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Old 05-16-2008, 09:23 PM   #1
Obsessive
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Member#: 77302
Join Date: Dec 2004
Chapter/Region: MWSOC
Location: Billy Mays
Vehicle:
damn well better
bail me out of this ****

Default Infrequent RICH cycle during warmup... MAF?

I'm having what appears to be a very rich period after going Cobb Stage 2. This appears infrequently (only 2x so far), but is very weird and freaks me out when it occurs.

Upon starting the car, a very small amount of rich smelling smoke will come out of the tailpipe. If you rev the car up past 5000, this rich burn will get worse. This only has happened if the vehicle has been sitting for 30 minutes or so, and then is restarted (with the coolant warm, but not at full operating temp), and has happened BOTH times after an oil change (coincidence?).

I have done the following.

-Combustion gas test on the radiator (to check for head gasket leak). No coolant is being lost.
-Compression test. All cylinders within %7.
-Made sure oil was not overfilled.
-Pulled coilpacks and plugs. Cleaned coilpack connectors, plugs had no sign of contamination.


There is no CEL, and it doesn't run rough. When it does this, the engine done DOES change to a lower tone just like if you richen needles on a carb. It is a Stage 2, Automatic 2005 WRX running the 91 octane Cobb map. I run 5W-30 Valvoline dino-oil.

If you rev the engine, it will blow more uber-rich smoke. It is not white, its more bluish-grey, and as quickly as it starts, it stops. It does not smell sweet. I use 1/4QT between 5K oil changes. Turbo is clean and so is intercooler (inside).

So...

-PCV (havent checked this). Where the heck is it anyway?
-Warmup enrichment cycle issues with Cobb map, Stage 2, and the 4EAT?
-MAF needs to be cleaned? I have a Perrin filter and it's crazy-oiled from the factory. How do I clean the MAF?
-Leaky injector?
-Coilpack (I doubt this, as I would think it'd throw a CEL).
-Other?

Help is appreciated.

Eric
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Old 05-18-2008, 04:47 PM   #2
Engmus
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Location: South-East PA
Default

-PCV (havent checked this). Where the heck is it anyway?
-Warmup enrichment cycle issues with Cobb map, Stage 2, and the 4EAT?
-MAF needs to be cleaned? I have a Perrin filter and it's crazy-oiled from the factory. How do I clean the MAF?
-Leaky injector?
-Coilpack (I doubt this, as I would think it'd throw a CEL).
-Other?

- PCV Valve is a bit of a bitch, just did this on my 04 STi, its under the intercooler and the intercooler needs to be removed as thats the easiest way to get at it.

- Can't really comment on map issues, could be a tuning problem.

- Buy MAF cleaner (SPECIFICALLY), remove maf clean sensor, do not touch it with anything not even Q-tips.

- Maybe?

- Highly Doubt.

- Maybe do a upper engine decarb (Throttle body, BPV line) then replace plugs.
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Old 05-18-2008, 09:38 PM   #3
Obsessive
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Member#: 77302
Join Date: Dec 2004
Chapter/Region: MWSOC
Location: Billy Mays
Vehicle:
damn well better
bail me out of this ****

Default

Quote:
Originally Posted by Engmus View Post
-PCV (havent checked this). Where the heck is it anyway?
-Warmup enrichment cycle issues with Cobb map, Stage 2, and the 4EAT?
-MAF needs to be cleaned? I have a Perrin filter and it's crazy-oiled from the factory. How do I clean the MAF?
-Leaky injector?
-Coilpack (I doubt this, as I would think it'd throw a CEL).
-Other?

- PCV Valve is a bit of a bitch, just did this on my 04 STi, its under the intercooler and the intercooler needs to be removed as thats the easiest way to get at it.

- Can't really comment on map issues, could be a tuning problem.

- Buy MAF cleaner (SPECIFICALLY), remove maf clean sensor, do not touch it with anything not even Q-tips.

- Maybe?

- Highly Doubt.

- Maybe do a upper engine decarb (Throttle body, BPV line) then replace plugs.
Where can I purchase MAF cleaner?
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Old 05-19-2008, 07:45 PM   #4
Obsessive
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Member#: 77302
Join Date: Dec 2004
Chapter/Region: MWSOC
Location: Billy Mays
Vehicle:
damn well better
bail me out of this ****

Default

Nevermind...

CRC branded MAF Cleaner... Available pretty much everywhere. If not this, then 'electromotive' electrical parts cleaner.

Eric
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