2004 to 2016 Mazda 3 Forum and Mazdaspeed 3 Forums banner

21 - 40 of 44 Posts

·
Registered
Joined
·
979 Posts
@sc489, I have the same sound after I turn OFF the engine (less distorted tough). Do you have any third party anti-theft system / box that is hardwire and requires some voltage after turning off the engine? (Picture below)

*But, I can also hear this sound when the I press ignition ON and I do NOT start the car, so it might be related to some component of the ignition system.

This is my most logical assumption since I have the anti-theft box under the hood, and I think that is where the sound is coming from.

Second assumption might be the radiator fans, although they don't sound as the audio file that you provided, it's a very subtle sound when they are running after the engine is off.

But by all means and purposes IMO I think this sound is totally normal. If somebody can clarify what is this sound It would be very helpful to solve the mystery.
 

Attachments

·
Registered
Joined
·
661 Posts
Discussion Starter #23
@sc489, I have the same sound after I turn OFF the engine (less distorted tough). Do you have any third party anti-theft system / box that is hardwire and requires some voltage after turning off the engine? (Picture below)

*But, I can also hear this sound when the I press ignition ON and I do NOT start the car, so it might be related to some component of the ignition system.

This is my most logical assumption since I have the anti-theft box under the hood, and I think that is where the sound is coming from.

Second assumption might be the radiator fans, although they don't sound as the audio file that you provided, it's a very subtle sound when they are running after the engine is off.

But by all means and purposes IMO I think this sound is totally normal. If somebody can clarify what is this sound It would be very helpful to solve the mystery.
The car is a standard model with no mods. I hear the same noise when turning the ignition on also but not for so long. I'm guessing it's something to do with the fuel line pressurising.
 

·
Registered
Joined
·
158 Posts
The car is a standard model with no mods. I hear the same noise when turning the ignition on also but not for so long. I'm guessing it's something to do with the fuel line pressurising.
I agree its probably fuel related. The main fuel pump is in the gas tank, I believe. But our cars have very high pressure at the injectors. There's probably an additional pump/booster close to the injectors. It may be acting in reverse to relieve the pressure when it powers off.
 

·
Rubber side down
Joined
·
243 Posts
That noise would be the fuel pump.
Now that i've listened to the recording, it does sound like a fuel pump. My car makes that sound as well. Initially I thought it was the HID ballasts humming but since there are people hearing the sound on models without HIDs, then I would go with fuel pump. Can someone confirm and give arathol his prize?


Disregard my initial guess of 'something that sounds like a fan'. I hadn't paid a lot of attention to it in a while so I got my sounds confused. :001_rolleyes:
 

·
Registered
Joined
·
661 Posts
Discussion Starter #27
Noise source solved - I think!

I sent the recording to my dealer who reported - The noise you are experiencing is the flap motor on the intake throttle body recirculating. Perfectly normal and identical to the vehicles we have on site.

No prizes since nobody suggested this! Let's see who disagrees.
 

·
Registered
Joined
·
718 Posts
Noise source solved - I think!

I sent the recording to my dealer who reported - The noise you are experiencing is the flap motor on the intake throttle body recirculating. Perfectly normal and identical to the vehicles we have on site.

No prizes since nobody suggested this! Let's see who disagrees.
I took a look yesterday, had never heard it before because it is so subtle. I turned the ignition on, turned it off and listened under the hood. It's the same sound the OP posted, very low db humming sound and it sounds like it is coming from the front part of the engine block just behind the fans, but it definitely isn't the fans. Mine is a 2014 2.5 with automatic.

What exactly is the flap motor?
 

·
Super Moderator
Joined
·
5,185 Posts
I took a look yesterday, had never heard it before because it is so subtle. I turned the ignition on, turned it off and listened under the hood. It's the same sound the OP posted, very low db humming sound and it sounds like it is coming from the front part of the engine block just behind the fans, but it definitely isn't the fans. Mine is a 2014 2.5 with automatic.

What exactly is the flap motor?
I was in the car today looking for a similar sound. From inside, there is no noise except what sounds like the steering solenoids locking about 2 seconds after shutdown. Under the hood, and only when the power is on without the engine running, there is a very faint buzz coming from the throttle body control motor, and it stops as soon as the power is shut off. Perhaps that is what the dealer is referring to? I don't know why it would be running so long after the power is shut off though, so it doesn't really match up with the original question.

 

·
Registered
Joined
·
151 Posts
Noise source solved - I think!

I sent the recording to my dealer who reported - The noise you are experiencing is the flap motor on the intake throttle body recirculating. Perfectly normal and identical to the vehicles we have on site.

No prizes since nobody suggested this! Let's see who disagrees.
It's EHPAS:
I have to disagree. I hear this noise on my 2010 Mazda3, which is equipped with "electronic hydraulic power assisted steering" (EHPAS). Look under the hood and you'll find a reservoir for power steering fluid. Commenters with a 2014 Mazda3 and later have fully electronic power assisted steering (EPAS) -- meaning no fluid and no tubes -- and will never hear that sound.

