Hey man I had that same problem with my cat. I checked the heat shields and couldnt find where the noise was coming from started to get so PO'd. well i ended up jacking my car up and finding the noise was in the cat by tapping on the pipe. I took the exhaus down and a bunch of black crap fell out of the cat and onto my face. it was a bad for me but i found the noise. hope this helps a bit

 

check all heat shields, do you still have a CEL? If you do, pull the code and see what thats about....and did you reset your ECU when you installed the new cat? If not your car prolly doenstl ike that. Any moving onto the rattling....is it metal on metal? Do you have an aftermarkte exhaust system or short shifter? My short shifter rubs against my exhaust at certain RPMs, and that can get annoying, and with my bigger exhaust its hard to get rid of. And you said silence, does he mean resonator? That might have a heat shield about it too, idk. Also check all your hangars to make sure you did break one of those, which would let the exhaust move alot more and possibly vibrate against some part of the undercarriage

 

Thank you everyone for all the input.
The noise comes from the front , where the gears are so doesnt it mean that if its the heat shield, it the front one and not the back one.
I checked the CEL code and it is

P0420 - Catalyst System Efficiency Below Threshold (Bank 1)

I have reset it , hope it doesnt come again.

After installing a new cat, do you have to reset the ECU ? my mechanic didnt reset anything , he just installed the cat and thats it.
Yes it is sort of a metal on metal noise. Sorry im not very technical so dont know what an aftermarket exhaust system or short shifter is. BTW what is a hangar ? Im not sure if he meant resonator when he said silencer.

Could this noise be coming from the left over heat shield ? Last time when the mecanic was installing the cat i noticed that a portion ofheat shield or its covering ... whatever that was wsa still there as he didnt remove it completely. Also ive noticedthat i start getting the noise when the car gets a bit heated , doesnt come at all when i start it ora few minutes after that toowhenthe engine is still cold.

 

So did you get a new Cat ? was the noise coming because of the black crap ? by i just had a new cat.

 

Does it sound like this?

http://youtube.com/watch?v=RjSspd2TfhQ

Thats a vid of my exhaust. Im also getting a strange rattling sound in the front end my exhaust system. I removed the larger heat shield over the cat, but it didnt fix anything. I havent a clue as to what this noise is and its really tickin me off!

 

Although it was a bit tough to figure out the noise from the video, but i guess its exactly the same kind of noise im getting, my mechanic also took off the heat shield which didnt help, even a new cat didnt help

 

Guys , putting away the noise issue , i got the ECL back after around 15 miles after resetting it.

P0420 Catalyst System Low Efficiency

 

Guys, thanks eveyone for their help, noise problem is solved, btu the CEL problem remains, so i haven started a new thread with just the CEL .

Thanks a lot

 

hi guys
i own a honda civic 1.4is 2000 5 door and i recently stared getting the exactly rattling noise i have remover all the heat shields and tried everything it didnt help

its the exactly same noise as shown in this video
http://www.youtube.com/watch?v=RjSspd2TfhQ


please guys help