Sep 29, 2025

The emissions control system in your Ford converts harmful chemicals produced by combustion into less toxic ones, thereby reducing pollution. As your Ford dealer, we want to tell you some signs that you need to visit us for Ford emission control maintenance.

Black Exhaust Smoke

A fuel-rich engine mixture can cause black exhaust smoke, but it’s also produced by a damaged catalytic converter. The converter is a crucial part of the emissions control system, as it’s responsible for converting engine gases. It does this using crushing pressure, chemical reactions, and intense heat. Once the conversion is complete, the now harmless gases pass through the exhaust system to exit from the tailpipe.

Converters are very robust systems with a lifespan of over eight years, but they can wear out or get damaged. If the converter isn’t working correctly, dangerous gases like hydrogen sulfide and carbon monoxide won’t be converted, and together with unburnt fuel residue, they’ll form a toxic black cloud. We’ll examine the converter and repair or replace it to fix this issue.

Rattling Noises

Strange rattling noises under your vehicle could mean the converter is damaged. The converter has a honeycomb interior structure to provide a large surface area for gas conversion. Large quantities of hot, unburnt fuel dumped into the converter by a fuel-rich engine can raise the converter’s interior temperature high enough to create cracks in the honeycomb.

The heat and pressure inside the converter will cause any cracks to expand, and parts of the honeycomb will break off. These broken sections fall to the floor of the converter and will rattle around as you drive. A damaged honeycomb also reduces the converter’s ability to change harmful gases and creates additional problems. A damaged honeycomb can’t be repaired, but we’ll replace the converter and correct the fuel-rich engine mixture.

Blocked Converter

Carbon is a byproduct of the conversion process, and over time, it can build up inside the converter and block the exit to the rest of the exhaust system. If the exit is blocked, converted gases will flow back into the engine. This raises the pressure inside the engine and can even cause it to shut down.

A strong fuel smell will float into the cabin, and you may experience misfiring or stalling due to the increased pressure. In addition, fuel consumption will rise as the engine has to work harder to try to overcome these problems. We clear any blockages, and the converter will work normally again.

Emission control problems can also cause major engine damage, so they need to be fixed ASAP. Contact our service department at Bob Maxey Ford (Detroit) in Detroit, MI.