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Discussion Starter · #1 ·
Hey Guys,

I'm new to Subaru family, I just picked up a 2002 WRX (5-speed) it is running extremely lean. Does anyone have a cobb tube for a STI cold-air intake and after market cat-back exhaust. I called cobb and they only have a tune for their SF intake and aftermarket exhaust. I live in the middle of no-where and would like to avoid driving 3 hours to just get a tune. I would like to start driving the car but it is running to lean right now, please help!

Chris
 

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How is it tuned now? Do you have any logs of the afr?

Your best bet may be to investigate a twctrix cable and open source tune via an e tuner

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Ditch the intake and flash it back to a safer Stage 1 OTS map

Then check for the dozens of vaccum leaks its going to have

Replace fuel pump
Replace fuel filter
Fix any other leaks

Then seek out an actual tuner
 

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Discussion Starter · #4 ·
Hey guys. It's just tuned stock right now I purchased the car with the CAI. There is no one near me that can tune these cars. I'm in moline IL closet place I've found is 3 hours. Does anyone have a stock exhaust they are willing to part with?
 

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cobraking00 said:
Hey guys. It's just tuned stock right now I purchased the car with the CAI. There is no one near me that can tune these cars. I'm in moline IL closet place I've found is 3 hours. Does anyone have a stock exhaust they are willing to part with?
SPT intake
Catback exhaust

Neither of these should cause the vehicle to run lean. Subaru produced their intake to be installed and retain the factory warranty. A catback exhaust doesn't adjust airflow enough to throw off fueling.

You have a mechanical issue you need to address, not an aftermarket parts issue.

That said, don't be afraid to drive the vehicle 3 hours for a good tune. P&L outside of Chicago brings in JR to do ECU calibrations, and he's a member of the "elite".
 

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Discussion Starter · #6 ·
Ej257. I would agree that a catback would not change the a/f ratio, but a CAI that uses a different MAF body would. The 02s are strictly a MAF based car and because this has a aftermarket CAI which uses the stock MAF sensor but changes the body that it is housed in it so it flows more air. Typically on newer cars that's not a problem because they are equipped with o2 sensors which monitor the a/f coming out and will tell the computer to correct it if it's incorrect. I would love to go up to P&L but I can't afford to take a day off of work to go up there. They are closed on Saturday.
 

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cobraking00 said:
Ej257. I would agree that a catback would not change the a/f ratio, but a CAI that uses a different MAF body would. The 02s are strictly a MAF based car and because this has a aftermarket CAI which uses the stock MAF sensor but changes the body that it is housed in it so it flows more air. Typically on newer cars that's not a problem because they are equipped with o2 sensors which monitor the a/f coming out and will tell the computer to correct it if it's incorrect. I would love to go up to P&L but I can't afford to take a day off of work to go up there. They are closed on Saturday.
I'm quite familiar with MAF-based fueling, as well as the AFR corrections that your '02 WRX applies.

How are you determining that your vehicle is "running lean"?

I'll restate my original comment, that if you have the Subaru intake and an aftermarket catback and you're experiencing a "lean" condition, your issue is most likely with something besides the aftermarket parts.
 

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Discussion Starter · #8 ·
Ej257. I don't have a stock intake. It's a aftermarket CAI. After Putting the car on the data logger the alarm ? code given is a lean condition code and using a sniffer I can see the car is running lean. Everything else on the car is working correctly. The only other problem it could be is the MAF itself. Thanks for your input.
 

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It could be vacuum leaks.

You said before you have an sti intake. What intake do you have?

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cobraking00 said:
Ej257. I don't have a stock intake. It's a aftermarket CAI.
From your original post:
cobraking00 said:
Does anyone have a cobb tube for a STI cold-air intake and after market cat-back exhaust.
Does your intake look like this:


There is no "STI" brand intake that I've heard of for your car; SPT is sometimes confused.

cobraking00 said:
After Putting the car on the data logger the alarm ? code given is a lean condition code and using a sniffer I can see the car is running lean. Everything else on the car is working correctly. The only other problem it could be is the MAF itself. Thanks for your input.
What is the code (P####)? P0171?

A pre-turbo intake leak (e.g., torn inlet tube)
A vacuum leak
Dirty MAF (when cleaning, make sure you clean the MAF, not just the IAT sensor)
Dirty IACV
Front O2 sensor
Injector issue

All things that can cause issues you're talking about.
 

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Discussion Starter · #11 ·
EJ257 Yes it does look like that sorry for the confusion. I will put the car back on the data logger and get the exact code and let you know. Thanks for all the help.
 

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cobraking00 said:
EJ257 Yes it does look like that sorry for the confusion. I will put the car back on the data logger and get the exact code and let you know. Thanks for all the help.
No problem on the confusion. The "Subaru intake" I kept referring to was the SPT one pictured...

With that confirmation, I stand by my previous statements in which you likely have a mechanical issue besides the intake that is causing your DTC.

Review the following to make sure that's not the cause of your issue:
EJ257 said:
A pre-turbo intake leak (e.g., torn inlet tube)
A vacuum leak
Dirty MAF (when cleaning, make sure you clean the MAF, not just the IAT sensor)
Dirty IACV
Front O2 sensor
Injector issue
#1/2 can be checked with a pressure test
#3/4 are "routine maintenance" items that should be taken care of but are sometimes missed
#5 can be tricky because the sensor can look "alright" but in fact be bad; the front O2 sensor is what is responsible for applying AFR corrections
#6 is the least likely, but if you do a full Seafoam treatment (top-end, injectors, oil system) on the vehicle, it probably wouldn't be a bad thing
 

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Discussion Starter · #13 ·
EJ257, so I got the car to finally idle and run right under light loads, however when i put the car under a decent load or go WOT it still wants to run really lean, we are talking 21.22 AF ratio. I've been going through the car and can't seem to find any vacuum leaks. Any thoughts now?
 

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Discussion Starter · #14 ·
DATA LOGGING RESULTS

Hey guys I want to post my data logging results and when I try to attach a file the messenger just says invalid file name. How can I fix this
 

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Can you upload it to google docs

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Get one, they are free and throw away.

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Discussion Starter · #18 ·
XJ roger that will do. In the mean time i just did a full smoke leak down test and the results were no vacuum leaks at all. Not sure where to turn next. Looking at possible MAF gone bad and upstream o2 sensor. After that all I can think of is the fuel system, either the fuel pump is wore out, injectors are worn out, or there is a hole in the line coming off the fuel pump causing it to loose pressure.
 

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XJ roger that will do. In the mean time i just did a full smoke leak down test and the results were no vacuum leaks at all. Not sure where to turn next. Looking at possible MAF gone bad and upstream o2 sensor. After that all I can think of is the fuel system, either the fuel pump is wore out, injectors are worn out, or there is a hole in the line coming off the fuel pump causing it to loose pressure.
I would clean the MAF to start. Oiled cotton filters tend to foul them.

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