s13 air filter

[a30mayne]

Ok so I replaced my air filter about 2k miles ago and I noticed a dark burn spot. What can this be from?

[compactfean]

Notice on your stock intake the tube that goes from the valve cover to it? That recirculates blowby gases back into the intake. You can rather put a breather on the valve cover (which I don't recommend, because its routed that way to meter blow by gases) or put a catch can in between. I would look into your pcv valve first though because if the pcv valve isn't working properly, it can cause this.

[ricebike]

not really the case:

if you still have the AIV pipe from your exhaust and is plumbed into the airbox, like mine, the AIV one way reed valve is starting to weaken/ carbon buildup & is backfiring into your intake

quick and easy remedy:



if you don't have this AIV valve in your vehicle, then revert back to what compactfean stated

[compactfean]

Sweet info ricebike!!! Totally forgot about the air injection.