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First, the wiring harnesses that I created are not documented on this website. Each combination of 82/83, 84/85 and the donor 87/88 and 89-92 are slightly different.

You need to be familiar with automotive wiring and electrical schematics to complete this project. Also, diagnosing a 7MGTE engine *requires* an understanding of electronics.

• You need to buy the Toyota electrical manual for your year MK2.
  
• Then find yourself a complete MK3 donor car (see parts for details).
  
• Then buy the Toyota electrical and engine repair manual for the year MK3 donor car.
  
  There are some basic concepts in understanding the electronics and wiring for this project. This based on my 85/89 combination.
  
  The main differences are that the the majority of wiring on the MK3 is contained on the engine harness. The MK2 has it in the engine harness, drivers and passenger side fender harnesses and dash cowl wiring.
  
  

  Component	MK2	MK3
  Starter Power	runs from connector near battery	Runs through engine harness
  EFI Power	runs through dash	Comes from engine fuse box (87/88 is different)
  Ignition	Uses a second relay	Built into ignition switch (IGN2)
  Alternator wiring	From fuse box, across radiator support	From fuse box directly to alternator.
  Fuel pump signal	Comes from AFM	Signal originates from ECU
  Tach signal	Wiring goes thru drivers fender	Through engine harness
  AFM	Thru passenger fender	Through engine harness
  Starter Relay	N/A	Not required
  Gauge feeds	Through ECU and various connectors	The M1 connector on the MK3
  Speed sensor	5M ECU dash connector	M1 connector
  AC signal	Cowl dash wire	B1 connector
  FI Resistor	Feed from second IGN relay	IGN2

  
  
  
  

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