I am just curious where my engine air filter is taking air from.

Below is a picture of my car's (Toyota Vitz 2007) engine (not a picture of my exact engine).

enter image description here

As I can see, the air filter should take air from the place I have circled in red. If I block air intake with my hand, engine doesn't even seem to notice it. If it was actually the place the engine takes air from, I would expect the engine to stall when I block it.

So isn't this the place where the air filter draws air from? If it is, why didn't engine stall when I block it?

  • 2
    I would bet that's not actually where the engine draws air from. Easiest way to tell for sure is to take the cover off and see where the air routes to. The four clips on the left side of the engine cover (right side of picture) is where it would appear the filter would be located. Start there and see if you can figure out the air intake path. It looks like it might actually come from the back of the engine and draw from the cowl. Feb 21, 2016 at 10:52

1 Answer 1


Logically, yes. Putting your hand there, should make the engine struggle but because the pressure inside drops so much when you put your hand there, the air is sucked in through gaps in the air filter housing.

Besides, your engine is probably running better (maybe) because you placing your hand there doesn't entirely kill the engine but simply makes the air-fuel ratio rich (this makes the engine smile).

If you do not feel any suction on your hand at all then you simply have your hand in the wrong place (which, by the looks of it, is not the case).

  • I hardly notice any suction when I block it either. I checked by taking the air filter housing apart and I am pretty sure this is where the air should be taken from.
    – Softcode
    Feb 21, 2016 at 6:43
  • When you take the air filter housing apart, you should be able to see the air in take. Do you feel any suction there?
    – krthkskmr
    Feb 21, 2016 at 7:40
  • I think you are correct. Air should get sucked in through gaps between the cover and the engine. I removed the cover and blocked the intake into the throttle body and I felt significantly higher suction.
    – Softcode
    Feb 21, 2016 at 11:32
  • 2
    Blocking the intake won't make the AFR rich. Reduced air intake will be compensated by reduced fuel injection. Feb 22, 2016 at 10:52
  • To compensate for the lack of air, and to bring the rpm back up, the ECU will make the AFR rich.
    – krthkskmr
    Feb 22, 2016 at 19:09

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .