Weird rattle sound that feels like hammering at low idle

[HondaLuver83]

That might be a good idea! Vibrations, as previously noted, are often hard to diagnose because they can be amplified and sound like they are coming from somewhere else then where they are actually coming from. The part that makes me think it could be the cat is the lack of any evidence of something actually hitting something and the fact that I got a catalyist effeciency below threshold code that I never had before this problem. If memory serves me correctly the car didn't make any noises when I first test drove it after the swap but started making the noises on my way home from my parents place. Maybe I should pull the O2 sensor and put a screw driver into the cat and see if its loose.

You dont need to do all that, just bang on it with a rubber mallet. You will most likely re-create some kind of sound if its the catalytic converter.

 

[bjorkmae]

Well I got the catalyist below effieciency code again tonight. Perhaps tomorrow I will check it out. Too tired and lazt today with work and such.

 

[bjorkmae]

Hey if the cat is bad what would be the drawbacks of just hollowing out the cat and using the anti foul trick on the O2 sensor? I see test pipes but they honestly just look like what a hollowed out cat would look like.

 

[HondaLuver83]

Hey if the cat is bad what would be the drawbacks of just hollowing out the cat and using the anti foul trick on the O2 sensor? I see test pipes but they honestly just look like what a hollowed out cat would look like.

Hollowing out a cat is dangerous, just buy a resonated test pipe and buy an O2 bung fouler so u dont get a CEL.

 

[bjorkmae]

How is a hollowed out cat dangerous? Will it just sound like ***? I can get a universal cat installed for $100 and be legal or for $50 plus shipping for the test pipe pipe the cat almost seams like a better option since it would keep it legal. What power gain, if any, are achieved with the test pipe?

 

[HondaLuver83]

How is a hollowed out cat dangerous? Will it just sound like ***? I can get a universal cat installed for $100 and be legal or for $50 plus shipping for the test pipe pipe the cat almost seams like a better option since it would keep it legal. What power gain, if any, are achieved with the test pipe?

You gain like 3-5hp without a cat. and you exhaust sounds better. You could buy the test pipe and an O2 fouler and no CEL would come on. Ive had mine on for about 2 years without one light.

 

[bjorkmae]

Ok so the test pipe is sounding better. Any reason I can't just weld in a straight piece of pipe to replace the cat and weld an O2 bung into the straight piece of pipe? So how exactly is a hollowed out cat dangerous? I really am curious, not trying to be a jerk I just don't understand thats all. Thanks

 

[bjorkmae]

Ok if the cat is the problem what do you think of this?
http://cgi.ebay.com/ebaymotors/Head...id=p4506.c0.m245&_trkparms=65:12|39:1|72:1171

 

[ryan s]

think about what goes through the cat and what it traps. then consider what the cat is made of.

then think about what happens when you poke around inside it and let all that stuff go into the air and/or your lungs.

dont f with emissions stuff...keep a cat on there...

 

[bjorkmae]

FOUND IT!!! OK so on the driver's side engine mount there is a mount movement limit in place to prevent excessive engine movement if the mount were to break. Well what was happening is the cat would start to plug up as it would heat up and therefore cause the engine to strain harder at idle causing a heavier vibration. This would in turn make the mount continuously hit the limiting bracket. Thats also why I got the catalyst below efficiency code. So to fix the problem I simply replaced the cat with a section of pipe and used the defouler trick to prevent a CEL. The car isn't any louder that I can tell but does have a significant gain in power. And of course the banging noise is gone