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Old 09-26-2012, 10:02 PM   #1
Myth21
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Default What is the noise from when you first start your WRX??

I notice when I first start my car I hear a loud, suction type of noise that lasts for maybe 10 second then the car gets quieter.

I am trying to figure what that is from, because there is some other weird noise when I roll away and I think it may be associated with it.

PS: 2012 WRX
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Old 09-26-2012, 10:03 PM   #2
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I believe the newer boxer motors have an air pump. That maybe the noise you hear upon startup.
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Old 09-26-2012, 10:07 PM   #3
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Without a video it's hard to pinpoint. Subaru's are noisy. It could be the fuel pump, it could be almost anything. You really don't hear the air pump, and they do not always run during startup.
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Old 09-26-2012, 10:14 PM   #4
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Could be the fuel pump, sounds more likely. It gets pretty dead quiet and all I hear is the engine idle after 10 seconds or so.

The reason I am asking is because I sometimes hear a metal scratching noise, and sounds like it's spinning at the same time when I take off slowly. I am hoping it is not the bearing because the car drives great and I am not hearing a loud vibration or humming noise at high speed like I would if it was a bad bearing.

And I doubt it's anything with the clutch...I had the passanger side bearing replaced few month ago because I slid into a guard and that was obvious. The wheel was wiggly when lifted.
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Old 09-26-2012, 10:25 PM   #5
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Air pump
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Old 09-26-2012, 10:51 PM   #6
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I second the air pump. When they start letting go, they can make a bit of noise. Mine is at that stage right now.
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Old 09-26-2012, 11:02 PM   #7
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Could it be the ABS self-check? Every time the car starts, the ABS system goes off as a diagnostic...sounds like the "scratching" noise you're hearing. Happens every time I get the car moving after starting it up.
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Old 09-26-2012, 11:07 PM   #8
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Quote:
Originally Posted by RuinerXL View Post
Could it be the ABS self-check? Every time the car starts, the ABS system goes off as a diagnostic...sounds like the "scratching" noise you're hearing. Happens every time I get the car moving after starting it up.
That sounds like it too, the noise sounds like a hollowed grinding like "dunnnnnn, dunnnnn" as I roll off the first 2 seconds...but does it sound like metal..?
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Old 09-26-2012, 11:12 PM   #9
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Like others have indicated, it would be tough to pinpoint the sound without a video of some sort, but I do know that my car produces a sort of grinding sound for a very short duration when getting it going after starting, which is due to the above mentioned ABS check.
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Old 09-26-2012, 11:22 PM   #10
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But I hear it not only at intital start but during in between on/offs as well. And I tend to hear it everytime I'm in some kind of covered drive thru...lol
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Old 09-26-2012, 11:24 PM   #11
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Here is your answer =

It is your air pump. You will hear the drone from the pump and the thudding sound in the cylinder heads and intake.
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Old 09-27-2012, 02:58 PM   #12
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air pump
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Old 09-27-2012, 10:23 PM   #13
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It's the air pump!
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Old 09-27-2012, 11:39 PM   #14
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My air pump sound presents itself as a loud rattling sound coming from the exhaust after a cold start. Sounds really like a loose heatshield or something under the car or inside the muffler. Stops when the air pump turns off after a minute or so, or if I blip the throttle a bit to rev the engine gently. I have a 3" exhaust with the stock muffler (2012 hatch) so I'm hoping this is normal. Is this what others have heard when talking about the air pump noise?
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Old 09-28-2012, 12:27 AM   #15
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Not sure if it was mentioned yet but "air pump".
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Old 09-28-2012, 02:37 AM   #16
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Something that might pump air?
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Old 09-28-2012, 02:43 AM   #17
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To all the morons who posted "it's your fuel pump"... you kids are buckets of stupid.

plz stop posting.
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Old 09-28-2012, 08:31 AM   #18
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Quote:
Originally Posted by bdearnley View Post
My air pump sound presents itself as a loud rattling sound coming from the exhaust after a cold start. Sounds really like a loose heatshield or something under the car or inside the muffler. Stops when the air pump turns off after a minute or so, or if I blip the throttle a bit to rev the engine gently. I have a 3" exhaust with the stock muffler (2012 hatch) so I'm hoping this is normal. Is this what others have heard when talking about the air pump noise?
yes this is normal.
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Old 09-28-2012, 05:11 PM   #19
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Quote:
Originally Posted by eronenris View Post
yes this is normal.
Thank you. It's so alarming I'm surprised there isn't more discussion about it on various forums. Faark it's loud! And also surprising that a downpipe and midpipe, which barely makes the exhaust louder when driving can amplify this sound so much compared to the stock exhaust. It would be good if there was a way to disable it with an ecu tweak rather than having to remove it if you want to get rid of it.
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Old 09-28-2012, 11:27 PM   #20
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LOL :-) My air pump sounds like shictz
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Old 09-29-2012, 10:16 AM   #21
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Quote:
Originally Posted by bdearnley View Post
It would be good if there was a way to disable it with an ecu tweak rather than having to remove it if you want to get rid of it.
You can pull fuses when the valves are closed. Also have to clear the CEL codes.
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Old 09-29-2012, 07:22 PM   #22
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Quote:
Originally Posted by Mike 01Hawk View Post
You can pull fuses when the valves are closed. Also have to clear the CEL codes.
Interesting. So I assume the valves are closed when the engine is warm, correct? Also will the CEL keep coming back once cleared? Will the engine run rough or are there any other negative side effects?
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Old 09-30-2012, 10:07 AM   #23
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Warm = closed. CEL codes will have to be erased by a tweak of your ECU. No side effects to performance/mpg/etc, your cats will just be inefficient on start-up which is a moot point if you are now running with a catless DP. Read the Air Pump Delete thread(s)
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Old 09-30-2012, 10:08 AM   #24
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Quote:
Originally Posted by bdearnley View Post
Interesting. So I assume the valves are closed when the engine is warm, correct? Also will the CEL keep coming back once cleared? Will the engine run rough or are there any other negative side effects?
If you "tune out" or turn them off via a tune, they will not come back. If you simply pull fuses, they will stay on. The air pump is for emissions only, and DO NOT RUN AT EVERY START UP. (Some people, especially in here seem to forget this) It does not affect how the motor runs. There is an entire thread about removing the air pump on 06+ motors, read it.
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Old 09-30-2012, 04:20 PM   #25
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Quote:
Originally Posted by Mike 01Hawk View Post
Warm = closed. CEL codes will have to be erased by a tweak of your ECU. No side effects to performance/mpg/etc, your cats will just be inefficient on start-up which is a moot point if you are now running with a catless DP. Read the Air Pump Delete thread(s)
Quote:
Originally Posted by HinshawWRX View Post
If you "tune out" or turn them off via a tune, they will not come back. If you simply pull fuses, they will stay on. The air pump is for emissions only, and DO NOT RUN AT EVERY START UP. (Some people, especially in here seem to forget this) It does not affect how the motor runs. There is an entire thread about removing the air pump on 06+ motors, read it.
Thankyou both. I will think about doing this.
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