LA sequential fuel and spark EFI conversion
Sensor Wiring Details
Fuel Injectors- they have two pins that are not polarity sensitive, meaning, it doesn’t matter which one is power and which one is ground. Megasquirt switches the ground for the injectors. They will require constant 12V power. I separated mine by bank. Cylinders 1,3,5,7 are on one fuse, cylinders 2,4,6,8 are on another.
Water and air temperature- again, two wires. It’s a restive type sensor so it isn’t polarity sensitive.
TPS- these are potentiometers. For those that don’t know what this is, it is a variable resistor. They will have 3 wires, 2 of the wires will be the total resistance of the resistor. The 3rd wire will be what is known as the wiper of the potentiometer. It basically moves along the resistor varying the resistance as it moves. Typically, voltage is applied to one side of the total resistance and ground is applied to the other side. The voltage out of the wiper is the signal fed back into the computer. I can elaborate on this more if needed, but I’m sure a simple internet search would result in some pictorial to help understand.
Pic of TPS
IAC- The GM style is a 4 wire stepper motor. It has 2 coils inside it, one to move the plunger in, one to move it out. The MegaManual shows there are two different configurations for the coils. One configuration has the coils on terminals A&D and the other on B&C. While the other configuration is A&B and C&D. My IAC is the later. You can determine your configuration by using an ohmmeter and “ringing” out the terminals. Now, I learned this can be wired one of 4 ways. Before I knew how the software worked while the engine was running, I thought it was working correctly. (There’s a test function in the software) I later learned it was operating backwards. It took 2 wiring changes before I got it right. 3rd time’s a charm!
PIC of IAC
Cam Position- I was able to find a diagram online for the Jeep cam position sensor. Luckily it was correct.
TMAP- this sensor came with a wiring diagram and connector when I bought it.
I'll also add that this throttle body didn't come with any hardware. Of course all the threaded holes are metric. I took it with me to the hardware store and spent some time figuring out what sizes I needed. Luckily they had everything I needed. You will also notice I had to use a spacer under the throttel body. As you can see the sensor hang down below the bottom of it and contacted the intake.
Sensor Wiring Details
Fuel Injectors- they have two pins that are not polarity sensitive, meaning, it doesn’t matter which one is power and which one is ground. Megasquirt switches the ground for the injectors. They will require constant 12V power. I separated mine by bank. Cylinders 1,3,5,7 are on one fuse, cylinders 2,4,6,8 are on another.
Water and air temperature- again, two wires. It’s a restive type sensor so it isn’t polarity sensitive.
TPS- these are potentiometers. For those that don’t know what this is, it is a variable resistor. They will have 3 wires, 2 of the wires will be the total resistance of the resistor. The 3rd wire will be what is known as the wiper of the potentiometer. It basically moves along the resistor varying the resistance as it moves. Typically, voltage is applied to one side of the total resistance and ground is applied to the other side. The voltage out of the wiper is the signal fed back into the computer. I can elaborate on this more if needed, but I’m sure a simple internet search would result in some pictorial to help understand.
Pic of TPS
IAC- The GM style is a 4 wire stepper motor. It has 2 coils inside it, one to move the plunger in, one to move it out. The MegaManual shows there are two different configurations for the coils. One configuration has the coils on terminals A&D and the other on B&C. While the other configuration is A&B and C&D. My IAC is the later. You can determine your configuration by using an ohmmeter and “ringing” out the terminals. Now, I learned this can be wired one of 4 ways. Before I knew how the software worked while the engine was running, I thought it was working correctly. (There’s a test function in the software) I later learned it was operating backwards. It took 2 wiring changes before I got it right. 3rd time’s a charm!
PIC of IAC
Cam Position- I was able to find a diagram online for the Jeep cam position sensor. Luckily it was correct.
TMAP- this sensor came with a wiring diagram and connector when I bought it.
I'll also add that this throttle body didn't come with any hardware. Of course all the threaded holes are metric. I took it with me to the hardware store and spent some time figuring out what sizes I needed. Luckily they had everything I needed. You will also notice I had to use a spacer under the throttel body. As you can see the sensor hang down below the bottom of it and contacted the intake.
