Knocking sound...what the heck is it?
Thread Starter
On The Tree
Joined: Jan 2002
Posts: 148
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From: Dallas area
Knocking sound...what the heck is it? My friend owns a '99 LS1 M6 and at WOT, he hears a rattling noise (like a
metal plate or rod vibrating against solid metal) in what could be the engine
compartment or the dash. We both listened to it carefully but it's really hard to tell...sounds more like the dash to me but just not certain. It's not the same pinging sound that my car made when I had knock retard issues, so I don't think it's that...nor does it sound like the lifter issue my car had. This also happens when it's being revved in neutral. The car runs great (outran my SS when my car was stock) and revs and drives perfectly smooth. It's a lower pitch sound. I wouldn't call it a tap, more like a knock. Does anyone have any suggestions on what this might be? Anything in the dash that might do this? Could this be the injector noise that I've read people talking about?
metal plate or rod vibrating against solid metal) in what could be the engine
compartment or the dash. We both listened to it carefully but it's really hard to tell...sounds more like the dash to me but just not certain. It's not the same pinging sound that my car made when I had knock retard issues, so I don't think it's that...nor does it sound like the lifter issue my car had. This also happens when it's being revved in neutral. The car runs great (outran my SS when my car was stock) and revs and drives perfectly smooth. It's a lower pitch sound. I wouldn't call it a tap, more like a knock. Does anyone have any suggestions on what this might be? Anything in the dash that might do this? Could this be the injector noise that I've read people talking about?
Re: Knocking sound...what the heck is it? i had a rod knock and it was hard to decide. it didnt sound like a "normal" rod knock to me. almost dounded like it was on top of motor but....
either that or push rod.
either that or push rod.
Thread Starter
On The Tree
Joined: Jan 2002
Posts: 148
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From: Dallas area
Re: Knocking sound...what the heck is it? Not sure what you mean by "rod knock"...can you elaborate on that? Also...since the motor seems to be running great, a pushrod problem didn't seem likely to me. What makes you say pushrod?
Thread Starter
On The Tree
Joined: Jan 2002
Posts: 148
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From: Dallas area
Re: Knocking sound...what the heck is it? [quote]Originally posted by Holes02:
<strong>Sounds like the motor is pinging? Or detonating?
Does it do it with higher octane gas too?</strong><hr></blockquote>
Well...my LS1 experience is limited to my car. When my car was making a funny knocking noise, I took it to FAStech and they immediately called it pinging and said I was getting knock retard because of it. This sounds different from that...like a deeper sound, as if it were something big making the noise. Also when mine was pinging, since I had KR I of course could feel the motor drop off up top. His keeps pulling all the way through, like it should. It only makes the noise above about 5000 RPMs though...
Haven't tried higher octane gas yet, I'll have him get some today. Is it possible to have knock without getting knock retard?
<strong>Sounds like the motor is pinging? Or detonating?
Does it do it with higher octane gas too?</strong><hr></blockquote>
Well...my LS1 experience is limited to my car. When my car was making a funny knocking noise, I took it to FAStech and they immediately called it pinging and said I was getting knock retard because of it. This sounds different from that...like a deeper sound, as if it were something big making the noise. Also when mine was pinging, since I had KR I of course could feel the motor drop off up top. His keeps pulling all the way through, like it should. It only makes the noise above about 5000 RPMs though...
Haven't tried higher octane gas yet, I'll have him get some today. Is it possible to have knock without getting knock retard?
TECH Apprentice
Joined: Dec 2001
Posts: 357
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From: Whitby Ont Canada
Re: Knocking sound...what the heck is it? By any chance has there been any exhaust mods or work done, almost sounds like the exhaust is touching the frame at WOT. I just put at set of headers on my truck and had the same problem. Everything looked good for clearance but with some torque the clamp at my collector was touching the frame ever so slightly, enough to hear a slight rumble(or knock)in the cabin.
Thread Starter
On The Tree
Joined: Jan 2002
Posts: 148
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From: Dallas area
Re: Knocking sound...what the heck is it? It's still got stock exhaust, but that could be it! Definitely a sound that the exhaust could make, i didn't think of it because it is stock but you never know. I'll check that out, thanks!
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Thread Starter
On The Tree
Joined: Jan 2002
Posts: 148
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From: Dallas area
Re: Knocking sound...what the heck is it? Found it and fixed it! The throttle cable was tapping the cowl under WOT. I was about to zip tie it down but then noticed the little metal clip on the right side of the engine, which I assume is normally used to hold this cable in place. Snapped it in there, and voila <img src="gr_stretch.gif" border="0">
I'm a big time techie now... <img src="gr_images/icons/wink.gif" border="0">
I'm a big time techie now... <img src="gr_images/icons/wink.gif" border="0">
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