Frequently Asked Question

Honda Engine Sim
Last Updated 2 years ago


The Honda EngineSim was introduced to allow interactive bench testing of Honda ECUs. It supplies the signals from the distributor and many sensors so that an ECU can be fooled into thinking it has a functioning, running engine connected when it is safely on the bench. Controls are simple: on/off switches and knobs to adjust values up and down. Outputs like injectors, ignition control module (ICM) and solenoids can be observed via LEDs. This provides a means for testing ECUs outside of a vehicle and observing many common faults such as damaged injector drivers, fuel pump drivers and distributor VR sensor amplifier damage. Note: none of the sim versions can simulate idle air control valve behavior well enough to avoid a Code 14. This limitation is present in all hardware versions. (There is a bin available for download (ALT DOWNLOAD) which has the code disabled to use for testing.)

All 3 versions of the Engine Sim are covered on this page. Information on harnesses is provided for each revision.

The current version will NOT be available for purchase on the website. It is available for purchase directly from its creator, Dave Blundell (your friendly Moates Tech support) and will be sold directly from his company. At this time, PayPal is the only accepted method of payment, but you can use a credit card through paypal. Units will be available for $150+ship as pictured WITHOUT A HARNESS OR POWER ADAPTER. There will be $10 flat fee for USPS shipping for US residents. USPS and DHL available for international – please email for a quote with your address. (Sold out! Thank you everyone!)

Moving forward, all sales will be handled through Burton Racing and HA Motorsports who have stock of current models available, including with a harness and power adapter. ( as of 1/1/2022 )

Version 3 – 2019 Production

The third revision of the Honda Engine sim was introduced January 2019. It is supplied without a power supply or harness. It has terminal block connections suitable for building a harness using a harness pigtail. Some of the small annoyances of earlier versions such as injector LEDs that dimly glow when the injector is off have been fixed but it is largely the same unit with an increased number of channels compared to earlier models. Picture for identification purposes: (note: pre-production prototype pictured. production PCBs may vary in color)

sim v3 prepro

Sim V3 Power Supply

The Sim v3 is supplied without a power supply. The sim has a center-positive 2.1mm barrel jack for power. Alternatively, wires can be soldered to “CONST PWR” and “GND” instead of the barrel jack. There is not a single “right” power adapter for this – you could even use a variable voltage supply to investigate behavior of the ECU under different power conditions. In addition to many “wall wart” style adapters, the 12V rail of an AT/ATX power supply (yellow + black color wires typically) is suitable.

Power supplied to the sim will be supplied to the ECU, through a diode and PTC fuse. This means that whatever voltage coming in will go out to the ECU, minus 0.6V or so forward voltage (Vf) for a silicon protection diode. i.e. 15V in, 14.4V supply to ECU or 12.0V in, 11.4V supply to ECU. You will make the protection circuitry on the sim unhappy (and hot) supplying more than 17V but unregulated / marginally regulated supplies will work ok – the sim isn’t terribly picky about stable voltage. Maximum current draw for an ECU and all LEDs lit up simultaneously (unlikely scenario) was around 680ma. 400-500ma is a more realistic current draw for sizing purposes.

The PTC fuse on the sim is a thermal fuse. As current goes through it, it gets warmer. As it gets warmer, it’s resistance increases. More power = more heat. Eventually, the PTC fuse will enter a thermal runaway scenario where it cuts off. If you connect an ECU that is shorted out or otherwise drawing an excessive amount of power, you will see the sim “shut down” or all the lights get really dim except for the main power LED that remains lit whenever power is connected to the unit.

Sim V3 Wire Harness

The Sim V3 is supplied without a harness – you must construct your own. You will need a set of plugs from a 92-95 Honda Civic, Accord, Prelude, etc. It is recommended but not required to strip the connectors down to only the wires to be connected to the sim, removing any pins that will be unused. In some cases, it may be necessary to add wires to the harness for all Engine Sim functions. The recommended pins in the harness to use: (image stolen from Tech Library, thanks Katman!)

A Plug with wires: (wire colors will vary!)

OBD1 A Plug

B Plug with wires: (wire colors will vary!)

OBD1 B Plug

D Plug with wires: (wire colors will vary!)

OBD1 D Plug

After the connectors have been prepared, each wire needs to be stripped before inserting into the Engine Sim connectors:

OBD1 Plugs stripped

It’s helpful if the wires are approximately the right length to go where they need to. Putting them next to the Sim can help with this:

OBD1 Plugs and Sim

Insert each wire and turn the screw terminal clockwise to squeeze each wire tightly enough that it does not come out when you gently tug on it.


Final result: all wires connected to screw terminals and securely screwed down:



The second revision of the Honda Engine sim was offered with a connector and harness that could be disconnected and a 12V 1A wall wart power supply. This was sold directly through No spare parts are available for this. This was discontinued due to poor harness availability and unreliable wiring suppliers. Warranty service is no longer offered. We also are making the harness documentation available so that repairs to existing units can be made. Picture for identification purposes:


Harness documentation: Engine Simulator Diagram V2

Plastic connector for harness is AMP/Tyco 102387-6 Pins for black sim connector (102387-6) are AMP/Tyco 87523-6. Both are available from usual electronic parts distributors.

Version 1.0 – DISCONTINUED

The original Honda Engine Sim was offered with the harness hard-wired to the unit and a wall wart power adapter. This was sold directly by No spare parts are available for this. This unit was discontinued in favor of version 2 with a separate harness. Warranty service is no longer offered. These pictures are offered for identification purposes:

sim v1 prod

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