Honduino OBD2 DPFI - V5

The Honduino OBD2 DPFI is an advanced aftermarket engine control unit (ECU) designed specifically for Honda vehicles with DPFI (Dual Point Fuel Injection) systems. This comprehensive guide covers the complete setup, calibration, and advanced configuration of the V5 version of this ECU.

This documentation covers:

• Pre-installation firmware updates and software setup
• Basic ECU configuration:
  • Trigger wheel settings
  • Ignition parameters
  • Injection configurations
• Vehicle integration and sensor calibration
• Advanced features including:
  • Wideband O2 sensing
  • Launch control and anti-lag
  • Boost control
  • Custom output configuration (CEL, shift lights)
• Complete pinout diagrams and connection references

Whether you’re upgrading from a stock ECU, migrating from an older version, or installing a new aftermarket unit, this guide provides detailed instructions to achieve optimal performance with your Honduino OBD2 DPFI V5.

Before connecting the ECU to the car

Before mounting the ECU to the vehicle, some pre-installation configurations should be performed.

Updating the firmware (optional)

Download and install STM32CubeProgrammer V2.14 Download the latest FIRMWARE Click on the BOOT button on the board and plug the USB cable into the computer In STM32CubeProgrammer, select USB, refresh the devices, select the ECU, and connect. Go to the “Erasing & programming” menu, browse, and select the firmware.ini file extracted before. Insert the start address: 0x0800000 Select the boxes: “Run after programming”, “Full chip erase” and “Download file” Click “Start Programming” You successfully updated the firmware! Now, close all the STM32CubeProgrammer windows and restart the ECU by clicking the RESET button or unplug and plug the USB cable.

Connecting to the software

Download and install: TunerStudio Plug the USB, it will automatically open a virtual drive with a file Extract it, and save it on your desktop. Open TunerStudio, create a new project, click “Other / Browse” and select the firmware.ini file extracted before. Use RS232 Serial for USB connection or Bluetooth direct

Base settings

Configure the number of cylinders, engine displacement in liters, firing order, and fuel strategy.

Ignition (Distributor / COP)

WARNING: Use only smart coils or dumb coils with external igniters.

The ICM switch needs to be adjusted based on the ignition setup. (CRITICAL)

Configure the Spark Mode and Output Mode

CRITICAL WARNING: If the output mode isn’t configured correctly, the coil(s) will overheat and potentially get damaged. If the ignition is ON and the coil starts to heat up, the configuration is likely incorrect.

Spark mode:

• Single coil: Distributor
• Individual coils: Smart coils in sequential mode

Ignition output mode:

• Honda distributor DPFI coil: Default (Going Low)
• Most of the smart coils: Default (Going Low)

Ignition voltage output: select the voltage for each pair of ignition output via the jumpers:

H1 + H2 H3 + H4 H5 + H6 H7 + H8 H9 + H10 H11 + H12

• Honda distributor: 12V
• Most of the smart coils: 5V

If using individual coils: Connect each coil signal wire to the OBD1 C connector.

C5: Coil 1 (High side 1)
C7: Coil 2 (High side 2)
C9: Coil 3 (High side 3)
C11: Coil 4 (High side 4)

WARNING: Be sure to read all sections on ignition so you don’t damage any coils.

Injection

WARNING: Use only high-impedance injectors (> 8 ohms) or low impedance with a resistor box.

Configure the outputs that correspond to each cylinder.

Injector base settings

• Injection mode
• Injector flow
• Compensation mode
• Dead time

Temperature sensors

Coolant temperature sensor

Intake temperature sensor

Trigger wheel

Configure the trigger wheel according to your distributor disc:

Stock trigger disc:

24-1 trigger disc:

Connect the ECU to the car

Throttle Position Sensor

Adjust the Primary minimum (ADC) and Primary max (ADC) until the TPS reads 0% without pressing the throttle and 100% at full throttle.

MAP sensor

Any MAP sensor can be used, but the most used is the stock one on input A4.

You can also solder an onboard MAP sensor to Analog Input 5 or connect to free analog input.

Radiator fan

A valve controls the radiator fan mechanically, but the ECU can activate the relay independently by an unused Low side output.

Ignition base timing (same as the rotation of the distributor)

To sync the ignition timing with the engine, it’s necessary to adjust with the help of a Timing Light gun.

