Any questions you have before you begin buying, building and installing.
Installing Speeduino in an OBD1 Honda/Acura

Disclaimer: I am not responsible for any damage or injury that may be caused to you, your vehicle or any person or property as a result of this installation guide. Use the information in this article at your own risk. Consult your local authorities to verify that Speeduino is permitted on your road going vehicle.

Speeduino is an open source standalone Engine Management System (EMS) based on the Arduino mega 2560 platform. Speeduino can be installed as a placement to the factory Engine control unit (ECU) or as a piggyback ecu to work alongside the factory ECU. Speeduino is capable of working with most if not all factory sensors.

Speeduino offers full control of fuel and ignition table in addition to control of fuel pump, Idle control valve (IACV), Variable valve timing (VVT), Vtec, Boost control, launch control among other things.

Speeduino has 4 injector and 4 ignition channels, so its capable doing sequential fuel injection on a 4 cylinder engine. 6 and 8 cylinder support is also possible but due to the limited injector and spark outputs you will be limited to wasted spark or distributor spark configuration and batch injector configuration. In this article, I will cover Honda/Acura 4 cylinder support using the stock distributor and injector using the V0.3 series Speeduino. Pretty much any of the mainstream Speeduino boards with work on a Honda 4 cylinder, it just boils down to your preference. You can read up on the difference between the v0.4 and v0.3, NO2C, UA4C series Speeduino in the Speeduino wiki pages.

For this installation, you will need the following materials;

V0.3 series Speeduino PCB with components : You can buy the empty board and components from the Speeduino store or buy the board fully assembled. Please check app.php/page/buyfor full list of authorized Speeduino Resellers.

VR conditioner : for “conditioning” the signal from the stock Honda distributor so the signal is recognizable to the Speeduino. Available from the Speeduino store.

Arduino mega 2650 : This is essentially the processor “brain” of the Speeduino. ... er=product. Chinese variants of these found on eBay and amazon have been proven to work just fine.

Jumper harness : You will need some way to connect the Speeduino to existing factory harness. There are many ways to do this, you will only be limited by your imagination, skills and budget. If you are starting off with an OBD2 or OBD0 Honda you can get one of the OBD0/2 to OBD1 jumpers, cut off the OBD1 male connectors and just use the clipped wires to connect to the Speeduino screw terminals. If you are starting off with an OBD 1 car you can scavenge a female connector from an old factory ECU and use that to make a patch harness. Here is a video showing one way I did it

A view of my v0.3.2 with custom harness


Now that we have all our materials let’s put connect the laptop and go do some tuning. Wait a second ! we need to piece together this puzzle before we can go out pretending to be Shane Tecklenburg with our laptops.

Speeduino will need a few signals from your car’s engine sensors in order to function. In reality, you don’t need every one of these signals for the engine to run on Speeduino but you certainly need all of them for the engine to run to the best of its ability.

Engine Speed/RPM : Speeduino needs a signal from the engine to know what rpm its operating at and which cylinder needs spark and fuel.

Engine MAP/load : Speeduino has an onboard Manifold Absolute Pressure (MAP) sensor takes the place of the factory map sensor and senses the engine load, i.e. Speeduino will be able to differentiate idle, cruise and Wide-open throttle (WOT) based on MAP sensor reading.

Throttle Position : this signal comes from the factory throttle position sensor (TPS) and tells Speeduino how wide the throttle is opened.

Coolant Temperature : this signal comes from the factory coolant temperature (CLT) sensor and tells Speeduino how hot or cold your engine coolant is. This sensor is very vital to quick engine start up especially in cold climates.

Intake Air Temperature : this signal comes from the factory intake air temperature (IAT) sensor and tells Speeduino how hot or cold the air entering your engine is.

O2/ Air fuel ratio : this is an essential signal when tuning the engine to ensure optimal air and fuel mixtures during varying engine conditions. The factory sensor is a narrowband oxygen sensor and is not very useful to Speeduino. An aftermarket O2 sensor controller is needed for this. There are many options out there depending on your budget such as the Innovate LC1 or LC2, AEM UEGO to name a few.

Fuel injector Output : this signal comes from Speeduino and tells your factory fuel injectors when to squirt fuel into the engine.

Spark/ignition Output : this signal comes from Speeduino and tells your factory ignition system when to fire the coil to create a spark to ignite the air/fuel mix in the combustion chambers.

5v/Vref output : this is a 5v reference voltage output from Speeduino to 5v reference circuits in factory electrical system.

Sensor Ground : this is a ground output from Speeduino to sensor ground circuits in factory electrical system such as TPS, IAT and CLT sensors.

Idle Control Valve : Speeduino has an output/s to control the factory 2 and 3 wire idle control valve (IACV) on the throttle body. This valve is used to feed additional air to the engine to enable proper and stable engine speed at idle.

