Enhanced Megasquirt and the clutch switch override
 

Something I just realized. People use the FM clutch switch override so they don't have to press on the clutch to start their car.

The Enhanced MS2 that I build actually uses the clutch switch to determine whether the ECU should enter idling mode ("CL Idle") or not. With the clutch switch always pressed in, the ECU is tricked and this may result in a high idle, anything from 1500 up to 4000rpm, after you coast down to a stop.

If you have the problem described above, you need to remove the clutch switch override. Alternate solutions are:

- Wire in a momentary switch that grounds the clutch switch input wire to a ground. You need to press the momentary switch while cranking to enable the starter.
- Wire in a relay to the ignition, so the relay is activated in the "START" position. When the relay is activated, it grounds the clutch switch input wire, thus enabling the starter.

Dimitris

No, this is not a problem, as there are actually two separate clutch switches.

At the bottom of travel, mounted to the firewall, is a high-current switch used only to interrupt the starter. This switch is actuated only when the pedal is depressed fully, and is the switch which FM's little clip over-rides.

At the top of the travel, mounted to the bracket which contains the clutch lever's pivoting hinge, is a smaller switch which is wired to the ECU. This switch is actuated when the pedal is depressed only partially, and has no relation to the starter.