In the latest part of my dune buggy project series, I showcase an experimental two-signal electronic fuel injection (EFI) system! This system uses a manifold absolute pressure (MAP) sensor and the distributor points, along with the ideal gas law PV=nRT, to determine how much fuel should be metered into the engine by an injector.
This system is currently only a prototype an needs significant refinement in safety and performance before being put into permanent road service. If you try anything you see in this video yourself, you are doing so at your own risk.
Here is a link to the GitHub repository where I have uploaded the microcontroller code and circuit schematic:
https://github.com/JohnPattersonConsulting/DuneBuggyEFI
Thanks for watching DielectricVideos, and stay safe!
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I'm absolutely amazed that this can be put together with hardware store plumbing parts, rubber coupler, PVC pipe, and a cheap hobbyist microcontroller with home written code. About 50 years ago I did a fair bit of tinkering with lawnmower and small motorcycle engines. I was really happy if I could get them to run (and idle) decently and maybe wring a tiny bit of extra power out of them at wide open throttle.
I have a need for a 2 stroke open loop efi if you ever get bored 🙂
Since it is miscounting on low rpms you may need a low pass filer circuit on the signal to clean it up more
Sounds like rocket science to me
Very well done. I would change the points and get a hall effect sensor and then you will make a nice square wave for the ecu to read
I have a 1965 bug with an 1835 and I could seriously use your help to build an electronic fuel injection system.
I’m in Arizona as well.
Is the carburetor functioning as carburetor and fuel injected added? Or is the carb disabled and only the fuel injector working?
Very impressive video and crystal clear explanation. Thank you. And subscribed!
I ran across your channel searching ways to build a fuel injection system for my 1973 super beetle sports bug. Your knowledge of the electrical design and operation is awesome and ur explanations are concise!
In ur about tab, you state that you’re not an engineer. Dude, I have an electrical engineering degree. With that, at least I can say you are indeed practicing engineering. Not by title but by practice; your are an engineer. And it seems you’re developing to be a phenomenal engineer!
Keep at it dude!
I would like to thank you very much for the research you made for me. You saved a lot of time and effort to me.
Wow, very interesting indeed, awesome ingenuity. May I ask where you learned the basic programming skills needed to do this? I'm a long time tinkerer/mechanic, handy as they get, but computer programming is still black magic to me. I would LOVE to build a FI system based on a few simple inputs like this. I'm daunted by Megasquirt, but I've tuned carbs all my life to do anything I want really, including boosted applications. Thanks again, hope you have time to respond.
What you're doing is awesome! is there a way for you to explain in a video your connections, even how your arduino is connected? please!
Saludos desde mexico!
Since the introduction of watered down fuel the motorcycle owners have suffered a lot …a set up like that with a lean and rich control on the dash board ?
Take the CDI signal to trigger the injector .
Absolutely amzing video, liked, saved, and subscribed, very impressive setup you have. cant wait to see more from you
need a TPS for fast tip in.
What micro controller did you use? i appreciate your passion for this project
Does your fuel get hot? I've found that when I use a high pressure/high waste return, the fuel starts vaporising from excessive heat. PROBLEM
Waww amazing very nice good work thanks
THis is very impressive, i hope you will mak very many similar videos in the future 🙂
I love the design, but isnt this current design just a more complicated carburetor? It uses map to determine how much fuel is being input which is essentially what a jet will do on a carburetor albeit not as accurately and without input from rpm directly.
the minute 8:31 the resistance of the transistor what value has 15 ohm? and the resistances of how many watts are they?
We usually run about 100mA through the points just to burn off any light surface contamination. I'd have a driver transistor driving the injector transistor, that 15Ohm does very little. As for the RPM sensing problem, you could gate your interrupt so it's only enabled when you're expecting it ie have a background averaging routine, which should filter out spurious triggers, so if your average rpm is 2000rpm (33Hz, 30ms period, for a 4cyl) disable the interrupt for, say, 20ms. This disable period will vary dynamically with average RPM. An inductor and some sort of voltage clamp at the input to the 7805 is a good idea as you can get huge (400v!) spikes on a vehicle electrical system when inductors (wiper motors, fuel pumps etc) are switched. Hope that helps.
Are you reading a script (written by you I mean) or are you that good?
one other thing what electronic componants do you need i cant promise i have them but i do have a lot of componants i have many ive harvested and collected as well as a 42 gallon contractor bag of mostly industrial control boards and a 30 gallon can with a few cars worth of wiring harness a majority of which are dueitch connectors and i definately want to send you an arduino due i have about 5 of those (i like promoting inelligence and free thought and its obvious youre pasionate about this as am i and have taken the time to research your shit)
kid your bright as hell keep it up
Hey man thanks for sharing. I’ve been piecing together a 34mm throttle body. I am using Map, tps, and a conditioned VR signal from a common motorcycle ignition pickup coil to start.
Impressive. Most people could pull off an efi conversion with a kit or ebay parts, but it takes a real genius to MacGuyver a system together like that. You're even sporting the trademark vest!
Awesome job, man. Both the build and this video explanation. I can only look on in envy.
if you want to get volume measured more accurately for fun add a Mass Airflow Sensor post filter. you can tune more accurately for different elevation. Speed Density is a good way to tune but only for your given elevation. Find a way to convert the distributor to a hall effect sensor signal, then you can also control your engines timing accurately. to get proper throttle tip in fuel enrichment find a way to get a tps signal. if you can Find and old TBI set up off any late 80s gm or mopar trucks you will be in business, Modern Harley Davidson Carbs are fuel injected as well using gm sensors and ev2 injectors. all will work on your little bug. https://speeduino.com/shop/2-home
props with how cheap you made this work keep it up kid
Loved it and always wanted do it. I never imagined you could inject before the throttle body. Given me a whole lot of enthusiasm to try out some of my ideas on 2 stroke outboards. Maybe be brave enough to post a video but thanks and well done.
Congrats, great job, simple but effective! Thank you for share your experience and knowledge!!!