn't there an updated engine calibration for this issue . I remember having the dealer flash mine on my 06 SS/SC for this very reason. I believe the Calibration was for 05-06's only .... 07's weren't included in the TSB.

EDIT: Found it


#06-06-04-033: 2.0L/2.2L LSJ/L61 Engine Malfunction Indicator Lamp (MIL)/Service Engine Soon (SES) Lamp Illuminated with DTC P0171, Fuel Trim System Lean, Set (Reprogram ECM) - (Jun 21, 2006)


Subject: L61 Engine Malfunction Indicator Lamp (MIL)/Service Engine Soon (SES) Lamp Illuminated with DTC P0171 "Fuel Trim System Lean" Set (Reprogram ECM)


Models: 2005-2006 Chevrolet Cobalt, Cobalt SS Supercharged

2006 Chevrolet HHR

2004-2006 Chevrolet Malibu

2005-2006 Pontiac Pursuit (Canada Only)

2004-2005 Saturn ION Redline

2005-2006 Saturn ION

with Ecotec™ 2.0L or 2.2L I-4 Engine (VINs P, F - RPOs LSJ, L61)




--------------------------------------------------------------------------------
Condition
Some customer may comment that the MIL/SES lamp is Illuminated. Further diagnostic investigation with a scan tool may reveal a DTC P0171 Fuel Trim System Lean. No other driveability or performance concerns may be reported.

Cause
The most likely cause of this issue may be that the engine calibrations need to be updated to correct a variation in the Mass Air Flow Sensor.

Correction
DO NOT replace the MAF sensor, the ECM or any other parts.

 

spray flamable fluid carefully and away from spark plugs/coils just in case....use starting fluid for diesels that comes in aerosol cans...helps me find vacuum leaks very fast

 

cracked intake mani? had a guy that lives by me have this code and changed his o2 sensors like 4 or 5 times....finally took it in and that was the problem

 

Sub for answer

 

I had this same issue...I had also found the tsb...had the ecu reflashed with the updated tune...never came back...

 

Ok .. ii had been noticing a hissing sound but then code p0171 started popping up... I deleted it..came back 2 weeks later...I deleted it again..came back a week later... Deleted it and came back yesterday... And now it comes back on every time I delete it after a few mins of driving... I believ its a vaccum leak somewhere.. but how do I test it??