JDM Engine Swap Wiring: Tips and Tricks

Jun 10, 2023

JDM Engine Swap Wiring: Tips and Tricks


So, you’ve decided to swap your engine with a JDM one. Good for you! But before you start installing, it's important to know that JDM engines have different wiring from the USDM ones. You'll need to ensure that all the wiring is correctly installed to avoid engine malfunction or even fire. Therefore, we have compiled a list of tips and tricks to guide you through the JDM engine swap wiring process.



Get the Right Wiring Harness



The first step in JDM engine swap wiring is to get the right wiring harness. This could either be an engine harness adapter or a complete wiring harness from a JDM vehicle. It's important to note that the wiring harness should match the model and year of your car and the engine. If you use the wrong one, the sensors might not work, causing a check engine light or even engine failure.




Label the Wires



When wiring the JDM engine swap, it's crucial to label the wires properly. This will ensure that you don't get confused or mix up the wires. Take a picture of the original wiring and label each wire to match the new engine. Be meticulous when labeling wires, especially if the engine has extra sensors, like VTEC or turbo.



Strip and Splice Wires



Before splicing wires, strip all the wires on both ends exposed and twist them together. After you twist the wires, join them using a connector or solder them together. Be cautious if you use quick-splice connectors as they weaken over time and damage the wiring. Don’t forget to use heat shrink tubing to protect the connection and avoid corrosion.



Extend or Shorten Wires



Sometimes the wiring on the JDM engine might be too long or too short to fit your car. When extending wires, use the same color wires and twist them together before splicing. Don't forget to trim the connection and wrap it with electrical tape. When shortening wires, cut them into the length you need, strip both ends, and splice them back together.




Check the Grounds



Grounds are important for the electric system to function correctly. Check to see that all wires that ground to the engine are connected. It's important to clean the ground before you connect the wires to ensure a good contact. A bad ground can cause several problems like weak spark, starter failure, or poor performance.




Swapping a JDM engine is a fantastic upgrade for your car, but it comes with some risks, mainly with the wiring. To ensure that your engine functions correctly, it's essential to get the right wiring harness, label the wires, strip and splice properly, extend or shorten the wires, and check the grounds. Following these tips and tricks will save you time, money, and, more importantly, keep your engine from malfunctioning or failing. Now that you know these tips, go ahead and get started with the JDM engine swap wiring process!