1997 Mitsubishi Galant will not start

This video may help ... the sensor is underneath the timing belt cover so it is a bit involved to get to ....
https://www.youtube.com/watch?v=RHMe3S7RQ68

Follow the link for instructions, and yes 2003 is the same.

Have you changed Fuel pump relay, or plugs/wires?

Yes your 4 cyl engine uses direct spark with a coil over each spark plug.
And the computer controls the firing of the plugs and injector pulse.
The problem could be the crank or cam sensor, or the wiring harness, but in most cases the check engine light should be on and a code set.
You might want to check the computer for codes, then try the cam sensor.

can you move it by hand?what noise do you hear when trying to start.
is the gear from the starter full in the motor.are all wires connected.

you now need to check for 12 volt power, and signal to the coil, also be sure all you timing marks are correct, if you have no spark, unplug one of the injectors and using an led test light check for injector pulse power across the two terninals while cranking, if you have no injector pulse then you could have a problem with the ignition passlock system, or key decoder

You need three things to run: spark, fuel, compression (timing). Check for spark simple, check for fuel (crank over engine and pull spark plugs, is fuel on them? ) if not rent noid lights from Autozone or such to check upon injector pulse. If nothing let me know and we'll look further in to it.

Best regards,
Tom

could be the crank sensor, you need to check spark and fuel delivery, if you have fuel then its got to be the high tension side of things that are wrong, does this model run off a coil pack for the ht, could be that, you said you change the alternator, check connections at the rear of alternator, this could be the supply for the ht etc,good luck.

you need to start with the basics and find if you have fuel, spark. when the no start problem is occuring.

its a very common fault with the GDi engine, normally first shows a fault after 60k miles. Fault will also make the engine feel slightly juddery on occasions whilst cruising... either/both Accelerator body or Cam sensor are the usual culprit. Both can be rather expensive.