The Official 4G63 Wiring Thread. Bring It!

[4g63mightymax]

This thread is going to solve all the mysteries of the 4G63 wiring. I've also documented all of my rwd swap 4g63 wiring information on the Hotrodwiki because forum posts can sometimes be a lot to handle.





Here is the 1991-94 4G63 DSM wiring diagram / schematic that I made:



Here is the 1990 4G63 DSM wiring diagram / schematic that I made:



Here is a 2G 4G63 DSM wiring Diagram that Brendon M. Made:



This is the small ECU connector with all the important power wires.

This is the medium ECU connector

This is the large ECU connector

This is the MPI relay connector


This is the C-59 connector. It has some ignition power wires going through it.

This connector goes under the dashboard, and has all the important dash wires going through it for your gauges and switches.

I'm pretty sure these plug into a fuese box under the hood. Though I may be wrong.


This is the boost control solenoid connector.

This is the Mass Airflow Sensor connector.




From left to right. The O2 sensor connector. The 2-wire temperature sensor connector for the ECU. The 1-wire temperature sensor for the gauge cluster. The 2-wire temperature sensor for the electric fan.

This is the coil pack connector. Triangle ones like this are for the 91-94 4G63 DSM's.

This is the power transistor connector. This "rounded" style is for a 91-94 4G63 DSM's.

This is the A/C compressor clutch connector.

This is the knock sensor connector. It has two wires and is gray.

This is the windshield wiper motor connector. It has 4 blue wires going to it.

The connector on the left is the ISC connector, it has 6 wires. The connector on the right is the idle switch connector.

[dumptruck2]

here's the whole harness on the floor


here is the ecu side



here is the engine side



and here is the battery side and lights i think?

[4g63mightymax]

I worked on it for about an hour tonight. This is what I have so far. I am just going to update it as it progresses. (I will also make it bigger, haha)
The coolant temp sensors are slightly confusing in the picture, and a few others, but I'll figure them out, I just need a little longer to work on it.....
Once I have everything labeled, then I can make another part that matches up what each connector actually is.


-Jeremy

[89coltgt]

I will ad that a very useful(required) tool when tackling the wiring is a multimeter. I will have to dig up all of my notes from my wiring and post it up.

[4g63mightymax]

The X's mean it is 1 centralized junction block. Basically, it's one of the fuse / relay boxes under the hood.

The BOLD items are the important ones.

A-01X Taillight Relay
A-02X Headlight Relay
A-03X Radiator Fan Motor Relay
A-04X Pop-Up Motor Relay
A-05X Power Window Relay
A-06X Alternator Relay
A-07X Fog Light Relay
A-08 Dual pressure Switch (A/C)
A-09 Wiper Motor
A-10 Control Wiring Harness and Battery Cable Assembly Combo.
A-11 Auto Cruise Control Vacuum Pump
A-12 Brake Fluid Level Sensor
A-13 Control Wiring Harness and Solenoid Valve Harness Assembly Combo. (whatever that is?)
A-14 Purge Control Solenoid Valve
A-15 Fuel Pressure Solenoid Valve
A-16 EGR Solenoid Valve (California Cars)
A-17X Condenser Fan Motor Relay, High-Low Changeover Relay
A-18X Condenser Fan Motor Relay
A-19X Magnetic Clutch Relay (for the A/C compressor)
A-20X Condenser
A-21 Air Conditioning Relay Box
A-22 Air Conditioning Relay Box
A-23 ABS Front Speed Sensor (Driver Side)
A-24 Washer Motor
A-25 Pop-up Headlight Motor (Driver Side)
A-26 Front Combination Light (Driver Side)
A-27 Front Combination Light (Driver Side)
A-28 Headlight (Driver Side)
A-29 Horn (Driver Side)
A-30 Horn (Driver Side)
A-31 Fog Light (Driver Side)
A-32 Condenser Fan Motor
A-33 Front Turn Signal Light (Driver Side)
A-34 Hydraulic Unit (ABS maybe?)
A-35 Hydraulic Unit (ABS maybe?)
A-36 Mass Air Flow Sensor (MAF)
A-37 Automatic Transmission Fluid Temperature Sensor
A-38 Kickdown Servo Switch
A-39 Pulse Genrator (For Automatics)
A-40 Radiator Fan
A-41 Front Turn Signal Light (Passenger Side)
A-42 Radiator Water Level Switch
A-43 Fog Light (Passenger Side)
A-44 Horn (Passenger Side)
A-45 Horn (Passenger Side)
A-46 Headlight (Passenger Side)
A-47 Front Combination Light (Passenger Side)
A-48 Front Combination Light (Passenger Side)
A-49 Pop-up Headlight Motor (Passenger Side)
A-50 Hood Switch
A-51 Wastegate Solenoid Valve
A-52 Control Wiring Harness and Engine Compartment Wiring Harness Combination. (whatever that is?)
A-53 Control Wiring Harness and Engine Compartment Wiring Harness Combination. (whatever that is?)
A-54 ABS Front Speed Sensor (Passenger Side)
A-55 Fuel Pump Check Connector
A-56 Noise Condenser
A-57 Defogger Relay
A-58 Fuel Injector Resistor
A-59 Engine Speed Adjust Connector
A-60 Ignition Timing Adjust Connector


