Speeduino – Arduino based engine management (opens in new tab)

Case in point: I have a Renault R5 GTL with a Renix pseudo-ECU module [1] taken from a Renault R11 TX, along with its camshaft, head, double barrel carb and other bits. It has inputs only for manifold vacuum & crankshaft sensor (some support a knock sensor, mine does not). A crude ROM map is applied to the advance curve from just those two parameters. It works really well, but that's it, no way to change or fine-tune anything.

> while testing showed it produced more power and better emissions

A customizable "ECU" similar to the Renix approach that does EXACTLY this, would be a godsend to me (and also my local old Fiat/Lada/you-name-it heads). At these small displacements, we just don't care how the engine sounds: every HP gained is a win.

[1] http://boursinp.free.fr/pdgdiag2.htm

PS. Yes, I know an 123ignition dizzy is what I need, but they're way too expensive - and proprietary. Where's the fun in that?

And if this thing breaks the engine just do nothing?

Did you build any hardening or redundancy into it?

How hard would it be to made that user-selectable? Because I would guess that some would prefer it that way while driving in the city.

Can you send CAN bus commands to the ECU?

Around that time a friend was having car problems. He described the symptoms to me. I looked up the type of fuel injection used on that car, which sensors it used etc, and recommended they replace a specific sensor, without ever having even seen the car- all based on my knowledge from Megasquirt. I found out later that it worked, the engine ran much better. It's amazing what a bit of open source knowledge can do :)

I have to support my locals though, Haltech and Link. They have a recent video on the Haltech YouTube channel of a tour of their facilities. It's no Toyota factory line, but feels very pragmatic and I love that they still do it in house.

Now if you go back in time far enough to pre-WWII designed vehicles it was common to have two ignition systems with a massive mechanical lever to switch between "magneto" and "coil" based ignition for gas engines in military engines. Coil driven spark plug systems had advantages but the magneto system was much more reliable by virtue of having no moving parts. Diesels had a slight advantage here in that there was no ignition system as such to fail.

All Audi and VWs recently have drive by wire system that opens the throttle, drives ignition coils, and triggers fuel injectors electrically. It’s not like there is much to go wrong. I did find a very high accuracy, temperature compensated Crystal resonator which makes sense for sending timing signals in a harsh environment.

Get yourself electronic ignition (Pertronix is a recommended brand) which replaces points and basically uses solid state electronics to fire the spark plugs, making them run much better and no more messing with points.

All engines need timing, but modern distributor-less motors do it automatically; timing should be a set it and forget it thing for the most part.

Then your carburetor is likely the issue for running rough, hard to start, etc. You could get a different more modern carburetor, but switching to fuel injection may be the way to go if you just want "turn the key and go". They make fuel injection systems that look and mount just like a carburetor but use more modern tech - look at FiTech, or Holley for solutions. Those are going to require you to add a sensor to the exhaust and a couple sensors around the motor (all included in the kit, but work to add), plus you'll probably need a new fuel pump that can put out much higher pressure (fuel injected cars use ~40-60psi fuel, carburetor is more like 3-5psi).

It stinks because it's burning raw fuel and you're not used to the smell of that thanks to today's cars with catalytic converters - they do sell them aftermarket that you could add in to your exhaust system as well.

At the end of the day, it's all very possible and there are open source projects like Megasquirt that could be a place to start, but going the open source route will be even MORE "fiddling around" than your current setup, so you may want to look at off-the-shelf EFI conversions. At least do yourself a favor and get Pertronix electronic ignition - it's a total game changer in terms of ease of starting, smoother running, and less hassle, and it doesn't cost much and is easy to do.

But for a digital solution, you're looking at an EFI conversion kit, with a ready made wiring harness to convert the necessary items to run the EFI. It is common enough to do that you'd have no trouble sourcing advice and if you like that kind of thing it would be a great project. I see Holley do good looking kits but I can't speak from experience sorry.

The difference between an ECU run V8 and an "analog" V8 is mostly in electronic control of ignition timing and fuel injection, and all the sensors needed for the ECU to know what's going on. I think just replacing the carb with an EFI carb kit would be a great project, but to take it further you would need to ditch the distributor and use coilpacks and ignitors controlled by the ECU, and a timing sensor to sense the position of the crank. At that point you need a full ECU and speeduino would do the trick, but there are supported manufactures of aftermarket ECUs as well like Haltech, Holley, Motec, and Link.

[0]: https://wtmtronics.com/product/carbumate/