Back in 2014 I had just bought a 1955 split screen camper. It had the usual 1584cc twin port engine fitted with a 34PICT carburettor. I’d swapped the 009 distributor to a vacuum advance one but I couldn’t get rid of an annoying flat spot just off idle. After spending many hours swapping carburettor jets and fiddling around with different distributor setup I came to the conclusion that the only way to get the engine to run as I wanted was to replace the carburettor with a fuel injection system.
I started looking for an ECU I could use on my VW from another vehicle. ECU’s fitted to modern cars are very complex, they don’t just run the engine, they control the door systems, the lights, some are linked to one key. Motorbike ECU’s are much simpler and I found some software that I could use to re-map Triumph parts.I I bought a couple of ECU’s originally fitted to 4 cylinder 600cc Triumph and two sets of throttle bodies from a 3 cylinder triumph. The throttle bodies were the only ones I could find that were bolted directly to the cylinder heads, most were attached via rubber tubes.
I got this setup running on a spare 1600cc engine pretty quickly but I came across some issues
I started looking for an alternative ECU, there are lots of aftermarket units on the market but most of them cost in the region of £800 to £1000. I regularly drive my camper onto the continent maybe I’m being over-cautious but I wanted to be able to carry a spare unit, I didn’t want to find myself stranded with a damaged ECU in the middle of Germany, it’s not like I can call VW for a replacement. I couldn’t have the better part of £1000 tied up in an ECU I might never use.
I’d been watching with interest the development of something called ‘Megasquirt’. Some guys in the US had decided to design their own ECU presumably because they also found the aftermarket stuff too expensive or unsuitable for their applications. They went from a relatively simple plug in processor to something they called Megasquirt 2 then Megasquirt 3. Megasquirt 3 was the one that interested me, finally they’d developed something that could drive multiple injectors and coils as well as control peripherals like an idle speed control valve. Unfortunately they continued to use their original control board with the same old power supply and input circuits. The Megasquirt 3 add-on board was connected to the base board via 3 IC sockets, each with 68 connections. As a designer of high-reliability electronics this didn’t seem like the right way to go about it.
I bought myself a Megasquirt 3 daughter board and set about designing my own ECU around it. My ECU is all on one printed circuit board designed to fit into a sealed enclosure using sealed automotive connectors. This is the circuit board you can see on the home page of 1584 Engineering. Finally had the basis of a reliable and economically priced Engine Control Unit. This would be the basis for my fuel injection system.
The specification of my ECU is as follows