brown stain coming from breather inlet in my CAI

blkspeed

Member
title says it all im haveing a ongoing issue with my running rich at idle CEL with low idle speed 500-400rmp. it has never stalled on me yet since then i did a induction cleaning, new sparks, and cleaned the MAF. aswell as taking the whole intake out and putting it back together. but i noticed a brown stain in the inside of my CAI smells like gas-oil mix also see condensation in there as well. and is all coming from the breather tube inlet. im wondering whats going on. also noticed that modded cars put a tiny filter on the breather inlet instead of running it through the intake.

my guess to the cel is the EGR but i wanted to get this issue above noted before i do anything else
 
The breather tube is the crank case ventilation and its normal to see oil fumes in the intake with the breather connected to it. Its made that way to help with emmisions. Adding a catch can would solve the issue(witch is not really one in fact).
 
The breather tube is the crank case ventilation and its normal to see oil fumes in the intake with the breather connected to it. Its made that way to help with emmisions. Adding a catch can would solve the issue(witch is not really one in fact).

by the oil fumes do you mean stains as well? looks like the "oil" if that what it is, was running out the breather tube and into the intake and its hard to remove very gummy
 
That is perfectly normal. The system is designed to suck that crap in to the engine to burn it however our car's PVC system seems to be plagued with an abundance of what you describe as "oil/gas mixture". Basically it is oil/condensation and whatever else gets in to our engines trying to make it's way to our intake tracts.

As mentioned, a catch can setup will stop the oil mixture from running down your intake.

As for your running rich at idle CEL, I have no idea what your problem would be. Sorry man.

EDIT: What CEL are you actually throwing?
 
That is perfectly normal. The system is designed to suck that crap in to the engine to burn it however our car's PVC system seems to be plagued with an abundance of what you describe as "oil/gas mixture". Basically it is oil/condensation and whatever else gets in to our engines trying to make it's way to our intake tracts.

As mentioned, a catch can setup will stop the oil mixture from running down your intake.

As for your running rich at idle CEL, I have no idea what your problem would be. Sorry man.

EDIT: What CEL are you actually throwing?

donno the code but it reads out "rich at idle" everythings great when i drive but when i sit there the rpms hang out a 500-400 but i dont stall out

the only thing i havent done is catch can and checking the EGR
 
...also noticed that modded cars put a tiny filter on the breather inlet instead of running it through the intake.

People that do that don't understand how crankcase ventilation works. That will introduce an air leak in the system and screw up the fuel trims, especially at idle.

Air that is sucked in the breather tube (breather tube -> crankcase -> PCV valve -> intake manifold) must be metered by the MAF. That's why the breather tube is connected to the intake post MAF.
 

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