efi

4 Articles

Small Engine Gets DIY EFI Upgrade

May 18, 2026 by 27 Comments

Small internal combustion engines usually keep things simple, relying on carburetors to handle metering the correct amount of fuel and air. Recently, [Carlos Takeshita] decided his small engine could use an upgrade in the form of electronic fuel injection (EFI).

The build began with a Predator 212, a popular gasoline engine from Harbor Freight. [Carlos] set about kitting it out with a missing tooth trigger wheel to measure the crankshaft position with a hall effect sensor. The engine also scored a custom-built aluminium fuel cell, complete with a high-pressure fuel pump and regulator suitable for driving the solitary fuel injector installed in the custom intake manifold. A Teensy 4.0 is charged with monitoring a manifold air pressure (MAP) sensor and the crank position, and choosing when and how long to fire the injector to dose the engine with the correct amount of fuel. Files are on GitHub for those eager to dive deeper.

It can be quite a job to convert an engine to run with electronic fuel injection, but you’re certain to learn a lot during the install and tuning process. We’ve featured similar builds many times over the years.

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Mac EFI PIN Lock Brute Force Attack (unsuccessful)

February 26, 2013 by 82 Comments

[Oliver] wiped the hard drive from a Macbook Pro using the ‘dd’ command on another machine. This does a great job of getting everything off the drive, but he was still faced with the EFI PIN lock protection when he tried to put it back into the Mac. You used to be able to clear the NVRAM to get around this issue, but that exploit has now been patched. So [Oliver] set out to use a microcontroller to brute-force the EFI PIN.

You can read his back story at the link above. He had the chance to enter a 4-digit pin before the format process. Now that he’s wiped the drive the code is at least 6 characters long, which is a lot more possibilities (at least it’s numeric characters only!). To automate the process he programmed this Teensy board to try every possible combination. It worked great on a text editor but sometimes the characters, or the enter command wouldn’t register. He guesses this was some type of protection against automated attackers. To get around the issue he added different delays between the key presses, and between entering each code. This fixed the issue, as you can see in the clip after the break. Unfortunately after two 48-hour runs that tried every code he still hasn’t gained access!

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Digidash: Digital Dashboard For Megasquirt

May 31, 2008 by 5 Comments


The Digidash project is an open source digital dashboard designed just for the megasquirt EFI system we mentioned in our diy EFI motorcycle post. Unfortunately, the site doesn’t link the hardware design. From the description, I’m assuming that it’s essentially a graphic LCD driven by an Atmel microcontroller that talks to the Megasquirt to get the display info.

Mpguino: Injector Level Fuel Montoring

May 29, 2008 by 28 Comments


[dcb] posted about his work on the mpgduino mpguino. The project uses an arduino with a LCD display to monitor fuel consumption based on vehicle speed and the pulses of the fuel injectors being fired. It’s definitely an interesting project given current fuel costs and the passive nature of the project. You can easily tap the wires needed for the monitor and remove it without voiding your warranty (not that we really care).