# Starter motor humming does not stop; Car starts fine



## EricSmit (Dec 21, 2016)

That's not the starter motor humming, that's your fuel pump priming. Just for what it's worth.


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## anthonysmith93 (Jul 15, 2015)

Yep starter doesn't make noise until you're starting it lol


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## EricSmit (Dec 21, 2016)

Did you recently refill your vehicle? Was it low on fuel? There are a lot of things it could be, from a clogged fuel filter to a faulty pump; what we really need to know is how the car behaved after it started.


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## jblackburn (Apr 14, 2012)

Probably the vacuum assist pump for the brakes.

Does it sound like this?


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## Do_Will (Jul 15, 2016)

Oops ! I feel stupid ! Yes, the fuel pump priming. Sorry ! The car does seem to be running fine. It is not low on gas. It was filled 3-4 days ago. I will watch how it is running.


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## Do_Will (Jul 15, 2016)

jblackburn, on your video, were you referring to the sound at the last 2 seconds of the video? I think that is what I hear. I will check again tonight.


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## jblackburn (Apr 14, 2012)

Do_Will said:


> jblackburn, on your video, were you referring to the sound at the last 2 seconds of the video? I think that is what I hear. I will check again tonight.


You (I) can hear it throughout the entire video when I hit the brake pedal.

If the little pump is constantly running, there's a vacuum leak to the brake booster somewhere. It should build up a vacuum, then shut off.


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## Do_Will (Jul 15, 2016)

No, it is not the brake assist vacuum. I don't have to hit the brake pedal to get the noise. I don't hear it after the engine starts (or it blends into the engine noise). It is almost like the fuel pump starts priming and doesn't stop. The car runs fine, so I am going to ignore it for now.


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## Merc6 (Jun 8, 2013)

Have you had the HVAC reset yet? What you describe kinda sounds like it could be the #PI below. For me I could hear it with the car on and off if it's a quiet night or inside an enclosed area(garage). The brake booster pump I never really hear unless i'm pressing on the brakes between windows 1 and 2 of a drive thru with the window still down. 

#PI1267 High Pitched Whine or Buzz Noise From Engine Compartment After Engine is Turned Off.


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## Do_Will (Jul 15, 2016)

No, it is not PI1267. This is only before starting the engine. There is no noise after stopping the engine. And, air conditioner is off.


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## Do_Will (Jul 15, 2016)

I have tracked the noise down to the vacuum assist pump. 
Thanks, jblackburn. You were right.

The noise is from the vacuum assist pump. I hear the noise when the key is in START position (engine not started; brake not pressed). The noise stops after starting the engine. Then, I can hear it momentarily when I pump the brake. It stops immediately afterwards. Doesn't sound like it is continuously running (once the engine is started).

Could this be a bad vacuum assist pump? Could it be a leak? Wonder why it is constantly running before the engine starts.


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## jblackburn (Apr 14, 2012)

Do_Will said:


> I have tracked the noise down to the vacuum assist pump.
> Thanks, jblackburn. You were right.
> 
> The noise is from the vacuum assist pump. I hear the noise when the key is in START position (engine not started; brake not pressed). The noise stops after starting the engine. Then, I can hear it momentarily when I pump the brake. It stops immediately afterwards. Doesn't sound like it is continuously running (once the engine is started).
> ...


If it stops once engine is started, and only runs when brake is pressed that is normal.

Running while off - I'd suspect a bad check valve in the line to the brake booster or the little vacuum "reservoir".


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## Do_Will (Jul 15, 2016)

Pete, thank you very much. Any chance, you can get me the part number (or the official name) ?
Is it #15 on this diagram - HYDRAULIC SYSTEM for 2012 Chevrolet Cruze ?

Thank you !!


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