G35 Coupe V35 2003 - 07 Discussion about the 1st Generation V35 G35 Coupe

engine makes wierd screeching noise

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Old Sep 13, 2010 | 11:44 AM
  #16  
gary c's Avatar
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No that sound isn't your belts since the engine isn't running. If you have an aftermarket alarm disconnect it and see if that's where the noise comes from.
This is major freaky and something none of us have heard before to my knowledge....
Gary
 
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Old Sep 13, 2010 | 03:20 PM
  #17  
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Fuel pump while turning on and off???? Weird that it happens that late after it's off?????
 
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Old Sep 13, 2010 | 03:22 PM
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Well the ECU stays on for ~30 seconds after you shut the engine down so that's why I think this is an electrical issue. The noise right after the engine shuts off sounds eerily similar to what I heard coming from ECU/grounding noise on my home made knock sensor monitoring headphones. That last noise is just nuts... but it really sounds related and may be coming from some aftermarket component like an alarm siren. Perhaps a poor ground on the alarm brain amplifying noises from the ECU.
 
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Old Sep 13, 2010 | 03:33 PM
  #19  
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Originally Posted by djamps
Well the ECU stays on for ~30 seconds after you shut the engine down so that's why I think this is an electrical issue. The noise right after the engine shuts off sounds eerily similar to what I heard coming from ECU/grounding noise on my home made knock sensor monitoring headphones. That last noise is just nuts... but it really sounds related and may be coming from some aftermarket component like an alarm siren. Perhaps a poor ground on the alarm brain amplifying noises from the ECU.
Home made knock sensor, that's awesome. Wanna slap me one together??
 
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Old Sep 13, 2010 | 04:07 PM
  #20  
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http://www.uprev.com/documentation/K...n%20Device.pdf



But seriously, that first noise right after shutoff is exactly what I hear in the headphones the entire 30 seconds after shutting it down...the ECU grounding is particularly noisy.
 
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Old Sep 13, 2010 | 04:54 PM
  #21  
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no after market alarm system....the noise as soon as the car turns off (from what i can hear) is from the intake...i really think its a loose hose...do u guys think i should go back to stock intake and take my plenum out? only mods i have
 
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Old Sep 13, 2010 | 05:03 PM
  #22  
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In that case I would focus on the throttle body. That sounds could be the stepper motor (that moves the throttle plate) going bad. It doesn't power off until about 30 seconds after you shut off.
 
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Old Sep 13, 2010 | 06:22 PM
  #23  
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Did you buy the car used?

Maybe the previous owner put one of those stupid turbonator things in the intake, or some sort of similar spinning type turbonator, and it's spinning down in the intake tract once you shut the car off.

If I were you, I'd start the car up with the hood open, and then go stand in front of the car and lean over the engine bay... then have someone else shut off the car and try to see if you can isolate the location of where the noise is coming from.
 
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Old Sep 13, 2010 | 07:03 PM
  #24  
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LMAO! If someone played that sound I would never guess it was coming from a car. I am curious to know what it turns out to be...
 
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Old Sep 13, 2010 | 10:12 PM
  #25  
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Omg I have never,ever heard a car make a noise even similar to that...
In all seriousness,it's somewhat reed-like as if a bad clarinet player was under the car.
Have you checked for seagulls trapped in the core support?ok sorry that's no help..
It really does sound as if pressure has been built up and finally has a chance to escape after the engine is cut off,maybe throttle blades,some thing like that...not really sure what could do that running then when shut off,
I know I speak for all when I say you've Gotta let us know wth that noise is when you get it figured out...Fish
 
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Old Sep 13, 2010 | 10:20 PM
  #26  
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Try some of these mod's lol
 
Attached Thumbnails engine makes wierd screeching noise-ghost.jpg  
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Old Sep 14, 2010 | 06:12 PM
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me and my mechanic friend got together and he said hes just flustered....we cant locate the sound it seems to be moving throughout the engine(throttle body)....hesaid it could be the time chain....??? i plan on putting the stock intake on and maybe opening up the plenum to so if i fudged up somewhere installing a spacer this weekend....the car runs fine,drives fine, ac works, radio works...everyone i take it to says they have never heard anything like it....maybe something got stuck underneath it??? idk i have absolutly no idea
 
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Old Sep 14, 2010 | 06:43 PM
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Sammy, please don't tell us you left the instruction sheet inside your plenum?
Gary
 
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Old Sep 14, 2010 | 07:02 PM
  #29  
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Originally Posted by gary c
Sammy, please don't tell us you left the instruction sheet inside your plenum?
Gary
 
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Old Sep 14, 2010 | 07:48 PM
  #30  
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Wow,don't tell anyone if that happened...
 
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