EFI Conversion with Megasquirt


Megasquirt is the creation of Bruce Bowling and Al Grippo (may they live long and prosper) who were generous enough to publish on the web.Since then it has achieved a life of its own with software, firmware and hardware contributions from an assortment of very clever people.

Visit the website at www.msefi.com, it is quite an eye opener.


Why Convert?


It has been a long held ambition of mine to convert at least one of my Triumphs to an electronically managed fuel injection and, possibly, ignition system.

Originally this was caused by the frustrations of trying to get the much-tweaked 1300 in my Herald to deliver the goods using SUs or even Webers and the thought has having an electronically adjustable system seemed attractive. Also I was hugely impressed by the grunt, tractability, economy and all-round good manners of our Golf GTI.

Trouble was, that was 15 years ago and I was far too mean (not to mention poor!) to shell out for a Weber Alpha or similar.

Now it's a different story. The excellent, build it yourself Megasquirt system has been on the scene a while now and the scrap yards are bulging with cars to supply the hardware. Should be possible to do it for pretty reasonable money.

This time the victim is my Vitesse MK 2. The aim is to achieve improved power, economy and manners over the original (and rather worn) carbs.If nothing else the choke knob will be made redundant.Oh, and do as much as possible myself and spend as little as possible on the way.The modifications should also be reversible.As I write this, the engine is standard, well worn (mileage unknown but considerable) but serviceable.Compressions and oil pressure are good, but it does like a pint now and again.


Tired old 2 litre lump.Bog standard and well thrashed in.


75A Bosch alternator


Fuel Pressure gauge (temporary)


Inlet air temperature sensor (beneath)


Cold idle valve




Fabricated manifold


Fuel Rail


Additional coolant temperature sensor for ECU


Fuel pressure regulator


Throttle body and position sensor



Well, as this is a car that was never made with fuel injection, there are quite a few modifications to be done.This involves quite a few systems and the work involved should not be underestimated.As high-pressure petrol and electricity are involved, this is safety critical work.

The picture above shows the under-bonnet modifications Ė click on the links below for more information.

Fabricated manifold

Fuel Rail


ECU and wiring

Fuel Pump


Exhaust Manifold


How Does it go

At time of writing (Autumn 05) itís a runner and has been since May.In fact it goes pretty well.There is room for improvement in the mapping as, so far, this has all been done on the road, solo using logging software.This particularly relates to the cold start areas and the upper reaches of the rev band at large throttle openings.I havenít touched the map since June and have done in excess of 2000 miles, so it canít be too far out!It starts, drives from cold (say 10ļ ambient, lower than this is untested!) smoothly.It pulls hard to 4500rpm at about 70% throttle, which is more than enough for everyday use.Above this itís more hesitant.The problem with mapping on the road is that you canít spend much time in this area for obvious reasons!It averages around 31 Ė 32 mpg in general use and 36 mpg on a long run.This is much more consistent than with carbs.It has been completely reliable.

Mapping will resume once the EDIS ignition system is installed and I may even cough up for a rolling road session!