Abstract: According to this process, the computer determines opening time (Ti) of the injector from a nominal time (Tin) as a function of the parameters of the engine operation and of a proportional and integral correction term (.alpha. cl) as a function of the state of the signal of probe .lambda.. More particularly, a richness predictive estimate (Re) of the exhaust gases is made from the engine operating parameters and from pure delay (m), determined experimentally, between injector (2) and probe (12), at least a simulated probe signal (Ss .lambda.) is produced from said richness predictive estimate, said correction term (.alpha. cl) is produced from simulated probe signal (Ss .lambda.) and said correction term (.alpha. cl) is modified periodically in response to the detection of a difference between the state of measured probe signal (S .lambda.) and the state of a delayed simulated probe signal (S"s .lambda.). Application to vehicles with internal combustion engines.