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Electric vacuum sound from engine bay

Old 03-23-2016, 06:58 PM
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Saibot
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Default Electric vacuum sound from engine bay

Has anyone ever come across this noise before?

I was trying to start the car but after two cranks, it wouldn't crank anymore.

Maybe its a low battery issue? But then I heard this vacuum like sound coming from the engine bay (engine was off, key was not even in the ignition).


(sorry for the portrait upside-down camera)

The little intermittent crackling noise made me almost think there was a short circuit somewhere.

Battery drained down to 10V really really fast, and then died after this.

Thoughts?
Old 03-23-2016, 07:26 PM
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groovzilla
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that crackling noise sounds like a water pump bearing or similar?? sit tight and one of the more mechanically inclined will chime in
Old 03-23-2016, 08:06 PM
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billyboy
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Sounds like it might be the air pump for the pollution control system. It's the black unit to the left in the engine compartment that's shaped like an electric motor (which it is). It usually runs at a higher pitch than that but maybe yours is on the way out. Why it's running with the engine off and the key out is certainly something to check out.
Old 03-23-2016, 08:15 PM
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Mark I
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The two things that coincide, losing electrical power and rotational noise, would point to the alternator. Not saying that's it, just an observation. Remove the serpentine belt and rotate everything by hand; listen and feel.
Old 03-24-2016, 04:54 PM
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Could also be the engine compartment cooling fan on the underside of the decklid. I'm with billyboy, but it should not run with the key out, the cooling fan could. However, the fan would not run when the car is not warmed up. If it is the cooling fan, could be the engine compartment temp sensor or wiring. If it is the SAI pump it gets trickier, this is commanded on by the DME, you could check to see if it is being powered on at the relay. Relays are under the carpet in the rear parcel shelf. Might be a good idea to look at the relays in case there is water or something in there.

http://www.pelicanparts.com/cgi-bin/...EM-99660510301 for the Secondary Air Pump.
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