So as most of you may already know I have been getting my Integra back in stock shape so I can pass this damn BAR State Smog test. Anyways, I got home and parked it and I heard this intermittent (like every 4 seconds) snap sound coming from under the car. Like what you would hear as it cools down, that crackling. Only it is like evry four seconds. It goes tink 1234 tink 1234 tink, not a crackling, an individual tink ya know what I mean? Anyone know what this is. Just when I think I've done everything...

 

Cat? Just because it is in stock shape does not mean it will pass, not to be a downer or anything

 

No the cat is in good shape. I had it at the dealer again today for a valve adjustment and the noise was coming the resonator of the exhaust. I guess it has had it's time under my car. Yeah I know stock cars will not always pass, but my car is all back to specs w/a curr. tune up, so is no reason for it to fail. I'll let everyone know how goes it whne I get tested again on 12/1.

 

Does the sound ever go away, like if you drive long enough for the entire exhaust system to warm up fully to normal operating temperature?

If the noise does eventually stop, perhaps it's coming from where two pieces of the exhaust system meet... and there is a very slight difference in expansion rates between two pieces of metal at a pipe connection... it might take a long time before both pieces reach their full temp, and so ending the tink.

That begs the question: does the tink sound also happen when the engine is off and the exhaust system is cooling down? If my conjecture is correct, it won't necessarily tink in reverse, but it could.

So maybe a recently opened pipe connection isn't fully closed?

 

I get a similar sound once it warms up....haven't looked into it yet. Sounds like it's coming from the motor.