1. Disable the injection (if the car starts, skip this step)

2. Change the timing mode from dynamic to fixed, so the ECU fires the coil always on the 0-degree angle.

3. Use a white sharpie to mark the 0-degree mark on the crank pulley. The crank pulley has four marks, with the alone mark of the four being 0 degrees (TDC).

4. Attach the timing light clamp to spark plug wire 1, ensuring the arrow points toward the spark plug.

5. Adjust the Trigger Angle Advance value until the 0-degree mark on the crank pulley aligns with the pointer on the distribution cover.

6. Unlock the timing, so the ECU sends the ignition table values.

The timing is synced, now start your car 🥳🥳🥳

Idle control

Adjust the idle when the engine is at its normal operating temperature.

Idle Target RPM is used to control the idle in closed-loop mode.

Warmup Idle Multiplier adjusts the value based on the open-loop idle setting.

Closed-loop idle adjusts the idle by a PID algorithm.

Closed-loop idle timing adjusts the idle by advancing or retarding the ignition timing.

VTEC solenoid

This engine doesn’t have VTEC solenoid, but you can change to a head with VTEC.

0 = OFF
100 = ON

Vehicle Speed Sensor

Air Conditioner

Extra features

Wideband

To tune the VE table, a wideband sensor for measuring the air-fuel ratio is necessary.

1. You can either connect an LSU 4.9 sensor directly to the onboard controller or use a 0-5V signal from an external controller via an auxiliary analog input.

OBD1 C connector	LSU 4.9 sensor
C2	5 (IA)
C4	6 (NERMEST)
C6	1 (IP)
C8	2 (VGND)
C10	3 (HEATER-)
C12	4 (HEATER+)

2. Configure the wideband linear output values

Launch control

Launch control is used for… I mean, for spitting flames, lots of 🔥🔥🔥!

Select the activation mode: It can be Speed-based, Launch, Clutch, or Brake button.

If you choose to use a button, some cars have clutch switches, but most will need to be wired to a switch that sends a ground signal to pin OBD1 B7 (Aux Digital Input D2) when the clutch is pressed.

• Launch RPM: A secondary Rev limit engaged by the driver to help launch the vehicle faster.
• Ignition Retard Adder: Range from Launch RPM for Timing Retard to activate.
• Hard Cut RPM Adder: Range from Launch RPM to activate Hard Cut.
• Smooth Retard Mode: Interpolates the Ignition Retard from 0 to 100% within the RPM Range.

Anti-lag

ANTI-LAG is used to help reduce turbo… I mean, for spitting flames, lots of 🔥🔥🔥!

Wire a switch that sends a ground signal to an unused auxiliary digital input.

Boost control

A boost controller is a device used to increase the boost pressure produced by the turbocharger.

1. Connect the negative wire of the boost controller valve to an auxiliary low-side output.

2. Activate a boost limit to protect the engine from overboost.

• Boost cut pressure (absolute): MAP value above which fuel is cut in case of overboost.
• Boost cut pressure hysteresis: If hard cut is 160kpa, and boostCutPressureHyst is 10, when the ECU sees 160kpa, fuel/ign will cut, and stay cut until 160-10=150kpa is reached.
• 160kpa absolute = 100 kpa atmosphere + 60 kpa of boost

3. Select Open-loop mode and the auxiliary output. Open-loop: Regulates the boost valve’s duty cycle according to the percentage values in the control table.

4. Configure the Boost control open-loop table.

5. It’s possible to enable the Open + Closed-loop and control the boost more precisely. Open + Closed-loop: Regulates the boost valve’s duty cycle using the open-loop table, combined with a PID algorithm and a target table.

CEL: Shift / Warning light

The engine light can be used as a programmable output. I prefer to use it as a shift indicator and for coolant temperature warnings.

0 = OFF
100 = ON

Tachometer

The stock distributor coil sends the RPM signal to the cluster, but the ECU can also control it. When converting to coil-on-plug, the signal from the distributor stops working, so the ECU must provide it.

1. Select the output Low-Side 11 to send the RPM signal.

2. If you’re still using distributor coil and want to control the RPM by the ECU, remove the wire:

3. Select the TACH switch to YES.

Auxiliary inputs/outputs

LOW SIDE: Controls injectors and valves using a ground signal, handling up to 10A.

• L19 to L24: Configurable for any auxiliary function

HIGH SIDE: Controls smart ignition coils with 5V or 12V signals.

• H5 to H12: Configurable for any auxiliary function

ANALOG: Inputs for sensors with a 0-5V output or for temperature sensors.

