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Discussion Starter · #1 · (Edited)
check engine light and MIL QUESTION

I am going t install a cobbs turbo back and aps cold air intake and found out that i may get a check engine light, knowing i can get the MIL i just have ?'s about it, does the MIL just fool the ecu by sending a signal that it want to see. If so i guess the real question is does the ecu try to adjust by reading the rear o2 sencer, if so is there a better way to correct rather than tricknig the ecu, I am a newbie and love my car, just want to do it right any input will help me understand, thank you:rolleyes:
 

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Probably. I installed a TurboXS turboback + uppipe recently, and just got my first P0420 (cat inefficiency) code yesterday. Going to install the MIL Eliminator this weekend, should keep that from recurring hopefully. Don't know how the Cobb turboback is set up, if they moved the O2 sensor behind the cat like the TurboXS and you didn't do the uppipe too, you might not get the code.

PS: a *lot* of people recommend against CAI systems, just fyi.
 

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Discussion Starter · #4 ·
No I did not install the uppipe yet, but all i have now is a hi flo cat in the down pipe and 02 is basicly in the same spot, also yes i have been reading that i should get a short ram intake rather than a cai, think i will order the MIL AND INTAKE THIS WEEKEND TOO.. the reason i ask the ? is i bought this off a friend and he said when he first installed, he got the cel. and he had a little bit of blue smoke come of his exhaust at times, and i didnt know if the ecu was tring to adjust, could this be bad if mil is not installed

thanks wrx420 its about that time :)-~
 

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The cel is mostly an exhaust 02 sensor fault. It happens as soon as you mess with your ecu. Disconnect the nes terminal for a minute and it will give you some time b4 it comes back on. It's gonna keep happening until you flash your computer.
 

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He meant negative terminal, typo no doubt. The Cobb reflash will remove the code, though I think you have to request them to enable that feature. If you still have a cat in the dp and you have your stock up, you might actually avoid CELs though (or not).
 

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I have a 02, with lots of toys including a up pipe, down pipe with a 3" back exhaust. I put in the mil and I still get the engine light.
 

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boostfreak said:
The cel is mostly an exhaust 02 sensor fault. It happens as soon as you mess with your ecu. Disconnect the nes terminal for a minute and it will give you some time b4 it comes back on. It's gonna keep happening until you flash your computer.
i've never heard of a reflash or new EMS eliminating the CEL.

the MIL eliminator sends a constant voltage signal to the ECU, telling it that the emissions equipment is functional. the rear 02 sensr (the one the MIL Elim intercepts) is only used for emissions. the front 02 sensor is the one used for A/F and other ECU analysis.

the white smoke your friend saw was most likely the residue on his new exhaust from the manufacturing process.

dR
 

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dark_rex said:
i've never heard of a reflash or new EMS eliminating the CEL.
:confused: I've read a number of people talking about asking Cobb to disable the P0420 code from their AccessECU flashes, for example.
 

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Discussion Starter · #13 ·
ok few more ?'s,

where do i find the front 02 sencer

also the egt in the uppipe, this mod, is this like the mil, and tells the ecu what it want to see, or does it adjust from it, inother words why do you get a cel from the egt:confused:
 

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wrx420 said:
He meant negative terminal, typo no doubt. The Cobb reflash will remove the code, though I think you have to request them to enable that feature. If you still have a cat in the dp and you have your stock up, you might actually avoid CELs though (or not).
Sorry about the typo, it's neg terminal. And the "he" is a "she":rolleyes:
 

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hughy said:
ok few more ?'s,

where do i find the front 02 sencer

also the egt in the uppipe, this mod, is this like the mil, and tells the ecu what it want to see, or does it adjust from it, inother words why do you get a cel from the egt:confused:
the front o2s is in the right hand (passenger's side) exhaust manifold collector pipe.

the EGT mod replaces the variable resistance of the EGT sensor with a fixed resistance. 2k2 is generally used (that is, 2.2 kilohms), though i used 3k0 to make it a little bit "colder" in reading. the EGT sensor is a thermistor, which lowers its resistance as it gets hotter.

some have postulated that the sensor may not be able to take the prolonged direct flow of gasses that now flow through the unrestricted up pipe. or it might just get inputs that are out of the allowable range. either way, it nets a CEL.

hth
ken
 

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Re: check engine light and MIL QUESTION

hughy said:
I am going t install a cobbs turbo back and aps cold air intake
Since when does Cobb sell a Turboback? Last I checked a catback was all you could get from them...:confused:

http://cobbtuning.com/wrx/
 

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Discussion Starter · #17 ·
yes. your right, I believe that is still all you can buy thru them, but a guy i know that has a shop called hids4less.com where i got my hids from, also my front and rear morretts, cobbs gave them a turbo back set up with aps intake and unichip, but he just bought the STi and i bought his system. which i installed this weekend and went well, i also installed the mil, and i did get rid of my po420 code great, but i still have a po447 gas cap code, whitch will not reset, dealer issue
 

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Oh, gotcha...
 
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