no start no crank and no crank when i bypass the starter relay switch 2001 tahoe - i know another thread but i cant find my help

[efraser]

continuing this hard question.
i installed a momentary engine push start button, just sitting in the engine bay for a back up in case of this problem happens again.
i pressed the button and car turns over, turn the key to the where it is right before starting. i turn the key and all it does it turn over and will not start the engine, did this a few more times and can smell fuel but will not start.
go inside and turn the key over and it starts right up

so why will the push button not start the vehicle as it is bypassing everything