PDA

View Full Version : weird noises


AJ
12-26-2001, 12:40 PM
allright.. i've talked about this topic one other time.. but here it goes again

1.  When i am slowing down from 2600 rpms or higher, as SOON as i hit 2500 rpms i hear this weird rattling noise which seems to come from in front or right below me.....  (problem #1)

2.  When i'm going fast and revving the car up to 6000 or higher, right when i pass 5500 rpm's i hear the same noise, but form the back of the car instead. (seems like the back of the car anyway)

help if you can!.. (my only idea, is that it is the firewall, and the other metal thing back by my exhaust that are the culprits.. but i figure someone here probably can probably make a better guess.  thanks in advnace!

ca18guy
12-26-2001, 01:13 PM
Probably the heat shields for the exhaust rattling. I've got a similar problem.

AJ
12-26-2001, 01:21 PM
how do we fix them?!.. and why do they rattle only at certaiin rpm's?

ca18guy
12-26-2001, 01:27 PM
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from AJ on 1:21 pm on Dec. 26, 2001
how do we fix them?!.. and why do they rattle only at certaiin rpm's?</td></tr></table><span id='postcolor'>

Fix em by finding the shields along the exhaust and either remove them or retighten them. Why do the rattle at certain rpms? Magic....... or certain rpm's cause more engine shake then others.

AJ
12-26-2001, 01:30 PM
aiight, that sounds about right.. now, will removing them have any adverse effects?.. should have them removed when i gat a catback installed?.. would that be easier?.. &nbsp;or have them replaced, tightened.. etc.. what do you think&gt;

tnord
12-26-2001, 10:21 PM
i would say definitely heat shields, but be careful when you take them off, i've heard of people's carpet melting because of the heat that comes through the floor as a result

my fault on the picture, didn't know it would turn out so #### big

(Edited by tnord at 10:22 pm on Dec. 26, 2001)

gfisch
12-27-2001, 11:26 AM
If they arent broken or in the way of anything, I'd say just leave em on and tighten them. Its not hard. Also check to make sure that it isnt the cat rattling and making the noise. The secondary cat is located just below you. It has mounting brackets to the frame on the end closer to the engine that may have come loose.

As for the rattling at certain RPMs, its because that RPM causes the engine/exhaust system to oscilate at the resonant frequency of that part tahtas rattling. Same effect as a resonator tip on an exhaust system. &nbsp;Too much detail there, but figured id share some stuff from my mech. engineering classes.

Greg

AJ
12-27-2001, 11:07 PM
ahhh that makes sense,, hey, thanks for all your replies,, i'll be getting under my car soon and trying to figure it out <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'>