What is this noise?

Joined
4 April 2011
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Location
Fountain Hills, AZ
Super Car Sunday was a blast being out there with all those other NSXs. Seeing everything from bone stock to full blown race. So I needed to be at my best. Funny thing is the my rear brakes have been squealing since I bought the car. The previous owner had replaced all the brake pads but after 2k miles I still had this bad squeal.

So I get home yesterday after the big ride and decide to take a peek at the rear brakes. Pull off the wheel and calipers and pull out the pads. First think I notice is the inner and out pads have different shims. The next thing I notice is the inner pad is wearing unevenly from inside to outside of the pad. I notice there is a rivet in the top middle of the pad and there is a hole in the shim that this rivet extends out further than the shim. Hmmmmm.

So I look back at the piston in the caliper and see an X cut into the piston. I look some more and see where the rivet had been sitting, was not in the grove but on the face of the piston, causing the uneven wear and probably the squeals. I rotate the piston so that the rivet will drop into the grove and button up that brake and wheel. Did the other side and the same thing was going on there. So I fixed that one too. But that is not what this thread is about.

While working under the car for about 90 minutes, about every 10-15 minutes I would hear a noise from somewhere in the motor area. I could never really identify what the noise was. I was thinking fuel pump, maybe something with my car alarm, I just don't know. It was a humming noise like a pump or electric motor. But it kept going on, would run for about 5-10 seconds then turn off. Has anyone else had this happen to them? What is this and is it normal?

Oh yeah, my brakes are now silent and perfect.
 
If the engine is not running and the key is not ON, you shouldn't hear anything in the engine bay. Alarms don't normally have motors. You're going to have to put your listening ears on and track it down. NOT normal.
 
Crap, that is what I thought. It would go on for over an hour but not drain the battery. Weird. Anyone else?
 
Crap, that is what I thought. It would go on for over an hour but not drain the battery. Weird. Anyone else?

Do you still have the stock antenna? I had one go bad on another car and it was almost as if it didn't know the antenna was all the way down so the motor was continuing to engage. Eventually, it drained the battery.

It may not be the problem but it's another electric motor in the vacinity.

Cheers,
Ian
 
I took the stock antenna (still working) out of the car and replaced it with a Shark antenna so that is not it. I'm pretty sure it was coming from down low in the car so that what got me to think it was the fuel pump. It has done this several times while cooling down so it's not a one time thing. It also does not go on for more than an hour or so, so it doesn't drain down the battery at all. Weird huh?
 
another unusual noise is crankcase venting,but it is more of a moan,or whale sound.
 
Next time you are experiencing this sound, try unscrewing the gas cap and see if it goes away. I had a car that would make crazy sounds when it had less than a quarter tank of fuel. The pressure was causing something in the system to make weird sounds.

My $0.02
 
If the engine is not running and the key is not ON, you shouldn't hear anything in the engine bay. Alarms don't normally have motors. You're going to have to put your listening ears on and track it down. NOT normal.

This isn't necessarily true. To Docs point above, engines make all kinds of sounds, sometimes long after they're off.

Sometimes it is systems that are deliberately timed to go off (not on the NSX necessarily, but things like turbo timers, fans etc) and other times it is simply mechanical noises (things venting, cooling, settling)

Really need more detail on what the noise is (like a sound clip - record and upload to YouTube)
 
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That is what I thought also. Maybe the crankcase venting or the gas tank venting. Next time I take it out, I'll park it in the garage and sit out there with a beer so I can spend some time listening. Damn, what a chore!
 
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