Alright so I finally got a hold of an OBDII scanner from a friend and checked out my codes. My s40 had thrown two seperate P0172 codes for running too rich.

Any ideas as to what could be causing it?

The background of what I've done to the car is I installed a custom CAI, and I replaced the spark plugs. The code first popped up 3 weeks after I installed the CAI, and it tends to go away for a week and show up for a couple days and go away and continue on in that pattern.

Any help would be great.

 

How long since you replaced the O2 sensor?

 

Whered you get the cai from? K&n"s the only one that won't throw a code but other then that it's a shot in the dark with the codes. I know gdubsdesign and simoto have a 50/50 chance.

 

I've never changed the u2 sensor. I had a feeling it could be the sensor slowly dying throwing the code once every couple weeks.

I built the intake myself and all the vacuum lines and maf sensor and everything is completely sealed and no leaks so I don't understand how the intake could throw the code.

 

I was always under the impression that the MAF sensor could adjust for the slight flow improvement. That is why I asked about the O2. Isn't the classic sign of a bad O2 sensor poor fuel economy as the car runs too rich?

 

No the problem with volvox is there so precise that it doesn't know how to adjust to the new output and there's not a way to reprogram the ECM/ecu

 

But it shouldn't cause more fuel to go in the mix even if it can't adjust itself. It knows it is getting more air and 90% of the time I get good fuel economy. It's once in about 2 weeks it decides to throw a code and put my mileage down the ****ter. And then it goes away on it's own. To me I would think it's something like an o2 sensor going bad since it is intermittent.

 

But your using a homemade intake which is acting more like a RAM intake which is good low end torque and boost but will kill your gas mileage but a cold air intake will give more high end torque when your turbo spools up and boost your mpg. Are you at least using a good filter and heat shield hot air will also destroy your ECM and turbo.

 

I don't have a turbo I have the 2.4i. And it's not a ram intake it's a cold air. The intake goes from the throttle body down into the driver-side of my front bumper. It's not getting any hot air and the ECU is mounted away from the engine as well.

See the attached image.

 

Ok that's good I've seen some where the filter is just sucking in the engine bays hot air but you could also use the stock intake scoops. Im going to try a simtomo intake in a week or so on my 2.4i I just hope a brand name intake won't kick as many codes.

Other than that I can't think of anyway to get rid of your codes I just hope it won't lead to anything serious. How did you make your intake?

 

Yeah so far it's only shown 2 running rich codes so I guess I shouldn't be complaining too much.

I bought mandrel bent steel tubing and cut it down to 2 tubes (I got steel because it doesn't conduct heat as much as aluminum) I drilled a hole for the MAF sensor and welded a plate to it to give it a flat surface to sit on. Then I got a 3/8" steel brake line and welded that in with a hole for the vacuum line. Then I just used 2 cheap 3" intake connectors to connect the intake tubes to each other and then to the throttle body. I painted the whole thing with engine enamel to help keep heat conduction even lower, and I put an Injen AMSOIL dry filter on it.

My car sounds 100 times more powerful, and it also got easily a 10hp increase.

 

That's pretty sick I'm excited to have my intake on by next week.

 

can you make another one