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Old 05-26-2012, 09:32 AM   #1
ThorrinWRX
Scooby Newbie
 
Member#: 286814
Join Date: Jun 2011
Default Cold idle going very lean

Wondering of anyone can help me out. My car is going VERY lean when the car is cold. I have AEM A/F and it will drop off the chart and my car will almost die. Then it will catch itself and go to normal around 14.5 then back very lean. When the car is warm its perfect.
Mods are
DW 650 injectors
K&N typhoon intake
Invidia up and downpipe (catless)
Bigger TMIC
Catless Thermal exhaust

If I posted this in the wrong area I apologize.
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Old 05-26-2012, 09:43 AM   #2
Black94Snake
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Member#: 274499
Join Date: Feb 2011
Chapter/Region: NESIC
Location: RI
Vehicle:
2007 CGM VF'd WRX
12.70 @ 108.4mph

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wideband O2 sensors take time to warm up and read correctly. Try turning the key on for a minute (60 seconds) shutting it off and doing it again before starting the car.
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Old 05-27-2012, 07:38 AM   #3
b1aze
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Location: Marlborough, MA
Vehicle:
2010 Alpine 135i

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The problem here is the wbo2 isn't giving feedback to the ecu, it's a monitoring device and the car is reacting to, what is almost definitely, a leaned out idle. It's not a problem with the gauge, I'd look for leaks and maybe a retune if you dot find anything glaring.
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Old 05-27-2012, 07:49 AM   #4
Black94Snake
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Member#: 274499
Join Date: Feb 2011
Chapter/Region: NESIC
Location: RI
Vehicle:
2007 CGM VF'd WRX
12.70 @ 108.4mph

Default

Quote:
Originally Posted by b1aze View Post
The problem here is the wbo2 isn't giving feedback to the ecu, it's a monitoring device and the car is reacting to, what is almost definitely, a leaned out idle. It's not a problem with the gauge, I'd look for leaks and maybe a retune if you dot find anything glaring.
he is reading A/F shown on an external, stand alone device.


OP, watch what your front O2 sensor is doing, see if they are both running lean. You will likely find that its simply a case of the AEM WB just needs to warm up.
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Old 05-27-2012, 09:21 AM   #5
ThorrinWRX
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Default

It's not the gauge, the car was doing this before I got the wideband. I was explaining what the gauge was reading while the car is going nuts lol!. The car almost quits running because its going very lean, then ecu says woah way to lean let's dump some fuel and AF reads 13's then back lean again and the car almost dies. After the car is warm the idle is perfect.
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Old 05-27-2012, 09:58 AM   #6
Black94Snake
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Join Date: Feb 2011
Chapter/Region: NESIC
Location: RI
Vehicle:
2007 CGM VF'd WRX
12.70 @ 108.4mph

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and you are verifying this how? Do you have a datalog, or are you just assuming...
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Old 05-27-2012, 10:22 AM   #7
ThorrinWRX
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Going by the sound of the car and looking at my wideband. It's obvious something isn't right.
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Old 05-27-2012, 10:26 AM   #8
Black94Snake
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Join Date: Feb 2011
Chapter/Region: NESIC
Location: RI
Vehicle:
2007 CGM VF'd WRX
12.70 @ 108.4mph

Default

Quote:
Originally Posted by ThorrinWRX View Post
Going by the sound of the car and looking at my wideband. It's obvious something isn't right.
So, you are guessing. Did you ever stop to think that the cat warming process involves shoving pulses of pure air into the exhaust track to warm the catalyst up... for emissions purposes?
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Old 05-27-2012, 10:30 AM   #9
Black94Snake
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Member#: 274499
Join Date: Feb 2011
Chapter/Region: NESIC
Location: RI
Vehicle:
2007 CGM VF'd WRX
12.70 @ 108.4mph

Default




Quote:
Originally Posted by http://www.kstech.biz/servlet/the-10/air-pump-delete-block/Detail
Air pump is used only at start-up for a few minutes.
Quote:
Originally Posted by http://en.wikipedia.org/wiki/Secondary_air_injection
Secondary air injection (commonly known as air injection, or colloquially smog pump) is a vehicle emissions control strategy introduced in 1966, wherein fresh air is injected into the exhaust stream to allow for a fuller combustion of exhaust gases.
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Old 05-27-2012, 02:09 PM   #10
ThorrinWRX
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It's not always done this. It started after I upgraded injectors and grimmspeed ebs and tune.
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