MS3Pro & MS2 MegaSquirt Output Test Modes

The MegaSquirt Output Test Mode is a robust tool for troubleshooting your EFI installation. This feature enables you to manually toggle inputs and outputs to test components such as coils and injectors. Multiple test modes are available and can be selected from the CAN-Bus / Testmodes menu. The specific modes accessible will vary depending on your ECU and firmware version.

Navigation: CAN-bus / Testmodes > Output Test Mode

Output Test Mode – Injector / Spark

This Output Test Mode allows you to test the injectors, ignition outputs, and fuel pump

There is no need to click the “Burn” button while using the test mode

Output Test Mode Controls

This is the main section for enabling and disabling the Test Mode function. Note: These buttons will be grayed out until the ECU is connected and communicating.

• Toggle Options: Enable Test Mode & Disable Test Mode

Fuel Pump

This option allows you to turn the fuel pump on and off, enabling you to diagnose issues such as wiring problems, fuel pump functionality, and fuel flow.

• Toggle Options: Fuel Pump On & Fuel Pump Off

Coil/Injector Testing

The coil testing runs continuously until stopped, while injector testing requires you to specify the number of pulses for flow testing with a graduated cylinder. Here is an explanation of the settings:

• Output Interval (ms): The time, in milliseconds, between firing each injector or coil
• RPM (Coil-on-Plug)(RPM): Calculated by by the ECU based on the output interval, this value represents the RPM at which the output would pulse at that speed on a running engine
• Injector or Coil Testing Mode:
  • Off: Disables testing
  • One: Tests only the specified coil or injector
  • All: Fires all injectors or coils up to the specified output simultaneously
  • Sequence: Fires all outputs one at a time, in order, until reaching the specified output, then cycles back to output A
  • Note: To start the test, you must select a mode other than Off
• Coil/Injector Output/Channel to Test: Specifies which output to test, or the last output to test if using All or Sequence testing mode
• Dwell(ms) or Pulsewidth(ms): Sets how long to pulse the output, in milliseconds. This should typically be at least 2.0 milliseconds to ensure a response
  • Note: Values below 2.0 milliseconds may not provide sufficient time to properly dwell a coil or open an injector
• Total Number of Injections:  the number of injection pulses in each test

Output Test Mode – I/O

This Output Test Mode is used for testing outputs that are controlling relays, solenoids, or lights

Output Test Mode Controls

This is the main section for enabling and disabling the Test Mode function. Note: These buttons will be grayed out until the ECU is connected and communicating.

• Toggle Options: Enable Test Mode & Disable Test Mode

Pulse Settings

• Pulse Frequency: frequency of the pulsed output
  • When testing an output it is best practice to select the HZ recommended by the manufacturer to ensure proper operation. There are however instances when using a different HZ during testing can be helpful.
    • • Using a lower HZ on most solenoids during testing will make them hum or ‘click’ loudly, this can be helpful when the solenoid is installed somewhere hidden.
• Pulse Duty Cycle(%): duty cycle of the pulsed output
  •  This is how long the pulse is ON, the more duty you apply the longer the pulse will be.
    • If we were controlling an LED light at a low duty% the light would be dim, as we increase duty% the light would become brighter.
  • Generally a value of 0 is OFF, and a value of 100 is ON. Some solenoids and devices have a minimum and maximum duty that they will function between.
    • A PWM fan controller may not turn on until 20% duty and may be at full speed by 80% duty.

Outputs

• Output Channels: this is a list of outputs that can be tested
• Toggle Options:
  • Off: this turns Off the enable testing modes of Pulsed or On
  • Pulsed: this pulses the output based on the Pulse Settings above
  • On: this turn the output On

Output Test Mode – Idle Valve

This Output Test Mode is used for testing idle valve outputs or either Stepper or PMW based on the Idle Valve Type chosen

Note: Idle Valve testing can be used with the engine running or stationary

PWM Valve

• PWM Idle Duty% (0-100)(steps): this is the commanded Duty Cycle % for the idle valve on a 0-100% scale
  • Engine Running: as you increase the percentage the idle valve should increase
  • Engine Stationary (not running): with the valve removed from the engine you should see the valve move as the percentage is increased or decreased
  • This is helpful for testing the minimum and maximum duty% for the idle valve.
• Start/Stop Testing:
  • Enable Test – Run Position – this enables the testing process
  • Stop Testing – this disables the testing process

Stepper Valve

• Idle Valve Homing Steps (steps): number of steps to move valve in homing operation
• Idle Valve Step (0-255)(steps): Desired valve position
• Start/Stop Testing:
  • Enable Test – Home Position:
  • Enable Test – In/Out Cycle:
  • Stop Testing: this disables the testing process