After starting my car, if I nudge my steering wheel left or right, I will briefly hear the buzz. Coming home after a long drive and shutting off the engine, I also hear the noise, for perhaps a full minute. I'm not sure why this happens, but I suspect it's related to circulating the steering fluid on startup and shutdown. Anyway, this noise is normal, and kind of cool.

Tidbits:
Ford models on the C1 platform (e.g.: Ford Focus 2008-2012) also make this noise. The C1 platform is a shared and joint effort by Ford, Mazda, and Volvo. In EHPAS, it's the hydraulic part that gives these Mazdas superior steering feel. Of course, gen1 Mazda owners can claim to have the best steering feel because their racks were moved 100% by hydraulic steering. However, they pay a fuel efficiency penalty. That said, electronic steering has gotten pretty good nowadays, and Mazda and Porsche are among the best in electronic steering.
 

·
Registered
Joined
·
310 Posts
From the owners manual:


"After driving some distance and turning off the engine, the sound of a valve opening and closing can be heard at the rear of the right side of the vehicle, however this does not indicate an abnormality. Your vehicle has a self-checking device and it operates after turning off the engine."

I hear it on my 2014 2.5L Mazda3 and on my 2009 Highlander. It's the same hum and an subtle valve like sound after shut down, even if I didn't start the engine. Seems to be self-diagnostics.
 

·
Registered
Joined
·
661 Posts
Discussion Starter #32 (Edited)
It's EHPAS:
I have to disagree. I hear this noise on my 2010 Mazda3, which is equipped with "electronic hydraulic power assisted steering" (EHPAS). Look under the hood and you'll find a reservoir for power steering fluid. Commenters with a 2014 Mazda3 and later have fully electronic power assisted steering (EPAS) -- meaning no fluid and no tubes -- and will never hear that sound.

After starting my car, if I nudge my steering wheel left or right, I will briefly hear the buzz. Coming home after a long drive and shutting off the engine, I also hear the noise, for perhaps a full minute. I'm not sure why this happens, but I suspect it's related to circulating the steering fluid on startup and shutdown. Anyway, this noise is normal, and kind of cool.

Tidbits:
Ford models on the C1 platform (e.g.: Ford Focus 2008-2012) also make this noise. The C1 platform is a shared and joint effort by Ford, Mazda, and Volvo. In EHPAS, it's the hydraulic part that gives these Mazdas superior steering feel. Of course, gen1 Mazda owners can claim to have the best steering feel because their racks were moved 100% by hydraulic steering. However, they pay a fuel efficiency penalty. That said, electronic steering has gotten pretty good nowadays, and Mazda and Porsche are among the best in electronic steering.
It can't be EHPAS as you suggest. This is the 2014-17 (now 18!) Mazda 3 thread and we all have electric power steering. There is no hydraulic assistance.
 

·
Registered
Joined
·
661 Posts
Discussion Starter #33
From the owners manual:


"After driving some distance and turning off the engine, the sound of a valve opening and closing can be heard at the rear of the right side of the vehicle, however this does not indicate an abnormality. Your vehicle has a self-checking device and it operates after turning off the engine."

I hear it on my 2014 2.5L Mazda3 and on my 2009 Highlander. It's the same hum and an subtle valve like sound after shut down, even if I didn't start the engine. Seems to be self-diagnostics.
Those words are not in my full 2017 owner's manual and the noise is clearly from the engine bay, not the rear. See what my dealer said in post 27. I do wonder though why the noise persists for about 40 secs.
 

·
Registered
Joined
·
151 Posts
It can't be EHPAS as you suggest. This is the 2014-17 (now 18!) Mazda 3 thread and we all have electric power steering. There is no hydraulic assistance.
I stand corrected; I see the OP has a 2017 Mazda3 UK spec. We're all missing a piece to this puzzle. I downloaded the .wav file and recognize the sound though. It comes from the front, and occurs when I move the steering wheel on startup, and when I shut off the engine. It has to be a common component carried over from the 2010 model to the 2017 model... although not all owners reported hearing this.

OP: can you please check under your hood and look for a power steering reservoir? :smile2:
 

·
Registered
Joined
·
661 Posts
Discussion Starter #38 (Edited)

·
Registered
Joined
·
13 Posts
My 2017 GT (automatic with tech and safety packages) does this as well. It sounds just like the .wav file. It does this every time I shut it off (or at least I can hear it when getting home at night with no other noise around, it's subtle and you can't really hear it with ambient noise around). It lasts 30-45 seconds then stops. I'm curious as well what it is.
 

·
Registered
Joined
·
718 Posts
All I did was turn the ignition on then turn it off and I get the noise.

Here is an "Mazda 3 intake Manifold Solenoid Air Flap Actuator Control Valve" Could this be the culprit?

 
21 - 40 of 44 Posts
Top