1. A fuel injection control system of the type electronically processing data indicative of a fuel quantity being injected into an internal combustion engine including an intake pipe and a throttle valve arranged in said intake pipe, in dependence upon parameters representative of operating condition of said engine, to obtain an electrical control signal corresponding to the value of processed data, and injecting a quantity of fuel determined by said electrical control signal into said engine, said system comprising: means for detecting a first parameter indicative of the rotational speed of said engine; means for detecting a second parameter indicative of the opening of said throttle valve; means for detecting a third parameter indicative of pressure in said intake pipe at a zone downstream of said throttle valve; means for detecting a fourth parameter indicative of the temperature of said engine; means for generating first data indicative of a basic fuel injection quantity, as a function of a combination of detected values of said first and second parameters; means for generating second data indicative of a basic fuel injection quantity, as a function of a combination of detected values of said first and third parameters; means for causing said second data generating means to generate said second basic fuel injection quantity data when an output value of said second parameter detecting means lies below a predetermined value, and causing said first data generating means to generate said first basic fuel injection quantity data when said output value lies above said predetermined value; means for generating a coefficient for correction of the value of said first or second basic fuel injection quantity data as a function of output of said fourth parameter detecting means; means for correcting the value of first or second basic fuel injection quantity data selectively generated by said first data generating means or said second data generating means, by an amount corresponding to a value of said correction coefficient generated by said correction coefficient generating means; means for generating said electrical control signal indicative of a desired fuel injection quantity corresponding to corrected data obtained by said correcting means; and means for setting the value of said correction coefficient to a value corresponding to a predetermined value of said fourth parameter which falls within a range within which the value of said fourth parameter can vary so long as said engine normally operates, when said fourth parameter detecting means generates an output value lying outside a range within which the output value of said fourth parameter detecting means can vary during normal operation of said engine.