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04 Forester XT
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25 Posts
Discussion Starter #1
How often do these go out? Is it unsafe to run your car "lean"? Also, if this is my problem, is it common to smell oil burning in the first 15 minutes of running the car?
 

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2007 Forester Sports XT 4EAT
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In my experience, the O2 sensor can be failing a long time before it drops a CEL code. Normally when the front O2 sensor (Air/Fuel sensor) is starting to fail, it causes a overly rich condition. Do you have a CEL, if so, what's the code? :confused:

As to burning oil when started (first 15 min) being normal. Not normal on my '03 or '07. They tend to run a bit rich when they're first started. :smile:

Bobby...

'07 FSXT MODding Journal
'03 X MODding Journal
 

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04 Forester XT
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25 Posts
Discussion Starter #3
code was P0171. They then said "May need FT O/2 sensor and Air flow meter.

The last time I took it in there they informed me that my car was leaking a little oil (which it never had been)--so maybe it's dripping onto something hot and burning off? Oil level hasn't been dropping as I check at every fill up. I feel like they do little sabotages everytime it goes to the dealer maintenence dept.
 

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Registered
04 Forester XT
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25 Posts
Discussion Starter #4
In my experience, the O2 sensor can be failing a long time before it drops a CEL code. Normally when the front O2 sensor (Air/Fuel sensor) is starting to fail, it causes a overly rich condition. Do you have a CEL, if so, what's the code? :confused:

As to burning oil when started (first 15 min) being normal. Not normal on my '03 or '07. They tend to run a bit rich when they're first started. :smile:

Bobby...
is the burning oil smell an "overly rich condition"?
 

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Super Moderator
2007 Forester Sports XT 4EAT
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is the burning oil smell an "overly rich condition"?
Overly rich (to me) smells like fuel, totally different from oil. Of course that's using my "nose". :wink:

You may have a oil leak or seepage that builds up & drips on something that gets hot. You might want to look around under your Forester. If you have the plastic undertray, you'll need to pull it off so you can get a better look. :wink:

Bobby...

'07 FSXT MODding Journal
'03 X MODding Journal
 

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Super Moderator
2007 Forester Sports XT 4EAT
Joined
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35,949 Posts
P0171 - Fuel trim malfunction (A/F too lean). You might try cleaning your MAF sensor. It might be dirty, causing an incorrect signal to the ECM. :confused: Just a guess of course. :wink:

Bobby...

'07 FSXT MODding Journal
'03 X MODding Journal
 

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Super Moderator
2007 Forester Sports XT 4EAT
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35,949 Posts
Got any hints to clean the MAF sensor? I don't even know where it is.
The main thing is not to poke or probe inside the air channels. I'm getting tuned in a couple weeks & my tuner advised this to clean the MAF.

Using specific MAF cleaner (CRC makes some) or isopropyl alcohol (rubbing alcohol). If you use a non-aerosol liquid, just pour some into a clean zip-lock, seal the sensor in and shake the bag by gripping the sensor housing. You'll probably be quite surprised at the gunk that ends up in the bottom of the bag! If it's aerosol, just spray (gently!) away inside and out.

In addition to the above, I used compressed air (in a can, used for dusting) to dry off all the liquid. Again, don't poke or probe any of the air passages. :wink:

Bobby...

'07 FSXT MODding Journal
'03 X MODding Journal
 
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