OBD1 B connector	Tunerstudio Analog Input	Function
B2	Analog Input 5	On-board MAP sensor
B4	Analog Input 7	Free
B6	Analog Input 8	Free
B8	Analog Input 9	Knock Input
B10	Analog Input 10	Free
B12	Analog Input 11	Free
B14	Analog Input 12	Free

NOTE1: If no sensor is wired, it can be repurposed for any other function.
NOTE2: To use temperature sensors, the corresponding input switch must be set to the ON position.

DIGITAL: Inputs for hall sensors (0-5V)

OBD1 B connector	Tunerstudio Analog Input	Function
B1	Digital Input 6	Free
B3	Digital Input 7	Free
B5	Digital Input 8	Free

NOTE1: If no sensor is wired, it can be repurposed for any other function.

SENSORS: Provides 5V output and ground for powering pressure and temperature sensors.

OBD1 B connector	Tunerstudio Analog Input	Function
B7		+5V
B9		+5V
B11		+12V
B13		Ground
B15		Ground
B16		Ground

EGT: Inputs for exhaust temperature sensors (Type K)

Drive-by-wire: Controls a 2-wire electronic throttle body or ITB.

• OUT- & OUT+: Output for ETB motor
• 5V: Power to the potentiometers
• GND: Ground to the potentiometers

NOTE1: If no sensor is wired, it can be repurposed for any other function.

PINOUT: OBD1 DPFI

Connector A

OBD1	FUNCTION	TUNERSTUDIO
A1	Injector 1 / 4	Low Side 1
A2	Ground
A3	Injector 2 / 3	Low Side 2
A4	Ground
A5	VTEC Solenoid	Low Side 3
A6	Brake Switch	Digital Input 3
A7	Fuel Pump Relay	Low Side 4
A8	FAN Relay	Low Side 5
A9	Purge Solenoid	Low Side 6
A10	Alternator Control	Low Side 7
A11	IACV N	Low Side 12
A12	CEL	Low Side 9
A13	IACV P	Low Side 10
A14	A/C Clutch Relay	Low Side 11
A15	Free: Injector	Low Side 12
A16	Distributor ICM	High side 1
A17	Free: Injector	Low Side 13
A18	Clutch Switch	Digital Input 4
A20	A/C Signal	Digital Input 2
A21	Power Steering Switch	Digital Input 5
A23 / A25	+12V ignition
A24 / A26	Ground

Connector B

OBD1	FUNCTION	TUNERSTUDIO
B1	Free	Digital Input 6
B2	Onboard MAP sensor	Analog Input 5
B3	Free	Digital Input 7
B4	Free	Analog Input 7
B5	Free	Digital Input 8
B6	Free	Analog Input 8
B7	+5V for sensors
B8	Knock Input	Analog Input 9
B9	+5V for sensors
B10	Free	Analog Input 10
B11	+12V for sensors
B12	Free	Analog Input 11
B13	Ground for sensors
B14	Free	Analog Input 12
B15	Ground for sensors
B16	Ground for sensors

Connector C

OBD1	FUNCTION	TUNERSTUDIO
C1	Free	Low side 14
C2	LSU 4.9 - PIN 5 (IA)
C3	Tachometer Output	Low side 15
C4	LSU 4.9 - PIN 6 (NERMEST)
C5	Coil 1	High side 1 (E15)
C6	LSU 4.9 - PIN 1 (IP)
C7	Coil 2	High side 2 (E14)
C8	LSU 4.9 - PIN 2 (VGND)
C9	Coil 3	High side 3 (E13)
C10	LSU 4.9 - PIN 3 (HEATER-)
C11	Coil 4	High side 4 (E12)
C12	LSU 4.9 - PIN 4 (HEATER+)

Connector D

OBD1	FUNCTION	TUNERSTUDIO
D2	Free - Hall Input	VR/Hall 2
D3	Vehicle Speed Sensor	Digital Input 1
D7	TDC	VR/Hall 1
D8	Tachometer Output	Low Side 15
D9	Free	Low Side 16
D10	Free	Low Side 17
D11	Throttle position sensor	Analog Input 1
D13	Manifold air pressure sensor	Analog Input 4
D15	Intake air temperature sensor	Analog Input 3
D16	Free	Low Side 18
D17	Coolant temperature sensor	Analog input 2
D19	MAP ground
D20	TPS ground
D21	MAP +5V
D22	TPS +5V