Notes for vehicles with catalytic converter - AH49.10-P-1000-01A
ENGINE ALL Vehicles with catalytic converters
Ignition misfiring
In the event of ignition misfiring the CATs are endangered because the fuel-air mixture is realized in a hot CAT. If ignition misfiring increases, the engine may only be briefly operated at low load. The damage cause must be immediately rectified. In cases of doubt once the damage to the ignition system has been rectified, the CATs must be inspected for signs of thermal damage.
Checking catalytic converter system for thermal damage
In the event of thermal overload the CAT will be damaged. This can be checked by visual inspection of the removed exhaust system. Performance complaints after faulty engine operation are indications of thermal overloading of the CAT. Residue from the melted CAT will clog up the exhaust pipe.
Fuel additives
These are to be rejected for CAT vehicles. Care must be taken to ensure that only the specified fuel grade is used.
Using leaded fuel
If leaded fuel is used by mistake, the function of the lambda control has to be checked. If the sensor is damaged then it has to be changed. If the emission level is exceeded, then the complete catalytic converter system is to be replaced.
Engine oils
Vehicles equipped with a CAT are subject to the same oil recommendations (approved products, oil change intervals etc.) as for vehicles without a CAT.
Odor nuisance
Deposits of sulfur components from the fuel in the CAT can result in the formation of hydrogen sulfide. Even small concentrations of hydrogen sulfide will present a strong odor nuisance, but it is not a health hazard.
Fire hazard (parking off-road)
The CATs are thermally insulated, to guarantee effective exhaust treatment under all operating conditions. Therefore, when the engine operates correctly temperatures are not any higher than for conventional muffler systems. Increased temperatures only occur when (e.g. through faults in the ignition or injection system) an unburned fuel-air mixture enters the CAT.