How to Bypass Throttle Position Sensor: A Comprehensive Guide

Bypassing the throttle position sensor (TPS) can provide a slight power gain, particularly in the bottom end, but it requires a thorough understanding of the throttle body components and their functions. This comprehensive guide will walk you through the process of bypassing the TPS, including the necessary tools, techniques, and precautions to ensure the safe and effective modification of your engine.

Understanding the Throttle Body Components

The throttle body is the component responsible for controlling the airflow into the engine, and it consists of several critical parts that must be understood before attempting to bypass the TPS.

1. Throttle Position Sensor (TPS): The TPS is a crucial sensor that measures the position of the throttle plate and provides this information to the engine control unit (ECU). It is responsible for ensuring the correct fuel-air mixture is delivered to the engine.

2. Throttle Position Sensor Adjustment Screw (Red Knob): This screw is used to adjust the TPS, allowing you to calibrate the sensor to the correct position.

3. Throttle Stop Screw (Yellow Knob): The throttle stop screw is used to set the minimum throttle position, ensuring the engine idles correctly.

4. Throttle Plate: The throttle plate is the component that opens and closes to control the airflow into the engine.

Bypassing the Throttle Position Sensor

To bypass the TPS, you have two options: using a pre-made TPS bypass unit or creating your own custom bypass.

Using a TPS Bypass Unit

1. Sparks Racing TPS Bypass Unit: The Sparks Racing TPS bypass unit is a popular choice for bypassing the TPS. It provides a slight power gain, particularly in the bottom end, by eliminating the TPS signal.

2. Specifications: The Sparks Racing TPS bypass unit is designed to be compatible with a wide range of engines and throttle bodies. It typically measures around 2 inches in length and 1 inch in diameter.

3. Installation: The Sparks Racing TPS bypass unit is easy to install, requiring only the removal of the existing TPS and the connection of the bypass unit in its place.
4. Cost: The Sparks Racing TPS bypass unit typically costs between $50 and $100, depending on the specific model and your location.

Creating a Custom TPS Bypass

1. Wiring Diagram: To create your own TPS bypass, you’ll need to refer to a wiring diagram for your specific engine and throttle body. This will help you identify the correct wires to connect to bypass the TPS signal.

2. Necessary Components: You’ll need the following components to create a custom TPS bypass:

3. Jumper wires
4. Electrical tape or heat shrink tubing

5. Multimeter or voltage tester

6. Bypass Procedure:

7. Locate the TPS wiring harness and identify the signal wire, ground wire, and power wire.
8. Disconnect the TPS wiring harness from the throttle body.
9. Connect the signal wire to the power wire using a jumper wire, effectively bypassing the TPS.
10. Secure the connections with electrical tape or heat shrink tubing to prevent any short circuits.
11. Reconnect the wiring harness to the throttle body.

It’s important to note that while bypassing the TPS can provide a slight power gain, it is not recommended to do so to compensate for fueling changes due to modifications like exhaust or muffler changes. Doing so may not provide enough gas for the modified airflow, leading to potential engine damage or poor performance.

Resetting the TPS Value

If you need to reset the TPS value back to the manufacturer’s specifications, you can use a TPS tuning harness, which is available for purchase online. This harness allows you to easily adjust the TPS without having to remove the throttle body.

Measuring Engine RPM

To find the RPM on your machine, you can use various tools, such as:

1. LCD Automotive Multimeter with Tachometer Kit: These multimeters are equipped with a tachometer function, allowing you to easily measure the engine’s RPM.
2. Tachometer Hour Meter: This standalone device is designed to measure and display the engine’s RPM.
3. Smartphone Apps: There are several smartphone apps available that can function as RPM gauges, using the device’s microphone to detect the engine’s sound and calculate the RPM.

Precautions and Considerations

While bypassing the TPS can provide a slight power gain, it is important to note that it is not recommended to override the TPS, as it is a crucial sensor for proper engine operation. If the TPS needs adjustment, it may be necessary to replace it, as adjusting it is not recommended by the manufacturer.

Overriding the TPS can lead to issues with the fuel-air mixture, potentially causing engine damage or poor performance. It is crucial to ensure that the engine receives the correct fuel-air mixture to avoid these problems.

Conclusion

Bypassing the throttle position sensor can be a complex task, but with the right knowledge and tools, it can be done safely and effectively. This comprehensive guide has provided you with the necessary information to understand the throttle body components, the process of bypassing the TPS, and the precautions to take to ensure the safe and successful modification of your engine.

Remember, it is always important to consult with a professional mechanic or the manufacturer’s recommendations before attempting any engine modifications to ensure the safety and longevity of your vehicle.

References:
– How to Bypass the Throttle Position Sensor (TPS) – YouTube
– TPPS Bypass – YFZ Central
– How to Adjust Throttle Position Sensor (TPS) – YouTube
– Bypassing the Throttle Postion Sensor – Hardcore Sledder
– Bypassing the Throttle Position Sensor – The Diesel Page Forums