EzekielOsiris

Hi everyone I'm new here. I have a Scion tc 07. I buy a header and catback exhaust system the brand is Speed Daddys also I buy a CAI with k&n filter all of this are from eBay. As soon I install this items the CEL came on. I did my research here and I read about some ppl fix it with spark plugs antifuler. I did as they said so I put two of them together and the 02 sensor it didn't work then I try with 3 Spark plugs antifuler it dint work eather. The last thing I have done I buy the Weapon-R 963-111-102 CEL Eliminator I installed already I disconnect the -cable from the battery to reset the computer. I drive for like 30miles but the CEL came back On. I went to Autozone to scan the CEL they told me that it can be either the O2 sensor or the CAI sensor. Like I said the CEL came on right after I installed all does items. I don't know what else to do.

bbsciontc

You need to find out the code and figure out what's causing the problem. Throwing parts aimlessly gets expensive, and clearly hasn't solved your issue. Have them tell you what code it's throwing, not just reset the light.

EzekielOsiris

I'm going to find out the code and what's causing it and I'll let you know as soon as I know.

xile6

Post the code number.
You could be chasing the wrong problem

EzekielOsiris

Ok I got the Code Number it's P0171

xile6

https://www.obd-codes.com/p0171

System to lean.
Either there is an intake leak after the maf sensor.
Exhaust leak before the primary o2 sensor.
Or you put the no foul on the front o2 and not the rear.

EzekielOsiris

Ok perfect! I read it all so tomorrow I'm gonna look for any leak or anything that's not tight enough also clean the sensor and see if this solve my problem. I'll let you know thanks

bbsciontc

If it's still there, another option is to reinstall the factory intake, reset the code and see if it comes back. Many of the ebay intakes are improperly sized and prevent the MAF from reading properly. If it it goes away with the factory intake, then you know the CAI was the problem.

EzekielOsiris

That's a good idea. Ok so today I check everything make sure everything was tight and no air leak. I did that with the air intake and also the header and catback exhaust system tomorrow I have to drive like 4hours so it's gonna be the real test drive. I'll let you know how it goes once I come back. Thank you

EzekielOsiris

Ok so I came back the light came back on. That's ok cuz is only the mass air flow sensor, what it means that the Weapon-R CEL Eliminator did the work. I put like 600 miles and there is no code for the O2 sensor. Now like you told me to reinstall the stock air intake that's what I'm going to do to make sure if is the sensor or the after market air intake that's giving me problem. I'll let you know

EzekielOsiris

Today I put the stock intake and for now the CEL stayed off. What it means that the MAF sensor it's working. I really want to use the intake that a bough how can I fix this issue cuz last time I make sure everything was on place. Is it because there is more air so the CEL will come on every time or there's a way that I can fix it ?

bbsciontc

The problem is the intake design, not the extra air. The ebay ones kinda sucked like that. You should get one from a reputable brand, like Injen or similar. I ran an Injen for like 7 years, never an issue.

xile6

Yes more air coming in.

The stock sensor is calibrated to 2.5 pipe size. Most after market are 2.75 (some name brand ones have a reducer around the maf pipe.)

If there is no reducer it will read incorrect amount of air.
I tune mines with the aem fic (since im going turbo)
Found out it was running lean.
Had to scale the maf sensor voltage up so it read the correct amount of air.
After doing that my AFR and fuel trims where much better.


So does your intake have a reduce part where the maf sensor goes?
Is your intake leaking anywhere?

EzekielOsiris

No, it doesn't have a reducer or anything. Is there any idea on how I can reduce the space my self ?

xile6

They use to sell inserts for maf sensor a while back but i havent look into it.
Might be easier to get a pioe with a reducer already build on it.

EzekielOsiris

Thank you so much! That was my issue the tube was 3 inches so I reduce it to 2.5 inches and the cel is gone I have drive for more than 250 miles and is working awsome. Thank you for all your help and everyone that try to help me.