Hi all:
my car is making this rattling noise below the center console and it sounds like thud-thud-thud-thud-thud. I want to eliminate the possibility of engine knocking. I really hope it is a loose screw on the heat shield of my exhaust.
this noise does not happen all the time and if it does, I can hear it at all ranges of EGT, from 500c to 700c and from 3000 to 6000rpm. The noise is louder if I slammed on the gas pedal harder. Performance wise, I don't feel any power loss or see any SES light.

I checked my exhaust heat shields last weekend...they are all tight and the only thing that I can think off is the y-pipe hanger which I didnt attach it to the car. (but I bent it and made sure it does not contact the car during driving.)

Does engine knocking only happen when the car is running lean? I hit 850c two time but I dont remember that I heard any noise like this.


thx in advance...

 

well uhmmmm


engine knock would come from the engine, if it comes from under your car, and your sure of that...its not engine knock..heheh

what type of gas are you using? do you know if your leaning out for sure? 850C is still safe for the motor but thats definetely on the lean side.
i can throw my scanner on it and figure something out.

 

n/m

 

It's probably your y-pipe banging against the chassis. The hanger limits the amount of lateral deflection in your exhaust system (as well as holding it up). Without the hanger attached there is probably so much flexibility that the pipe is contacting the chassis at times.

 

thx Matthel.....you remembered the last time I think I got a loose timing chain and turned out it was just a loose bolt? Here I am again.....

the sound is coming from right below the shift console....and unlike what others told me: pinging, it comes in a fast and rhythmic tapping.

I use chveron 91 all the time and I did not feel any power loss or "pinging" when I hit 850c.

btw, have you heard anyone here got busted with a test pipe on their car? I hope my stock appearance will fool the cops...but can they find out with the sound and the smell?

oh~ Can I drop by during the weekend after Christmas?? will u be in South city?



I remembered before I bent that thing....it was banging the body everytime I shift...it was so damn loud and scared a little kid one time. I was thinking that when I floor the pedal, the engine moves a bit and that either stretches or compresses the pipe.

thx for your help




SeaMax : I had the wrap since day one....so I couldnt compare to one without the wrap. I wrapped it because I want to keep my EGT reading consistent.