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Strange raspy sound from 3800sc by NetCam
Started on: 06-03-2014 07:07 PM
Replies: 26 (498 views)
Last post by: Darth Fiero on 06-23-2014 03:04 PM
NetCam
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Report this Post06-03-2014 07:07 PM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
While out on the highway yesterday, I opened it up to see how it would run as I haven't had many chances since the install. It was going like mad until I hit about 5,000 or so RPM, then it seemed to lose power a bit. I got off the highway, and then noticed this raspy sound (brap-brap-brap is the only way I can describe it) whenever I get up to about 3,000 RPM, just before shift revs. Has something happened to my supercharger? Engine sounds fine below 3,000 but then sounds like an exhaust leak over that.

[This message has been edited by NetCam (edited 06-08-2014).]

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Purple86GT
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Report this Post06-03-2014 08:44 PM Click Here to See the Profile for Purple86GTClick Here to Email Purple86GTSend a Private Message to Purple86GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
Pinging?? I'm in Mississauge today and I know it was hot as heck all day.. What fuel are ou using?
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NetCam
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Report this Post06-03-2014 08:48 PM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
Using premium gas. Not a pinging, and definitely not a healthy sound. I'm afraid to go over 3K RPM for fear of doing some major damage if it's not already done.
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dobey
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Report this Post06-03-2014 09:30 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Have a video? What exhaust/muffler do you have on the car? Are you sure it's just not how it's supposed to sound, if you haven't driven it that hard yet since the install?
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NetCam
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Report this Post06-03-2014 10:40 PM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'll try to do a video tomorrow. It's never sounded like this before, started immediately after I went WOT on the highway. Strange part was the loss of power as it hit the upper RPM band almost like the SC had cut out.
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Fadingaway
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Report this Post06-04-2014 09:50 AM Click Here to See the Profile for FadingawayClick Here to Email FadingawaySend a Private Message to FadingawayEdit/Delete MessageReply w/QuoteDirect Link to This Post
Wouldn't hurt to take the belt off of JUST the supercharger
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Raydar
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Report this Post06-04-2014 01:41 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
Are you running it through the stock muffler? I've had one to deteriorate to the point that it sounded like an airplane. The inner and outer layers were apparently banging against one another. Or something.
"BRRRAAAP" describes the sound perfectly. Was a real WTF moment when it happened.

If it's making a whole lot of noise, your knock sensor might be picking it up as "knock", and pulling out a bunch of advance.
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NetCam
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Report this Post06-04-2014 06:17 PM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm running a Magnaflow muffler, and it's less than a year old, but you're right, it does sound like a shot muffler, but I can't really see that being the case this early on. I will see if I can get under to have a look just in case, but my jack doesn't do a very good job since I lowered the car. Canadian Tire has a sale starting tomorrow on low profile jacks so I'm hoping to get out there first thing in the morning and grab one.
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NetCam
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Report this Post06-04-2014 07:06 PM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
Quick video of the sound -

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phonedawgz
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Report this Post06-04-2014 07:16 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
The noise that sounds like an exhaust leak?

If so then my guess is an exhaust leak.
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NetCam
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Report this Post06-04-2014 07:20 PM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
Listening to it when I'm not driving it does sound like an exhaust leak. Wondering if a place like Midas would put it up on the hoist and look at it for me.
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Report this Post06-05-2014 12:32 AM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
definitely sound like metal slapping, but more like a wristpin than exhaust.
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hercimer01
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Report this Post06-05-2014 12:36 AM Click Here to See the Profile for hercimer01Send a Private Message to hercimer01Edit/Delete MessageReply w/QuoteDirect Link to This Post
I had a problem like that. It sounded like gravel in the heads around 3,000 rpm when I would tromp on it. Mine turned out to be a loose vacuum hose on the boost line to the fuel pressure regulator. It is actually acting like a rev limiter as it gets starved for fuel.


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[This message has been edited by hercimer01 (edited 06-05-2014).]

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Tony Kania
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Report this Post06-05-2014 01:48 AM Click Here to See the Profile for Tony KaniaSend a Private Message to Tony KaniaEdit/Delete MessageReply w/QuoteDirect Link to This Post
My only reccomendation is the probe around with a stethoscope. That little tool is a staple in my box, and really can help pinpoint many mechanical issues.

Good luck.
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NetCam
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Report this Post06-07-2014 11:07 PM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
Checked all the vacuum hoses and can't seem to find anything loose. Scope won't do me any good, because I can't seem to get it to make any noise in the driveway, even if I rev it up to 3K. Seems it will only do it under load.
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Lou6t4gto
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Report this Post06-08-2014 12:41 AM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
only under a load, POWER BRAKE IT ! that should do it.
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NetCam
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Report this Post06-12-2014 04:25 PM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
The sound is now getting worse and worse, to the point I can hear it at idle. I got it up on a hoist and put a scope on it, and it is definitely something internal. Seems to be coming from the number one cylinder, and could be a spun main bearing or connecting rod related. I guess I'm in the market for a new engine......
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Report this Post06-12-2014 07:43 PM Click Here to See the Profile for NightMare CruiserSend a Private Message to NightMare CruiserEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hows your oil pressure? Do you have a oil pressure gauge??
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NetCam
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Report this Post06-13-2014 12:23 AM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
Actually I did notice the oil pressure was a lot lower than normal. It's always been on the high side, around 400 and today it was probably around 150.

Short video of what it's sounding like now -

[This message has been edited by NetCam (edited 06-13-2014).]

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carbon
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Report this Post06-13-2014 10:37 AM Click Here to See the Profile for carbonSend a Private Message to carbonEdit/Delete MessageReply w/QuoteDirect Link to This Post
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Report this Post06-13-2014 11:02 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
no metal shavings in the oil filter? I think one piston is trying to break loose.....
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Report this Post06-13-2014 02:42 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'd pull the valve covers off and check the play in the rockers and for any bent pushrods or such, too. And a compression test.

No milky oil, or metal shavings in it?
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NetCam
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Report this Post06-13-2014 10:26 PM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm going to take a better look at things on Sunday, but not holding out much hope for this engine. I'll check the oil and look at all the pushrods too.
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LoW_KeY
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Report this Post06-14-2014 12:06 AM Click Here to See the Profile for LoW_KeYSend a Private Message to LoW_KeYEdit/Delete MessageReply w/QuoteDirect Link to This Post
I got issue going on with mine too

not sure if it's valve train related or what... cylinder 5 is giving me hell i want to cry right now. Keep us updated.
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Report this Post06-14-2014 12:49 AM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
Lo Key, check that #5 is getting a signal for the injector to spray. That engine sounds like something is ready to "let go".
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Lou6t4gto
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Report this Post06-22-2014 01:51 PM Click Here to See the Profile for Lou6t4gtoClick Here to Email Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
SO, have you determined exactly WHAT is wrong ??
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Darth Fiero
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Report this Post06-23-2014 03:04 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by NetCam:

Actually I did notice the oil pressure was a lot lower than normal. It's always been on the high side, around 400 and today it was probably around 150.



Sounds like bearing noise to me; and if you have noticed the oil pressure has been dropping from where it normally operates, it probably is.

Were the lower intake gaskets on this engine changed recently (within the last 1000 miles or so)?

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