There's a monster in my hatch!

[gs1000kat]

Or so it sounds. If I let the car sit for about 20-30 minutes and then restart it, there is a roaring kind of sound for a few seconds. It kind of sounds like maybe the fuel pump purging or something like a blast of air or liquid into a liquid. but I'm not sure. I've never heard it before on any previous 3S or any other car I've owned.

The car is a 91 with a 93 engine, harness and ECU. Only mods are Greddy Profec B, vacuum reduction and K&M air filter.

Anyone ever experience this?

*EDIT* So I havent found the issue yet, but a better description of the noise is that of worn brake pads grinding on the rotor. Not quite as loud, but a similar sound. It's obviously not that since I am not driving at the time. I also dont believe the sound is anything grinding, just the sound is similar.

[Steve '92ES]

Do you have active exhaust? If so try putting the switch in the other position. In one position, I forget which, it goes through a selftest kind of thing when you start the car, opening and closing the baffle.
I can hear the motor running in my TT, but I wonder if you might have a hole in your exhaust making it sound different.
Just a thought...

[Emilie@GZP]

only stuff that is back there, is the ecs computer, and the fuel pump. so, it's most likely something to do with your fuel pump. I'd get that checked out.

[stealthee]

only stuff that is back there, is the ecs computer, and the fuel pump. so, it's most likely something to do with your fuel pump. I'd get that checked out.

You forget about the AA motor, the Active exhaust motor, and the power antenna.

[gs1000kat]

It doesn't do it every time though. It's usually hafter it's warmed up then sits for 20-30 min or so. then I restart it. I'll have to see if I can have my wife start it for me one of these days a nd hope it does it.

[Emilie@GZP]

You forget about the AA motor, the Active exhaust motor, and the power antenna.

doubt the AA or antenna would make a sound like what he's describing. bad antenna sounds like a garbage disposal, and the AA... just "clunks" when it moves.

[DocWalt]

I'm pretty much 95% sure it's your active exhaust motor. I bet you're just not hearing it on initial startup because the engine revs a lot higher when it's cold.

[93STLTH]

Just throwing this out there, but if you have an exhaust system that is using 2 different types or thickness of metals, they will expand and contract at different rates. Part of your exhaust might be cooling enough to give you a gap in the system until either they both heat up or cool down to the same size.

[PTrain]

I have the same noise every once in a while. It's defiantly not the active exhaust since I have an aftermarket system. I also don't think it's the differences in exhaust material.

I'm betting fuel pump. I don't know what it means though.

[DocWalt]

The active exhaust motor will make noise unless you unplugged it.