Hey guys, Ive had this rather strange issue for a few years now, but never really got to the bottom of what it is, wondering if any of you have any ideas, or have discovered the same sound from your own car. The scenario - car parked in my garage, engine off. Every 60-90 sec I hear a 2-3 second long sound coming from the car, its hard to pinpoint exactly where it is coming from but seems to be more towards the middle to back end of the car. The sounds reminds me of pressure built up and then releasing, just sort of a medium pitch wine or groan. The only thing I can think of is possible fuel vapor lock and escaping, but the car will do this for days or weeks at a time. Crazy shit Any ideas?

 

my car did that after I put in a new block. My noise only lasted a week or two, but it was the exact same noise as you describe. I never really found the source but I was positive it was either the cooling system or the fuel system as I had opened up both systems to install the new engine block. I bled the cooling system a couple more times after that and I used to open the gas cap and reinstall the cap whenever I heard the noise, the noise eventually went away.

Did you ever open up the cooling system prior to the noise starting ?, if so you could have an air pocket in it, if not then I'd suspect your fuel system. On the fuel system check to see that your fuel cap tightens down all the way. Also, when you fuel up don't over fill the fuel tank, always stop filling at the first click. I used to have a habit where I would keep filling after the first click of the pump and it may have been dumping raw fuel into the vent pipe of the fuel filler neck.

 

Is it like a humming noise?

 

my girlfriends car does this too! i thought i was crazy. hers is a 2000 accord v6. it still makes the noise even with the battery disconnected too. I cannot for the life of me figure it out!

edit:also her gas gauge doesn't work....

 

Yes sort of a humming groan. Like an old sick lady gasping for air

 

Yea I have it too. Seems to be coming from the fuel canister area.

 

Very interesting, thanks for the feedback on this. Yes I have done all of the above in the last few years, replace motor, replace radiator. Seems like my suspicion and what you described about air pockets in the fuel system seems the most likely culprit for the area the sound is coming from, more towards the back.

Now if so, I'm just wondering if it could possibly be causing any corky running behavior. I get what seems like vapor lock after the car runs for some time and I go back to start it after it sits for a bit. The afrs go lean and the car chugs and surges for a few minutes like its starving for fuel, sometimes it will throw a multi cyl misfire code and sometimes not. It will eventually clear up and run fun after it sits at idle working through the issue for a coupler minutes. If I step on the gas it will clear up a little faster, but that's usually when it throws a cel so I just let the car sort itself out. Just wondering if this sound could be related. My plan was to install a fuel pressure gauge on the rail to see if it is indeed starving for fuel/pressure when it does this.

 

Ahh! I suspected this as a potential as well. Interesting to hear some others are having the same weird thing going on. Its been a wile since Ive inspected this unit wile doing other work under the car, I think I moved it out of the way on my last diff instillation. I think there is some vac hoses that go to this so maybe its under pressure and purging air? I dont really know what this thing does exactly. Wonder if it could just be removed? Or maybe it needs to be fix or replaced.

 

mine does it too... perhaps its the return system of the fuel setup? since our pump "primes" when we put the key it, it sounds like it settles out or something. But mine does it when the car has sat for a while. I can walk past it and hear it occasionally.

 

Well then, its starting to seem like a pretty (normal?) occurrence. Maybe Billman has some insight on this.