So I was swapping out my injectors earlier today. I was underneath the hood when all of the sudden I hear this whirring sound like a motor sounding like it was coming from somewhere beneath the engine. It starts instantaneously and then stops instantaneously about 5 seconds later. My car has been known to make this exact sound before when just sitting in the driveway with no keys in the ignition, and I've always just figured it was the fuel pump priming at random (the car has been known to have electrical gremlins before).

It's odd enough my car has been making this sound in periodic intervals to begin with, but even more bizarre was that it happened this time with the positive battery cable disconnected. I thought I was just hearing things when I first heard it, but my dad came out and it did it again. I don't know if he believed me when I first told him, but when we both heard the sound, I immediately lifted the disconnected positive battery terminal to show him that the sound still happens when there is no power.

It's hard to tell where exactly the sound is coming from--I had always thought the fuel pump, but it sounded pretty close to the engine when I was under the hood. It sounds exactly like an electric motor and it always runs for 5 or so seconds and stops. It tends to do it again after several minute intervals.

I've got no clue on this one.

Any ideas?

 

Possibly the tank pressure control valve equalizing the fuel tank pressure, or Demons of Hell clawing and scraping at the floor pan, trying to get in and rip out your very soul, or at least borrow some CDs.

 

Does this "tank pressure control valve" come on without electrical input? The sound does seem to be coming from the back of the car, and it definitely has a lot of air pressure when I open up the gascap (I hear a huge rush of air into or out of it). Moreso by far than most other cars.

 

It just doesn't get any better than this, does it folks?

 

The tank pressure control valve is completely mechanical. It will do its thing, battery or not. If this is happening frequently, you may have a clogging EVAP canister. Might want to check that out.

 

I have nothing constructive to say. But that was hillarious, lmao.