There was a frequency valve that basically allowed more or less air to enter the intake…it was an emissions adaption. There was also a warmup regulator but nothing really electronic brain level. Just bimetallic springs or contact switches. Some did have an o2 sensor and a rudimentary computer...
The only mechanical fuel injection system I know of or am at least familiar with is Bosch KJET. It uses a high pressure fuel pump mounted in the tank and fuel metering distributor that feeds mechanical fuel injectors. The entire system works off of fuel pressure and a seesaw like mechanism in...