The Nippondenso Pin Adapter Board has some extra circuitry for 3 wire IAC control as well as for the stepper valves found on many Toyota and Mitsubishi engines. As with the main board assembly, if it’s important not to get a component backwards, we have marked the step with (+/-).
3 wire IAC Control
- Install resistors R5A through R8A in their respective slots.
- (+/-) Install D1A and D2A, making sure to point the banded end to the right.
- Install Q3A.
- Bolt the 52 pin connector to the board with the included screws and solder into place.
- Install the adapter board in the lower half of the case, and bolt the endplate into place. The adapter board needs to be flush with the endplate
- Now for the tricky part – installing Q1A and Q2A. These need both a mica insulator and heat sink compound. These transistor slip into the holes on the PCB and then bolt to the end plate with a 4-40 screw. Then solder it into place.
The 3 wire IAC circuit has five jumpers on a header on the far left of the adapter board. Here is how to connect these jumpers.
- The IN jumper connects to the IAC output on the main board.
- The OPEN jumper connects to the opening coil wire on the 55 pin connector.
- The CLOSE jumper connects to the closing coil wire on the 55 pin connector.
- The 12V jumper connects to a 12 volt source on the main board.
- The GND circuit connects to any GND jumper on the main board. You must have either the GND jumper in the 5 pin header or at least one of the GND pins in the 2 pin header to the right of the connector grounded for the IAC circuit to function.
Note that you do not need to add any flyback diodes on the main board if using the 3 wire IAC control circuit. It has flyback protection built in.
Stepper control with a MicroSquirt module is supported in the latest V3.0.3 MS2/Extra builds. You cannot run a stepper and sequential injection at the same time.
- Install resistors R1A through R4A at the edge of the board.
- Install the stepper driver IC, U1A, with the notched end pointing to the left edge of the board.
- Install capacitors C1A through C3A.
The stepper IAC circuit has ten jumpers on a header on the far left of the adapter board. Here is how to connect these jumpers.
- PT6 and PT7 connect to the PT6 and PT7 terminals on the main board.
- PIB connects to the PIB4 terminal on the main board.
- The 5 volt connection connects to the 5 volt output pin on the main board.
- You can connect the 12 volt pin to either a 12 volt terminal on the main board or a 12 volt source from the ECU connector.
- The GND pin must be grounded to a power (not sensor) ground for the IAC to work.
- Pins 1A and 1B connect to opposite ends of one coil on the IAC valve, and pins 2A and 2B connect to the other coil. We will provide details on specific IAC applications in our model specific documents.