ORS 3RZ-FE / 2RZ-FE Conversion Wiring Harness

(1 customer review)



The 3RZ-FE / 2RZ-FE (2.7L or 2.4L) fuel injection system is entirely different from that of the older Toyotas. This means the 3RZ electronics and circuit will have to be installed in your older vehicle in order to make this engine swap possible. The Off Road Solutions 2RZ/3RZ Conversion Wiring Harness will provide the donor vehicle engine and transmission control circuits in your older vehicle for use with the Toyota engine 3RZ/2RZ computer and components.

Please not that this product is for both the 3RZ-FE and 2RZ-FE engine swap. We will continue our description using the term 3RZ for simplicity.

From the factory, there are 2 primary parts of the OEM 3RZ fuel injection wiring circuit. The first is the engine wiring harness. This is the harness that is primarily attached to the engine. This is sometimes called the injector harness. This harness connects the engine components such as the fuel injectors, ignition coils, air flow meter, etc. to the engine computer (ECU) and the body harness.

The second part of the 3RZ electronic fuel injection circuit is built into the body wiring, along with the rest of the vehicle’s circuits. The body wiring includes the “under-dash” harness, the engine-bay harness (including fuse box), and even the wiring to the rear. About 40% of the 3RZ fuel injection’s wiring circuit is contained in this harness.

We offer our 3RZ Conversion wiring in 2 main formats:

  • Our 3RZ Conversion Adapter Harness is designed for applications that have a used, good-condition, intact engine wire harness from the donor vehicle. Our Conversion Adapter Harness will connect directly to the engine wire harness and the ECU, and works along with the donor engine wire harness to fully complete the engine wiring circuit. Note: The Adapter Format of our conversion harness will not work with “JDM” engine wiring (from Japanese Domestic Market); our Engine wiring format is recommended with JDM donor engines. Once again, the Adapter version requires the use of donor engine wiring that is intact and in good condition; from a North-American-based donor vehicle.
  • Our 3RZ Conversion Engine Wire Harness completely replaces the engine wire harness while also providing the portion of donor engine circuit originally in the body wiring. This harness is a combination of an engine wire harness and an adapter harness and houses 100% of the 3RZ engine circuit in one all-new piece. It is intended for situations when the donor engine wiring is missing, cut or in poor condition. It also works well for JDM import engines since the JDM engine wiring is hard to use in a LHD application.

We also accommodate 2 main recipient vehicle types:

  • Our 22R-E/3VZ-E Vehicle option is for ’85-’95 Truck/4Runner and ’93-’94 T100 vehicles that originally had the 3.0L 3VZ-E engine or the fuel injected 22R-E. This version requires that the original body wiring and fuse box is still in place and will plug directly into the body wiring for a simple install. Very little splicing is required to install this version, it is nearly 100% plug-and-play. The original wiring in your older Toyota will not have to be torn apart, and this version will accommodate your OEM gauges (tachometer will require some additional work during the install), speed sensor, reverse lights, 4×4 system and 4×4 indicator lamp.
  • Our Stand-Alone version is designed for virtually any other vehicle. It works well with carbureted vehicles, other makes, and some race/custom vehicles. This version requires that the vehicle has at least a basic electrical system already in place. This basic system must include: start and ignition switch, charging, fuse/battery and gauge circuits. This will connect to the recipient vehicle through a few simple splices. Note that the Stand-Alone version includes a fuel pump power/control circuit. Note: if your vehicle has no wiring body wiring at all see our Monster Harness.

We offer 2 options regarding the transmission:

  • Manual Transmission: Use this option when using a manual transmission. This includes a case where the donor or recipient vehicle was originally auto and the engine setup will now be manual.
  • Automatic Transmission: Use this option when using a Toyota automatic transmission. This includes a case where the recipient was originally manual but is now being converted to an automatic transmission. Like the engine circuit, the transmission control circuit was originally split between the body and engine wiring. The Adapter format will include the portion of the transmission control circuit originally placed in the body wiring and the Engine Wire Harness format will include all-new transmission connections.

Donor vehicle pricing options are for the Adapter format and depend on the engine harness donor application.

This product is built per order, please allow 2-4 weeks for order completion. This time can vary by season, if completion time is crucial, please contact ORS before ordering.

Notice when ordering: Please include the following information in the “Order Notes” box or a separate email when placing your order. If sending a separate email be sure the name on the order will be obvious.

From Donor Vehicle:

  • VIN, only if 100% certain of engine origin, OR part numbers requested below
  • Toyota ECU part number (8966x-xxxxx)
  • For Adapter Harness version: Toyota engine harness part number (82121-xxxxx), this is found on a paper tag near the ECU connections.
  • Model Year
  • Model
  • 4WD or 2WD
  • Manual or Automatic Transmission

From Your Vehicle:

  • For 3VZ-E/22R-E type: VIN
  • Year Model
  • Model
  • Original Engine
  • Manual or Automatic Transmission (originally)
  • Indicate specific transmission to be used in conversion
  • 4WD or 2WD
  • If 4×4, indicate transfer case application, original to transmission or changed
  • Front suspension type (original or modified)
  • For 89-95 Truck, 90-95 4Runner, Indicate if ADD (Auto-Hub) system is in use
  • Will you be swapping the battery to the left hand side of the engine bay
  • OEM (original-type) tachometer in use?

Core Connectors for 22R-E/3VZ-E recipient type:
For some applications we will need a core connector from your vehicle. If your vehicle is an ’85-’90, we need one core connector. It is found on the 22R-E or 3VZ-E ENGINE harness, near the ECU connectors. There are the 2 connectors that join the engine harness to the body/dash harness, one of these is needed. Once an order is placed, we will send a picture of the connector needed and a label file (for print) that can be used to send the core connector in a USPS Small Flat Rate Box. Cut the connector needed from the ENGINE harness w/ 1-3″ of wire lead. Note: we will fill the core connector w/ new wire terminals.

1 review for ORS 3RZ-FE / 2RZ-FE Conversion Wiring Harness

  1. Zach Ogle

    I cant say thank you enough! Harness came out of the box and looked b-e-a-utiful! It looked extremely professional and was easy to install. A hell of a lot easier then figuring out the wiring on my own. I would recommend this to anyone during a 3RZ conversion. No old school Toyota should be without a 3RZ.

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