This is the circuit I made. I ran a wire off the pump side of the over pressure switch. This wire runs to a pressure switch by the nozzle with an inline dash light. When the nozzle sees 35psi+ fluid pressure the pressure switch turns on the light. If not enough pressure, the light doesn't turn on.

So if there is too much pressure, the pump shuts off and so does the light.

Then I have a relay inline this circuit, that activates the idle switch pin. This switches to Aux maps.

So when egr turns on water injection. The fail safe wire activates the dash light and the aux map.

So if nozzle clogs. Light goes out.. Switches to base map..

Hose comes undone.. Light goes out Switches to base map

Run tank empty.. Light goes out Switches to base map.



So far it works well.. But I stripped the threads in my check valve so it's on hold till spring. I was running 7g nozzle .. 5 parts water 2 parts meth. Didn't seem to effect the a/f but dropped temps everywhere and eliminated knock at 25psi and 14°timing.