MSA cutoff wiring on a common rail diesel

[vxpenfold]

Hi I'm currently building a vauxhall vectra diesel for competition next year and keep finding myself hitting a fair few walls, most I have sorted but unfortunately this one seems to be a difficult one for such a simple component

I'm trying to correctly wire in the cut off switch so it isolates and cuts the car out correctly, the battery is located in car so luckily the switch is only a foot from the battery and totally isolates the positive circuit nicely and as such the resistor wiring is also nice and easy the problem comes in the "number 2" connections, usually that would be on the coil or similar on a petrol or stop solenoid on an old diesel but I'm struggling to find the best method on my common rail diesel, my only current thought is to isolate the primer pump which would eventually cut the engine but would run on for a little while which I assume will cook the resistor etc and will probably not meet regulation.

Any help would be greatly appreciated

James

[RED21]

I would find the main after ignition supply to injection ECU and use that, any secondary supplies would be cut when the isolation switch cuts the battery.
Using the fuel pressure sensor or flow control solenoid wiring may create voltage drop problems (most use 5volts supply) or logs a fault that will put the vehicle in to limp mode when you don't want it.

[JimW]

What supply does the production "ignition" switch cut when you turn off the engine in a standard road version?

Try that.

Regards

Jim

[vxpenfold]

I had thought about the ecu power but didnt know if that could damage the ecu or not

Unfortunately the ignition switch is all integrated into the cim (column intergration module) which has all the stalk etc on it and is a standalone control unit so you don't have the traditional ignition and starter wires which is also causing issues with running a aircraft style ignition toggle and push button start, to do that will involve complicated electronics and a brain bigger than mine :/ I've tried myself and destroyed one module in the process.

Thanks for the help guys