Fuel Injection Control through OBD port?
OBD is a diagnostics output from your vehicle to give those who service it the state of the vehicle, diagnostic codes, reset options for errors and parts replacement initialization. 
This is as it only provides information from one of the layers of the CAN BUS. 

You can maybe send commands through to the ECU for the Injector but this WILL cause you problems down the line. There are many sources for hacking your cars CAN lines, but this is restricted from everyday people for obvious reasons, as you might mess something up. The other thing is that you would need to know the specific PID and information for controlling the Injector.



THIS IS A WAY TO DO IT BUT THIS IS AT THE END USERS RISK AND MAY VOID WARRENTIES AND SUCH POLICIES



IMPORTANT

Please insure that if you ever activate the system it is moving at a safe speed, i.e. don't do it at 120 kph you would be better off activating it while the car is moving at less than 20 kph (or 12mph). This will reduce risk of accidents. The original employer insures this using GPS based speed before activation.



You can monitor the speed of the vehicle by monitoring the speed on the OBDII port, using the PID 0D, this is the speed in kph, found on wikipedia under Mode 1.

Below is the basic implementation of the method that is used to control the fuel pump power. It is not the entire control circuit as it is copyright by the employer.







simulate this circuit &ndash; Schematic created using CircuitLab

The NPN type can be a BC337.


The system functions in that when your GSM module gets the command,
your MCU will activate the relay by making its GPIO high.

This removes the ground from the pump starving the engine from fuel
and thus not damaging the injectors(if its a diesel vehicle it will
really damage them... lots of cost to fix).

This way only starves the engine and thus stop it completely. This
does work and is proven by tests and permanent applications in the
field not to cause error messages.


This would be the safest way to do it as it will not cause your whole car to stop working by sending the incorrect commands on the BUS.