Odd noise coming from engine bay????

rdwngs444 · 08-24-2009, 07:54 PM

I have 9k miles on my 08' FJ, my truck has been in the garage for about 5 hours and i went out there and it was like a fan or a pump was on??? It turned off after about a min but it was making noise before i went out there so i don't know how long it was making noise. Any ideas? Seems like it was coming from the front of the engine compartment, i do have a trd supercharger if that has anything to do with it.

ejgdmk · 08-24-2009, 07:57 PM

I read something about that in the owners manual, if I remember right without getting the manual out it has something to do with the fuel pump its normal for it to do that

**BlackCherryota** · 08-24-2009, 08:08 PM

Quick answer: it's a compressor-type pump that is used to pressurize the evaporative emissions system. Consider it normal. Others will hopefully chime in with a better answer.

**JoeUser** · 08-25-2009, 11:55 AM

Don't know if this helps, but FWIW:

Fuel pump noise ?

**cnckart** · 08-25-2009, 11:59 AM

Normal. It's all the emissions crap doing a self test.

**JoeUser** · 08-25-2009, 12:09 PM

Of course, if you're really stumped, you can call Father Branegan, he might be able to help:

kokopelli · 08-25-2009, 12:26 PM

They do that.. Several posts over the years relating to it.. Not to worry.. Cheers.. ron

PS; You didn't leave the supercharger turned on did you? It'll kill your battery

.. Just kidding/joking..

rdwngs444 · 08-25-2009, 08:40 PM

Is it odd that is does it so many hours later?
Oh and my supercharger is always on!!!

**DEWFPO** · 08-25-2009, 08:54 PM

Quote:

rdwngs444 previously said:

Is it odd that is does it so many hours later?

Nope, it's designed that way. Everything cools off and stabilizes (to some degree) before the test runs.

DEWFPO

**RoverGGM** · 08-25-2009, 09:18 PM

The evaporative emissions system's self check begins approximately 5 hours after the vehicle is shut down....unless the fuel tank temp is above 92 degrees, in that case the system checks approximately every 2 hours until the tank temp drops below 92 degrees.

It's basically a vacuum pump that checks for leak down in the fuel vapor control system. It helps prevent evil fuel vapors from escaping your tank and "polluting" the surrounding air, by capturing them and routing them through a charcoal canister mounted under the rear of the vehicle. This canister is purged during the next drive cycle.

The FJ is also equipped with a charcoal filter attached to the inside of the intake to prevent evaporative emissions from escaping there.

(Thank EPA and CARB)