sghokie

I just bought this 01 boxster, 67k miles on it. It has an issue in the exaust. While idling you can hear the exhaust popping as if popcorn was inside the system. The popping continues for about 10 minutes or so after the car is turned off also.
The car runs great.
I don't have any CEL on.
I assume that the CATs are on their way out.
I put in new plugs the other day, the old plugs looked fine, no fouling and appeared that the cylinders are functioning properly.

Any ideas?

Dave H.

heat expansion/contraction of the exhaust parts.

sghokie

Do they all do this even while running?
I have had a lot of cars over the years, sure they all tick a little bit when you shut them off, but none of them ticked as loud as this one.

fivepointnine

yes, all Boxsters do it, you should hear it after a hard run!

Macster

A hot engine will tick (maybe this could be classified as a popping sound) after being shut off as the hot parts cool and shrink and move a bit.

With the engine running I do not think I've ever hear it tick as generally the heat gradients are not severe enough to cause the parts to shrink and make noise.

A popping noise at the exhaust with no other abnormal engine symptoms, no CEL and with the old plugs looking fine I would have to attribute to a marginal (bad?) muffler.

The warm-up converters are located close to the heads and are checked for proper operation by the DME and the #2 O2 sensors. There is a larger converter (one on each bank) that is not checked/monitored. From this point downstream to the exhaust outlet is where the popping noise I suspect is coming from.

You'll probably need to get the car making the noise and get it in the air and have a pro give a listen.

Sincerely,

Macster.

Silver986

+1 same thing on my car almost everyday. I like ringing it out.

sghokie

I might swing it down to my exhaust shop guy. He has done it all I am sure he would know what is up with it. I am not really that worried about the popping.