Manipulation and Bypassing of Emission Control Systems: A Guide for Fleet Managers
Understanding the Why and How
As a fleet manager/owner, you know the importance of maintaining vehicle compliance with emission standards. However, one of the challenges technicians face is dealing with vehicles that have tampered emission control systems. These modifications, often aimed at enhancing performance or cutting costs, can significantly impact air quality and vehicle reliability. Here’s a closer look at why this happens and how it’s done.
Why People Tamper with Emission Systems
- Performance Enhancement
- Increased Horsepower or Torque: Modifications such as removing or altering components like catalytic converters, EGR valves, or DPFs can boost engine performance.
- Cost Reduction
- Expensive Repairs: Replacing or repairing emission components can be costly. Some may bypass or remove components to save money.
- Ignorance
- Lack of Awareness: Some vehicle owners may not understand the environmental and legal implications of tampering with emission systems.
Common Tampering Methods
- Catalytic Converter Removal or Modification
- Reduction in Emissions Control: Removing the catalytic converter or replacing it with a high-flow or test pipe significantly decreases emissions control.
- EGR System Tampering
- Combustion and Emissions: Disconnecting or blocking the EGR valve, or modifying the EGR cooler, affects combustion and increases emissions.
- DPF (Diesel Particulate Filter) Removal or Modification
- Increased Particulate Matter Emissions: For diesel vehicles, this leads to higher particulate matter emissions.
- ECM (Engine Control Module) Tuning
- Altering Engine Parameters: Modifying the ECM's software can impact emissions by changing engine parameters.
- Sensor Manipulation
- Tricking the ECM: Altering or disconnecting sensors like oxygen, MAF, or temperature sensors can make the ECM operate in a less restrictive mode.
Technical Implications of Tampering
- Increased Emissions
- Harmful Pollutants: Tampering leads to higher levels of pollutants, contributing to air pollution and climate change.
- Engine Damage
- Component Dual Purpose: Emission control components also serve to cool exhaust gas or reduce engine knock. Their removal can cause engine damage, overheating, or premature wear.
- Check Engine Light (or MIL)
- Diagnostic Trouble Codes (DTCs): Tampering often triggers DTCs, resulting in a MIL. Ignoring this can hide underlying issues.
- Legal Consequences
- Fines and Penalties: Tampering is illegal in most jurisdictions and can result in substantial fines and other penalties.
Detecting Tampered Emission Systems
As a technician, your role in visual inspections is crucial. Here’s what to look for:
- Missing or Damaged Components: Check for missing or visibly damaged emission components.
- Exhaust System Modifications: Look for signs of welding or other modifications.
- Unusual Exhaust Characteristics: Be aware of unusual noise or smoke.
- Sensor Issues: Look for evidence of sensor tampering or disconnection.
By understanding these tampering methods and their consequences, you can better identify and address these issues, contributing to cleaner air and safer vehicles.
If you need a Clean Truck Check test for CARB compliance, visit our website at
www.sacvalleydieseltesting.com
or call us at 530-650-6646