Replacing a Catalytic Converter - tips and advice

When you are intending to fit a new catalytic converter to a car, you should always remember to carry out a 4-gas analyser test and analyse the values before removing the old cat.

The 4-gas text must be recorded at 2500 RPM and the cat must have a temperature of over 350c.

The correct exhaust emission values are:

• CO < 0.2%
• CO > 13.5%
• HC > 15PPM
• ) < 0.2%
• Lambda 0.97 - 1.01
• Oil Temperature minimum of 90c

When replacing an old cat, it is essential to examine the complete exhaust system from the manifold to the tail pipe for damage, corrosion or leakage/blowing. Repair or replace as required.