Wiring a fuel injected vehicle can be overwhelming. The key to letting it not overwhelm you is to focus on a little bit at a time. I have found that this works for almost all major projects. Wiring can be made easy when you break it down to what it is. You are basically just sending power and ground to different areas of the engine to make things work. Since most people that do this engine swap start off with a 90-94 Eclipse engine harness, most of the hard work is already done for you.
The first step is to learn what all of the sensors and stuff does and what actually needs to be hooked up. I will start with the basics and work from there.
Things you need to make it run correctly (based off a 1991-94 Eclipse / Talon / Laser engine harness, 4g63T engine):
1) Throttle Position Sensor (TPS) - 3 wires. Located on the side of the throttle body. It tells the computer what your throttle plate is doing.
2) Idle Speed Control motor (ISC or IAC - Idle Air Control) - 6 wires. Located on the bottom of the throttle body. It opens and closes an air passage and makes your engine idle correctly.
3) Knock Sensor (a.k.a detonation sensor) - 2 wires. Located under your intake manifold, screwed into the engine block. This listens to your engine and if it detects any knock / detonation, it will tell the computer to retard the ignition timing to reduce the knock counts.
4) O2 Sensor - 4 wires. Located in the cast iron O2 housing on the side of the turbocharger. This measures Oxygen in the exhaust stream. It does this so that the computer can make sure the engine has the correct air/fuel mixture. If it is faulty, the computer will automatically go full rich with the engine. It knows that it is safer to be running rich than lean.
5) Mass Airflow Sensor (MAF) - 7 wires. Located inside your air filter box, remove the air filter, and you will see it. This sensor measures how much air is going into your engine. It detects air temperature and the speed that the air is traveling. Often times, these engines will inhale more air than the stock MAF can handle, thus, overrunning your MAF, and causing the ecu to cut fuel.
6) Crank Angle Sensor (CAS) - 4 wires. Located on the rear left side of the cylinder head. This is what you would rotate to adjust ignition timing, just like a distributor on an older car. It sends signals telling the computer where the crankshaft (and camshafts) are in their rotation. This helps determine when to fire spark plugs.
7) Power Transistor - 7 Wires. Located under on the drivers side front of the engine, screwed into the intake manifold. This interprets the computer / CAS signals and tells your coil to send spark out.
Ignition Coil - 3 regular wires + 4 spark plug wires. Located towards the front of the engine tucked into the intake manifold. This is the device that sparks your spark plugs. Exciting isn't it?
9) Injector Resistor Pack - 5 wires. This is the metal covered white block that was originally mounted to the vehicle's firewall. Different injectors need different amounts of resistance to make them work correctly. This is the resistor pack that makes sure your injectors and computer are receiving consistant pulses and not getting overworked/overheated.
10) Injectors - 2 wires per injector, 8 wires total. Located under the fuel rail between your intake manifold and the valve cover. These squirt the fuel into your engine. Simple enough.
11) Fuel Pump (FP) - 2 wires. This is located in the fuel tank of the Eclipses / Talons / Lasers, attached to the sending unit. This sends fuel to the fuel rail providing the injectors with the much needed fuel.
12) Coolant Temperature Sensor - 2 wires. This is located in the thermostat housing on the rear of the cylinder head. This tells the computer the engine temperature which is important if you want it to run smoothly in all temperatures.
13) Coolant Temperature Switch - 2 wires. This is located in the theromstat housing on the rear of the cylinder head. This tells your fans to turn on and off with the engine temperature.
14) The Engine Computer Unit (ECU) - 52 wires. This is the brain that makes your engine run. In determines all the engines variables and makes it run. If you do not give it all the variables it needs, it will not run correctly. These are known for burning capacitors on their circuit boards, causing the engine to surge, or not run at all. It is best to have the capacitors replaced before they go bad, because they can destroy the whole circuit board making it into nothing more than a nice conversation piece.
I will try and take pictures of all of these items, show you how easily I wired everything, and even get a little more in depth with it all. It was really much easier than I originally thought. Until nextime......Feel free to post any questions you may have.
