My brother has a problem with his car.....It is the cat converters. The car is an N/A. He recently got pulled over for too loud of an exhaust. He got the cats put back on with no air pump supplying the second cat. I advised against this and said it takes a half of an hour to plum the split air pipe and put the air pump back on. Now the manifold and downpipe glow red hot. I say it is from the air pump and split air pipe not being on the car. The mechanic says that the exhaust is too restrictive and is running overly rich. I agree the car is running rich but would the manifold and downpipe glow red hot from the split air and air pump not being on?

 

The airpump needs to be on it you have catalytic converters on the car.

The aripump WITH the ACV needs to be on the car if you have catalytic converters on the car.

It wouldn't hurt to also have the split air pipe on also.

The airpump feeds the ACV which in turn feeds fresh air to the EXAUST PORTS (you know, those two large holles prior to the exaust manifold) and from the exaust ports then on to the catalytic converters.

The catalytic converters are probably clogged up in my humble opinion. Just a guess. Never done it myself.