When your Geo catalytic converter fails, check to see if the failure was created by the exhaust system emitting too much unburned fuel. If so, you will need to fix the situation. When too much unburned fuel is emitted to the exhaust system, the catalytic converter will fail because of heat stress. The heat is caused by the fuel igniting as it reaches the hot conditions of the catalytic converter core. A rich fuel mixture can be created when the engine's computerized controls (the engine control module) sends the order to release too much fuel into the combustion chamber. The ECM may do that because of failing oxygen and MAP sensors, which the ECM relies upon while regulating the proper oxygen and fuel levels in the combustion chamber. The oxygen sensor, which is located near the exhaust, sends a message to the ECM about the oxygen/fuel mixture that is being emitted. If the sensor fails, or is slow to react, the ECM will by default, send a too-rich fuel mixture by opening up the fuel injectors. If the fuel injectors are failing, a rich mixture can also be created. Repeated misfires can send unburned fuel into the exhaust pipe. If so, check the spark plugs, ignition leads and distributor caps to trace the cause of the misfires. Taking the time to trace the cause of the catalytic converter failure will ensure that your new Geo catalytic converter purchased from our site will run for a long time.