B-01 Injector number 4
B-02 Throttle Position Sensor
B-03 ?
B-04 Idle Speed Control Actuator
B-05 Idle Switch
B-06 Injector Number 3
B-07 Knock Sensor
B-08 EGR Temp Sensor (California Cars)
B-09 Injector Number 2
B-10 Injector Number 1
B-11 ?
B-12 ?
B-13 ?
B-14 Ignition Coil
B-15 Power Transistor
B-16 Magnetic Clutch (A/C Compressor)
B-17 Power Steering Oil Pressure Switch
B-18 Alternator
B-19 Alternator
B-20 Engine Compartment wiring harness and engine wiring harness combination? (thats what it says!)
B-21 Oil Pressure Switch
B-22 Oil Pressure Sender (For The Gauges)
B-23 Back Up Light Switch (w/ Manual Transmissions)
B-24 4-Speed Automatic Trans Control Solenoid Valve
B-25 Inhibitor Switch
B-26 Oxygen O2 Sensor
B-27 Starter
B-28 Starter
B-29 Engine Coolant Temperature Sender (For The Gauges)
B-30 Engine Coolant Temperature Sensor
B-31 Engine Coolant Temperature Switch
B-32 Crank Angle Sensor (CAS)

[4g63mightymax]

#1 cylinder (front cylinder)
Yellow with a Blue Stripe & Black with a Yellow Stripe

#2 cylinder
Yellow with a Black Stripe & Black with a Blue Stripe

#3 cylinder
Black with a White Stripe & Light Green

#4 cylinder (rear cylinder)
Black with a Red Stripe & Light Green with a White Stripe

[4g63mightymax]

I have said this a million times to everybody that does this swap, but I will say it again. On these engines, Mitsubishi decided to use the same square connector in several different locations. The fuel injector resistor plug might plug into the ISC motor and vice versa. The engine will run with these plugs swapped, but VERY crappy. (not that I would be stupid enough to mix these wires up..... )

So,
On a 1991 4G63 Engine:

The MAF wires should be: (Connector A-36)
Green w/ White stripe
Green w/ Blue Stripe
Red
Green w/ Red Stripe
Green w/ Black Stripe
Green w/ Yellow Stripe
Green w/ Orange Stripe

The Fuel Injector Resistor wires should be: (Connector A-58 )
Black w/ Yellow Stripe
Black w/ Blue Stripe
Black w/ White Stripe
Black w/ Red Stripe
Red

The ISC Motor wires should be: (Connector B-04)
Blue
Red
Yellow
Black
Red
White

-Jeremy

[4g63mightymax]

If you are wondering what all the sensors are on the 4G63 thermostat housing, here is your answer. The wiring colors mentioned are for a 91 model 4G63.

On the thermostat housing:

The Upper Most 2 pin sensor:
1 Black wire with Green Stripe (goes to pin 7 at ECU)
1 Green with Yellow Stripe (goes to a A/C switch)
This is the coolant temperature switch that turns on the fan(s). I don't remember if it controls just the A/C condensor fan or both, but it is definitely the sensor (switch) for the fans.

