Detecting Exhaust Leak

Are you sure you are hearing an exhaust leak and not engine ping?

 

Hello,

I have a '91 Civic Si, and I believe I have an exhaust leak. At first I
just heard a rattling noise coming from the front part of the car, but
then I recognized that the engine sounded louder like an exhaust leak. I
only hear the rattle and increased noise when trying to accelerate at
low RPM's (maybe around 2500 or lower). I never hear the noise in 1st
gear or when maintaining a constant speed at any RPM. I can always
reproduce the noise by shifting to a higher gear than I normally would
be in at a given speed and giving the gas pedal a good push. I replaced
the pipe from the catalytic converter to the muffler and the muffler
last fall, so I suspect I am looking at from where the manifold meets
the engine block to where the downpipe connected to the header meets the
catalytic converter. I can't see any holes or feel any exhaust escaping.
Does anyone have and ideas or tricks for finding a leak?

Thanks for any help,

Chopface

 

Get someone to hold an old rag over the tailpipe outlet, with the engine
idling. Any leak will be obvious then.