In this tech article I will cover getting our late model rubber bumper MGs through the Smog Test.

First of all, a really critical component on these MGs is the catalytic converter. To check that the ceramic material is still inside the converter, take a small wrench and gently tap the outside of the converter, if you get a hollow ringing noise, then the ceramic is no longer inside the converter. An empty converter is 0% effective on tailpipe emissions.

Next, the smog pump is a very important component. To check it is very simple, just remove the hose from the air injection rail at the cylinder head and with the engine running, put your thumb over the pump outlet hose and make sure you have good air pressure from the pump. When I was performing smog checks at European Sports Cars, I would check many an MG that had the smog pump turning but being that it was worn out had no air pressure.

Always check to make sure there are no carbon deposits blocking the air injection rail and injection ports inside the cylinder head.

Whenever you fit a new catalytic converter, do make sure that the carburetion is 100% correct, an over rich mixture will soon burn out a new converter.

Paul Lewis