How to install an EGT?

Installing an Exhaust Gas Temperature (EGT) sensor involves a precise process to ensure accurate readings, typically utilizing either a weld bung or a compression fitting for secure placement in the exhaust system. This installation is crucial for monitoring engine health and tuning performance, providing critical data on exhaust gas temperatures.

How to Install an EGT Sensor?

Installing an EGT (Exhaust Gas Temperature) sensor is a straightforward process when approached systematically, primarily involving drilling a hole and securing the sensor using either a weld bung or a compression fitting.

What is an EGT Sensor and Why Install One?

An EGT sensor measures the temperature of the exhaust gases exiting your engine. This data is vital for:

Engine Tuning: Helps identify if the air-fuel mixture is too lean (high EGT) or too rich (low EGT), preventing engine damage.
Performance Monitoring: Critical for turbocharged or supercharged engines to prevent excessive heat, which can lead to detonation.
Preventative Maintenance: Early detection of potential issues like clogged injectors or misfires.

Choosing Your Installation Method

The two primary methods for installing an EGT sensor are:

Weld Bung Installation: Involves welding a threaded bung into the exhaust pipe, offering a robust and permanent solution.
Compression Fitting Installation: Uses a nut and ferrule system to secure the sensor, often preferred for ease of installation without welding.

Each method has its advantages, and the choice often depends on available tools and desired permanence.

Step-by-Step Installation Guide (Weld Bung Method)

The weld bung method offers superior durability and sealing for your EGT sensor.

1. Gather Your Tools and Materials

Before starting, ensure you have:

EGT sensor kit (sensor, bung)
Drill and manufacturer's recommended drill bit size
Welder (MIG or TIG) and welding safety gear
Measuring tape or ruler
Marker
Eye protection and gloves
Anti-seize compound
Shop vacuum or magnet (for metal shavings)

2. Select the Optimal Location

The placement of your EGT sensor is critical for accurate readings.

Turbocharged Engines:
- Pre-turbo (ideal): Approximately 1-3 inches before the turbocharger inlet. This provides the most accurate and responsive reading of combustion temperatures.
- Cylinder-specific: For ultimate precision, a sensor per cylinder exhaust runner, typically 1-2 inches from the exhaust port.
Naturally Aspirated Engines:
- Typically placed in the header collector, 6-10 inches from the cylinder head, or in a single exhaust runner.

Important Considerations for Placement:

Ensure enough clearance for the sensor body and wiring.
Avoid areas with excessive vibration.
The sensor tip should be in the center of the exhaust flow.

3. Prepare and Drill the Hole

Mark the Spot: Once you've chosen your location, mark the center of where the bung will be installed.
Drill the Hole: Using the manufacturer's recommended drill bit size, carefully drill a pilot hole, then expand it to the correct diameter for your weld bung. Ensure the hole is clean and free of burrs. Use a shop vacuum or magnet to remove any metal shavings to prevent them from entering the exhaust system.

4. Weld the Bung into Place

Clean the Area: Thoroughly clean the area around the drilled hole on the exhaust pipe and the bung itself. Remove any rust, paint, or grease.
Position the Bung: Insert the threaded bung into the drilled hole.
Weld Securely: Weld the bung into place around the circumference, ensuring a complete and airtight seal. Allow the weld to cool completely. If you're not experienced with welding, it's highly recommended to seek professional assistance.

5. Install the EGT Sensor

Apply Anti-Seize: Apply a small amount of high-temperature anti-seize compound to the threads of the EGT sensor. This prevents galling and makes future removal easier.
Thread in Sensor: Carefully thread the EGT sensor into the welded bung by hand until it's snug.
Tighten: Using a wrench, gently tighten the sensor. Do not overtighten, as this can damage the sensor or bung. Consult your sensor's instructions for specific torque recommendations.

6. Wire the EGT Sensor

Route Wiring: Carefully route the sensor's wiring away from hot exhaust components, moving parts, and sharp edges. Use zip ties or cable clamps to secure the wiring.
Connect to Gauge/ECU: Connect the sensor's wires to your EGT gauge or engine control unit (ECU) according to the manufacturer's wiring diagram. Pay close attention to polarity.

Step-by-Step Installation Guide (Compression Fitting Method)

This method is simpler as it doesn't require welding.

1. Gather Your Tools and Materials

EGT sensor kit (sensor, compression fitting)
Drill and appropriate drill bit (usually smaller than for weld bungs)
Wrenches
Marker
Eye protection and gloves
Anti-seize compound
Shop vacuum or magnet

2. Select the Optimal Location

Follow the same guidelines as the weld bung method for selecting the best placement.

3. Prepare and Drill the Hole

Mark the Spot: Mark the center for the compression fitting.
Drill the Hole: Drill a hole using the specific drill bit size recommended for your compression fitting. This hole is usually smaller than for a weld bung, as the fitting itself creates the seal. Clean any burrs and metal shavings.

4. Install the Compression Fitting

Assemble Fitting: Slide the compression nut and ferrule (or sleeve) onto the EGT sensor probe, as per the manufacturer's instructions.
Insert into Hole: Insert the end of the EGT sensor probe through the drilled hole in the exhaust pipe.
Secure Fitting: Position the compression fitting body against the exhaust pipe. Thread the compression nut onto the fitting body and hand-tighten.

5. Tighten the Compression Fitting

Final Tightening: Using two wrenches (one to hold the fitting body, one to tighten the nut), slowly and firmly tighten the compression nut. As you tighten, the ferrule will compress around the sensor probe and against the exhaust pipe, creating a seal. Do not overtighten; follow manufacturer specifications.

6. Wire the EGT Sensor

Follow the same wiring instructions as for the weld bung method.

Important Considerations and Tips

Professional Installation: If you're unsure about any step, especially welding, it's always best to consult a professional mechanic or fabricator.
Sensor Calibration: After installation, if your EGT gauge requires it, perform any necessary calibration steps as per the manufacturer's instructions.
Leak Check: After installation, run the engine and check for any exhaust leaks around the sensor or fitting area.
Gauge Compatibility: Ensure your EGT sensor is compatible with your EGT gauge or ECU.
Material Compatibility: EGT sensors typically use K-type thermocouples and are designed for high temperatures, but ensure your specific sensor is rated for your application.

Proper EGT sensor installation provides invaluable data for optimizing engine performance and safeguarding its longevity.