Wiring Harnesses and Looms - Toyota Supra Performance This listing is for a brand new 1JZGTE engine harness swap into the 86.5-92 MkIII Supra. These wiring harnesses are built using new wire, new OEM terminals, and new OEM connector housings. Designed for use with the JDM ECU (High impedance injectors, MAP and IAT sensor, no MAF wiring). mk3 wiring harness | eBay Find great deals on eBay for mk3 wiring harness. Shop with confidence. Skip to main content. eBay Logo: 1988 Toyota Supra MK3 #1042 Main Interior Cabin Wire Wiring Harness See more like this. 1988 Toyota Supra MK3 #1042 Rear Interior Cabin Trunk Wire Wiring Harness. Pre-Owned. $69.