Last Updated 19 April 2001
Before I start, let me make it clear. You should not perform ANY of the operations described here unless you have access to full electronic workshop equipment, and an antistatic workstation. The servicing af an ECU by an unqualified person may lead to its destruction, resulting in you forking out several hundred pounds for a new ECU, and that's assuming you can get one.
The Lotus Carlton uses the Delco (now called Delphi Automotive) GMP4 ECU, part number 01228331, to control its engine. This unit is also used in the American Corvette with the LT5 engine option, although the program in the MEMCAL is completly different in that application. In the LC, the ECU is mounted in the passenger side footwell, behind the glove box. To gain access to the ECU, you must first remove the golvebox, and some of the heater ducting. You should then see the ECU. To remove it, you need to undo the four nuts (2 each side) that hold it to the mounting bracket, and unplug the 4 connectors on its top. You do not need to remove the ECU in order to change the MEMCAL though. Below are a some photos of my ECU.
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The ECU is housed in a weatherproof box, and all the connectors and openings are sealed with rubber gaskets. The light grey panel in the lid of the box covers an opening allowing the MEMCAL to be inserted and removed. The photos above are of my spare ECU. An original LC ECU has tamperproof stickers applied to the MEMCAL cover stating 'warantee void if these stickers are damaged'. This is to prevent unauthorised changing of the MEMCAL, such as when the cars are 'chipped' to make them 'go faster'. Therefore, you should be able to tell if your car has even been chipped by looking to make sure these stickers are present and undamaged. When the MEMCAL panel is removed, you can gain access to the MEMCAL itself, as shown in the second photo.