This content originally published at our WWWedge site, on the Wedgelabs page(s) developed by Gene Thompson, and hosted at team.net. Gene Thompson retains all copyright for the material below, except where noted.
The Lucas 4CU ECU in fuel injected TR8s, Rover SD1s and euro Range Rovers has a pretty bad reputation. Well, OK - a really bad reputation. But the dirty little secret is that the vast majority of ECU failures can be remedied in a few minutes with no need to send it away to have it expensively 'rebuilt'. With a little care, common sense and this guide you can probably do it yourself - but you don't have to, as the TWOA will repair and test your TR8 ECU for members, for the cost of shipping (both ways). With the money you save, you can buy some decent tools.
Click image to open file (adobe pdf)
The PDF on the left has complete schematics and circuit board layout diagrams along with numerous other charts and graphs. I included a few repair tips and some simple performance modifications. Combine those simple mods with a rising rate fuel pressure regulator and you're in business without hacking the EFI system to bits!
Click on the picture at the left to open the pdf file which has extensive details on the operation, troubleshooting and repair of the ECU.