The Middle 2 pin sensor:
Green with a Black Stripe (Sensor Ground / Pin 24 at ECU)
Yellow with Green Stripe (Pin 20 at ECU)
This is the coolant temperature sensor for the ECU. It tells the computer if your engine is hot or cold. It also gives the temperature to your datalogging device (through the ECU ofcourse).

The Lowest One Pin sensor:
Yellow with a Green Stripe (Goes to factory temperature gauge)
This is for the factory temperature gauge. A simple 1 wire connector.

On my truck, I got rid of the upper sensor (for the fan), and ran an aftermarket electric fan with it's own temperature sensor on the radiator. I can set it to turn on at any temperature I would like, and also have it wired to a toggle switch in case of emergencies.

-Jeremy

[4g63mightymax]

The MPI relay distributes power to the 4G63. Without it, your engine is dead in the water. If you wire it wrong, you will have problems like your fuel pump not turning on, ECU not powering up properly, etc. Here is some help.

Unplug the connector from the MPI relay and look straight into the pins at the end of the wiring connector. Make sure the clip that locks the connector into the MPI relay is facing up.
The order of pins are:
123 45
678 910

Pin 8 - Black with a Blue Stripe - Goes to Pin 63 and 66 at the ECU.

Pin 10 - Black with a Red Stripe - Goes to fusible link #1 in the main fuse box of the Eclipse / Talon / Laser. The fusible link #1 is a 20A fed directly off the battery.

Pin 4 - Red wire - Goes to Pin 107 and 102 at the ECU. It also jumps over to Pin 5 on the MPI relay, and sends power to the:
Airflow Sensor
Crankshaft Position(Angle) Sensor (CAS)
Wastegate Solenoid
Idle Speed Control Actuator (ISC)
O2 Sensor
Injector Resistor
Purge Control Solenoid
Fuel Pressure Solenoid
EGR Solenoid (California Models Only)

Pin 5 - See Pin 4 Above

Pin 9 - Black with a Yellow Stripe - Goes to Pin 108 at the ECU and the starter relay. This should ONLY have power when the engine is cranking from the starter.

Pin 6 - Black wire - Grounded

Pin 1 - Empty

Pin 3 - Black with a White Stripe - Ignition power and Pin 110 at the ECU. It also powers the Ignition Coil and Power Transistor

Pin 2 - Black with a Green Stripe - Goes to the Fuel Pump and a test connector. The test connector is used to jump the fuel pump if the MPI relay doesn't turn it on.

Pin 7 - White with a Red Stripe - Pin 56 at the ECU

-Jeremy

[89coltgt]

Hey Jeremy, has anyone done the 4g63 swap in an efi truck? I found a 95 MM that I may pick up and swap everything into, it is alot cleaner/lower miles, but the rad support needs to be replaced.

[4g63mightymax]

My first 4G63 swap was a 1990 efi (Electronic Fuel Injection) truck. Also dumptruck's started as a injected truck. It is slightly more complicated than the carbureted models, but still very doable.
Does that mean that you would junk your current truck and start fresh?
-Jeremy

[89coltgt]

Does that mean that you would junk your current truck and start fresh?
-Jeremy

I would part out what I don't need and pull everything off of it, scrap the rest. After doing the first truck, there is alot of things I would like to do differently, and my chassis is very rusty and I plan to put a real suspension under the rear, so I would like to have a nice chassis to start with. We will see, the 95 mm that I am looking at has a bent rad support so that needs to be replaced, otherwise it is clean and straight.

[rlowz4g63mini]

ok if i got a none tubo harness can i plug up a turbo mafc and it work?also i got the harness spread out on the floor and can i cut off all the wires that go to the dash plugs?

[89coltgt]

ok if i got a none tubo harness can i plug up a turbo mafc and it work?also i got the harness spread out on the floor and can i cut off all the wires that go to the dash plugs?

No, the maf will not plug into the nt harness. As far as the dash plugs go, I always like to cut the dash side off of the donor car and wire into the plugs, makes it look more oem

[4g63mightymax]

No, the maf will not plug into the nt harness. As far as the dash plugs go, I always like to cut the dash side off of the donor car and wire into the plugs, makes it look more oem

I agree! It is weird that you type exactly what I am going to say. This is getting creepy. Stay out of my brain!
-Jeremy