Has your car failed its Warrant of Fitness for exhaust emissions?Car exhaust emission repairs in Hamilton NZ

When petrol is burnt inside your car’s engine, emissions are released from the exhaust pipe. To reduce emissions and comply with standards, devices such as catalytic converters are used to reduce these emissions to an acceptable level.

Problems with your car’s engine or exhaust system can lead to increased emissions. As well as doing greater harm to the environment, excess emissions are often linked to higher fuel consumption, lower engine power and can point to a serious problem in your engine.

When you bring your car in for a Warrant of Fitness, the inspector will perform an emissions test. This will involve the inspectors examining the tailpipe for visible smoke under various engine RPMs and operating conditions. If exhaust smoke is visible, your car may fail its Warrant of Fitness due to excess emissions.

Learn more about exhaust emission requirements in New Zealand


What can cause excessive engine exhaust emissions?

  • Bad fuel injectors – The fuel injectors are responsible for adding the correct amount of fuel to the engine. Problems such as leaking fuel injectors can lead to too much fuel entering the engine, causing an incorrect air/fuel ratio. As a result, incorrectly burnt fuel will leave through your exhaust pipe and lead to increased exhaust emissions and pollution.
    Fuel injector replacement in Hamilton
  • Bad oxygen sensor – The oxygen sensor determines how much oxygen is in exhaust emissions. It then sends this data to your car’s onboard computer where changes are made to fuel injection quantity (duration). A faulty oxygen sensor may send incorrect readings. This can lead to too much or too little fuel being added to the engine.
    Oxygen sensor replacement in Hamilton 
  • Worn spark plugs or ignition coil(s)– Spark plugs and ignition coils both help ignite the air/fuel mixture in your car’s engine. When they begin to fail, they will not ignite the fuel correctly. This can lead to petrol fuel not being fully burnt. This fuel then leaves through your exhaust in the form of excess emissions.
    Spark plug replacement in Hamilton 
  • Damaged catalytic converter – The catalytic converter filters exhaust emissions and removes toxins. This leads to cleaner emissions. Problems with the catalytic converter can result in the emissions not being filtered properly.
  • Defective EVAP system – The evaporative emission control system is used to prevent petrol fumes from escaping through the fuel tank or fuel system. If it is not working correctly, gas / vapor may escape. This can be due to a leaking hose or damaged vent.


At Grimmer Motors, we currently aren’t able to test exhaust emissions. However, we can offer replacement services for damaged or failed parts within your car’s exhaust or emission system.


Book Now