a REAL jake brake :)
 

ok i need some tech advice really bad, 1st off real engine brakes DO NOT EXIST for these trucks, 2nd they work by opening the exhaust valve kinda at the end of the compression stroke and killing fuel injection event, 3rd this is NOT done to all the cylinders and in my case just one

my idea is to put a hall sensor and a custom toothed wheel at the crank and have it trigger a solenoid or something to open the exhaust valve "just right" my question is how do i kill the injection event to the one cylinder exactly?????

I have no idea unless you can figuire away to to kill fuel by like a shut off in a injection line maybe.

Custom lines, high pressure solenoid (10,00 psi), hose back to tank. Activate the solenoid to dump fuel back to tank, it will take the path of least resistance and not crack the injector.