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Old 07-21-2012, 11:10 PM   #1
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Default Strange whining/electrical humming noise in engine bay

I recently installed my engine back into my car and I came across this strange whining/electrical noise. It only makes this noise when the ignition is set to ON. No sounds at all when on Accessory. I haven't gotten the engine running yet so I can't comment of the noise with the car running. It seems to be coming from around the intake manifold side of the engine. Its really prevalent around the throttle body/TPS area. I do have my TPS unplugged and I am running the DIYPNP if it makes a difference. Could it possibly the the alternator or starter? I tried unplugging the alternator but no difference was observed. I've included a link the sound clip. Any advice? Thanks.
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Old 07-21-2012, 11:47 PM   #2
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That sure sounds strange. Is your voltage OK? If it's low, relays, solenoids etc. could make humming sounds.
If voltage is ok, unplug everything (like VICS etc.) and re-plug one-by-one.

Just stabbing in the dark here....
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Old 07-21-2012, 11:50 PM   #3
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Sounds like something with a coil beginning to hate life I could look at any relays, solenoids, and motors.
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Old 07-21-2012, 11:58 PM   #4
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Relay in buzzer mode. Something is shorting.
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Old 07-22-2012, 12:27 AM   #5
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Well the car has been sitting for a few months. When I measured the voltage, it was under 12V, about 11.8V ish. I don't know if that would make a significant difference or not. I also notice I get a clicking sound from under the steering column when the key is at on. Its about 3-4 clicks about 5 seconds apart, then it goes away. I found an unconnected plug but I cant find any associated receptacle. Ill try to get a picture of the unconnected plug when its daylight.
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Old 07-22-2012, 06:08 PM   #6
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I think I narrowed to down to the IAC connector. When plugged in, it emits the humming sounds, when disconnect its perfectly normal. I measured the resistance at the IAC valve and it was within spec and the voltage at the connector was a little under 12V. I did some quick searching and the humming could possibly be related to the DIYPNP? I think I read there is a setting in the Idle Control menu that could possibly allow me to adjust the frequency of this thing? Am I headed down the right path?
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Old 07-22-2012, 06:21 PM   #7
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you have the wrong freq. in your tune for your idle valve.


didn't read thread.
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Old 07-23-2012, 04:29 AM   #8
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Quote:
Originally Posted by Braineack View Post
you have the wrong freq. in your tune for your idle valve.


didn't read thread.
Didn't finish reading OP, didn't watch video or read thread, agree with above.
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Old 07-23-2012, 09:41 AM   #9
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Quote:
Originally Posted by Braineack View Post
you have the wrong freq. in your tune for your idle valve.


didn't read thread.
Quote:
Originally Posted by Savington View Post
Didn't finish reading OP, didn't watch video or read thread, agree with above.
I third that.
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Old 07-24-2012, 07:50 PM   #10
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Agreed on the idle control valve, but it may not be due to bad tune. My car did it bone stock, it's just that it was way more noticable once I had the turbo hardware installed (some kind of resonance in the intake piping?).

--Ian
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