Note : for this installation, we will also be using the Fuel pump (FP), VVT/vtec outputs

Signal >>>>>>>>>>>>>> Speeduino pin name >>>>>>>>>>>> Honda pin name
Engine speed>>>>>>>>>>>>> VR1+ >>>>>>>>>>>>>>>>>>>>>>TDCP
............................................. VR1- >>>>>>>>>>>>>>>>>>>>>>TDCM
Throttle Position>>>>>>>>>>TPS >>>>>>>>>>>>>>>>>>>>>>>TPS
Coolant Temperature >>>>>> CLT >>>>>>>>>>>>>>>>>>>>>>> ECT
Air Temperature>>>>>>>>>>> IAT>>>>>>>>>>>>>>>>>>>>>>> IAT
O2/AFR signal >>>>>>>>>>>> 02 >>>>>>>>>>>>>>>>>>>>>>>>*connect to wideband controller
Fuel Injector output >>>>>>> INJ1 >>>>>>>>>>>>>>>>>>>>>>INJ1
.............................................. INJ2>>>>>>>>>>>>>>>>>>>>>>INJ2
.............................................. INJ3>>>>>>>>>>>>>>>>>>>>>>INJ3
.............................................. INJ4 >>>>>>>>>>>>>>>>>>>>>>INJ4
Spark/ignition output>>>>>> IGN1>>>>>>>>>>>>>>>>>>>>>> ICM1
5v/vref output>>>>>>>>>>>>>Vref>>>>>>>>>>>>>>>>>>>>>>VCC1 & VCC2
Sensor Ground>>>>>>>>>>>> GND>>>>>>>>>>>>>>>>>>>>>>SG1 & SG2
Idle Control valve>>>>>>>>>> IDLE>>>>>>>>>>>>>>>>>>>>> IACV
Fuel Pump>>>>>>>>>>>>>>>> FP>>>>>>>>>>>>>>>>>>>>>>>FLR
Vtec >>>>>>>>>>>>>>>>>>>>>S1>>>>>>>>>>>>>>>>>>>>>>>VTS
12 volts>>>>>>>>>>>>>>>>>>12v>>>>>>>>>>>>>>>>>>>>>> IGP1
GND (Main Ground)>>>>>>>>GND (J3 connector with 12v) >>LG1 & LG2

Jumper Configuration: You will need to set a few jumpers on the Speeduino board to ensure proper operation with your engine.
JP1: jumper IGN out to 5v
JP2: jumper center pin to VR.

Your Speeduino V0.3 should look something like this. In this pic an enclosure was not used, I highly recommend using and enclosure to protect the ecu.


Speeduino v0.3.2 fitted in custom 3d printed enclosure. CAD file for enclosure is available here:


Getting tired ? We are almost done. Go ahead and get your laptop Mr Tuner. We are not tuning just yet. Let’s set up a few more things. We need to flash the code/firmware to the Arduino/Speeduino. This is essential as the nice circuit board you just spent so much time putting together needs to be programmed to understand the signals you are feeding it. This is covered in the Speeduino wiki pages. ... g_Firmware

Next,we will need the program to enable you to tune the engine. Speeduino uses the Tunerstudio program for this. Latest version of Tunerstudio I available for download here; . Follow the wiki instructions on setting up Tunerstudio to work with Speeduino; ... unerStudio.

This video should help you with tunerstudio set :

Now that we have the firmware flashed onto the Speeduino and connected to your laptop with Tunerstudio, you will need a msq or tune file to start with. You can create one yourself if you are up to the challenge, its really not that difficult. In this videos I show you how.

You can download my basemap here. ... sp=sharing .

Basemap Specs

Engine : D15/D16
Vtec: Enabled 5500 rpm
Rev Limiter : 7000 rpm
Fuel injector Size: 240cc
Spark output: Single coil
O2 corrections: Off
Idle Control: ON (open loop)

This is not a "tuned" map and should only be used to get you started. Bigger displacement B/F/H series engines may need further tweaking for start up. I highly recommend that you take your car to a professional tuner to get your car properly tuned before you do any sort of hard driving.


With a basemap so you may need to sync your ignition timing in Speeduino in order for the engine to run or run properly. To do this follow these simple steps:

• Use some white paint or white-out to mark your crank pulley 16-degree mark. See factory service manual if you are unsure.
• Go to the follow settings; Spark>>Spark Settings>> Fixed timing. Enter 16 in this window and click the Burn button.
• Go to trigger set up window and under Trigger angle. You simply increase or decrease the number in this window till the crank pulley mark you painted lines up with the reference mark. See factory service manual if unsure on reference mark.
• When the timing mark lines up. Hit the Burn button and save the tune.

I made a video covering ignition timing syncing. You can View it here:

Now slowly adjust your VE and Spark tables to get your car however you want. I highly recommend you let a professional calibrate your car if you are unsure of what to do.

This guide is very is constantly being updated.

last updated February 28th 2019
Nice evo!!
One suggestion , put the example/startup map on github and link to it rather than suggesting you get emailed as I reckon the spammers will tag into your address pretty quick ........
dazq wrote:Nice evo!!
One suggestion , put the example/startup map on github and link to it rather than suggesting you get emailed as I reckon the spammers will tag into your address pretty quick ........
Thanks Darren I will work on it in the morning.
I wanted to say thanks evo_lucian for all your documentation. I've been using it for my own honda civic and a friend of mine who wants join the standalone club.
TCFOX wrote: Tue Aug 08, 2017 9:44 pm I wanted to say thanks evo_lucian for all your documentation. I've been using it for my own honda civic and a friend of mine who wants join the standalone club.
Thanks man. Im glad I could help. Perhaps you can start a thread and post some pics of your installarion, you may help someone.

I added a few pics to the first post

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