EngineWiring We offer an alternative to expensive aftermarket engine management systems. We re-wire your factory engine wiring harness to allow you to install the factory computer and engine wiring harness in your project vehicle. Now you can have the Fuel Injected engine swap of your choice up and running at a fraction of the cost. LS SWAPS: Wiring Harness and Wiring Guide - LS Engine DIY Mar 10, 2015The wiring aspect of any LS swap is undoubtedly the most difficult. Most builders are familiar with fabrication techniques, trouble shooting, and parts swapping to make things work, but electronics rise to a much higher level of complexity.