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What could this noise be?

Riot_Polizei

Comp Engineering Student
:
2002 Mazda Protege5
Hey guys, my car developed an incredibly irritating high-pitched frequency at closed throttle:


Granted, acoustics are hard to make out in an engine bay, but it sounds like it could be coming from the throttle body(?) or somewhere around it. It doesn't sound like a typical exhaust leak, but could it be? It does go away under load, after all.

I've also been told that it almost sounds "electrical", and that it could be a belt, one of the pulley mechanisms, or even the alternator, as the belts spin faster under engine load.

It's got me scratching my head, that's for sure. Any ideas?
 

Riot_Polizei

Comp Engineering Student
:
2002 Mazda Protege5
Anyone? I'm out here again, and I can clude that it's at least independent of the brake booster line, interior electronic accessories such as AC or lights.

**NEW**
It did NOT appear until car was warm up to temp. Drove around without the noise for maybe 2 minutes.

It just sounds like it's coming from the IM and throttle body area.

I got under the car, and that didn't help any. It's loud from far away, and it's loud up close.
 
:
83 RX-7 Gsl, 2000 Mazda Protege LX, 2011 Mazda3 Sport i
Maybe a cracked intake manifold? Mine does that cause my gasket has a small break in on part but mine also only come on at like 4-5k rpm
 
:
Mazda P5
Well it's hard to tell or give advice. If it were me I would just take the day to just take it all apart see if anything is cracked or broken (get the gasket first of course). It might be something loose that may re-seal itself under pressure or something due to that nature. I'm just spit ballin here.
 

Riot_Polizei

Comp Engineering Student
:
2002 Mazda Protege5
Maybe a cracked intake manifold? Mine does that cause my gasket has a small break in on part but mine also only come on at like 4-5k rpm
Haven't seen you in a while! Man I've done so much to my P5 since lol.

Do you mean intake manifold gasket or manifold itself? I only recently installed this IM + MP3 ECU combo, and have destroyed one manifold gasket by neglecting to torque the bolts down properly. A new one was put in with proper torque specs, and that middle plenum gasket was still fine. Could the throttle body gasket also whistle?
 

Riot_Polizei

Comp Engineering Student
:
2002 Mazda Protege5
Solved!

A bolt, yet again, wasn't torqued properly on the IM, and the throttle body's bolts were not torqued.

The whine is gone, and now my LTFT and STFT measurements have returned to normal. I'm rejoicing!
 

pcb

The Diagram Dude
:
2002 mazda protege 5
You could probably ignore/postpone the fuel filter now.

Somebody was obviously in there so there's a good chance it's all new components inside.
 

pcb

The Diagram Dude
:
2002 mazda protege 5
Are there things you can monitor to see if the fuel system is operating properly ?
 

Riot_Polizei

Comp Engineering Student
:
2002 Mazda Protege5
Are there things you can monitor to see if the fuel system is operating properly ?
Yessir, using Torque Pro, I set up two meters for LTFT and STFT. Really handy to investigate P0171!
 

pcb

The Diagram Dude
:
2002 mazda protege 5
Here's a list of the codes you could pop where "clogged fuel filter" or "fuel pump malfunction" are listed as a possible cause.

P0131, P0132, P0133, P0171, P0300
 

pcb

The Diagram Dude
:
2002 mazda protege 5
Your welcome.

It's getting me to learn how to work my phone and search a PDF file.
 

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