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Old 05-14-2010, 04:28 PM   #1
Scooby Specialist
Member#: 212509
Join Date: May 2009
Chapter/Region: NWIC
Location: marysville,WA
unde your hood makin
your **** go faster

Default p0171 cell wont go away.

07 forester xt 2.5 turbo 5sp 48k
3" cat back exhaust
ebay cai
50/50 blow off valve
all parts have been on car 9 months no problems

ok little run down.
last sat engine light comes on. P2097 post cat too rich
dealer diagnoses at bad maf sensor and cai causing car to run too rich.
ok. so i go home pull cai out and shorten so filter is in engine bay. clean pipes and maf. go drive light comes back on. so i just ordered a new maf without checking code again.
put new maf and go to check code and clear it and its a diff code now its p0171 bank 1 too lean. clear it with new maf sensor installed hoping it will fix issue

code comes back. after more research and talk with my father whos a service manager he has me diagnose the rear o2 sensor. it checks out fine. car has 48k runs fine excpet kinda rough idle. so i replace the fuel filter. and install my walbro pump while im there. go get gas and on second drive cycle in of about 5 miles light comes back on same code.

im lost. only thing i could think of is its the front o2 sensor..
i double checked all intake connections for leaks. nothing. should i put the intake back to cai or put stock box on.

heres what the scanner says


fuel system closed loop
calculated load 23.5%
engine coolant temp 190*
STFT bank 1 24.2%
lift bank 1 14.8%
intake manifold pressure 14.7 in.hg
engine rpm 2735
vehicle speed 34 mph
ignition timing 52.5*
intake air temp 93*
mass air flow sensor 2.29 lb/min
throttle position sensor 20.3%
secondary air status off

i have been doing tons of research on this and have done everything that people have had to do to fix the problem. except put stock intake back on which i dont have..
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Old 05-14-2010, 06:08 PM   #2
Scooby Specialist
Member#: 212509
Join Date: May 2009
Chapter/Region: NWIC
Location: marysville,WA
unde your hood makin
your **** go faster


well im gonna go out and make it known that i ****ed up lol..
so ever since i came home from the dealer and cleaned my maf and shortend my intake its never been the same code its always been too lean.. first code was too rich
well when i shortened my intake the tube was kinda a pain to make fit with the filter in the engine bay and i had to push the filter over the tube a little extra..
well after all my struggles i decided to put it back to cai style and when i got all the piping back on and went to grab the filter it dawned on me.. the filter is a cone filter with the reverse inside cone from the front and when i made it a short ram i had to push the filter farther onto the tube.. basically it was like putting a cone restrictor in my intake pipe lol.. so its all good...
probly never even needed a new maf or fuel filter but whatever at least my suby is all better..
lesson learned do one thing at a time when trouble shooting to narrow your problem.. process of elimination:discomonkey:
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