Much like a traditional carburettored engines choke, the ME ECU range allows a modifier to the fuelling to be carried out in order to enrich the mixture when the engine is cold, or in a state of ‘warm up’. Note that this is different to the cranking fuel, and After Start Enrichment (ASE is a quick over-rich state that happens for the first few seconds.)


The Fuel CLT Trim Table allows you to enrich the mixture based on the reported coolant temperature. Be sure to have your coolant sensors HRT/Calibration correct (see calibrating coolant sensors). The final fuelling pulse width is multiplied by this tables output (shown in the ‘Environment>Fuel CLT Mod’ digital readout). Note that above 70*C in the table shown above, the output is ‘1.0’, or in other words, no longer modified. It would also explain why you should only tune the VE of a warmed engine - otherwise you have corrections fighting you!


The ECU also provides a coolant based ignition trim table, should you wish to add advance to a cold engine, to increase engine speed without the use of any form of idle control. Normally however, this would be left at 1.00 across the whole table.


In terms of tuning, again, only attempt this after VE has been properly tuned, it is simply a case of targeting your prefered idle mixture (or slightly richer) through all stages of the engine warming up. Adjust this table in real time as the yellow cross hairs ‘walk’ along it as the engine warms.