Control Pressure Regulator
The control pressure regulator (or warm-up regulator) controls fuel pressure to the top of the plunger in the fuel distributor. See Fig 1 .
During cold start operation, reduced pressure allows the plate to open farther with same air flow. This supplies more fuel to the cylinders to improve engine warm up, until normal operating temperature is reached. As the engine reaches operating temperature (or a pre-determined time elapses), the control pressure regulator increases control pressure, leaning the air/fuel mixture.
A bi-metallic strip in the control pressure regulator is heated by an electric coil. As it heats up, it gradually increases the control pressure. Poor electrical connections will cause warm-up function of the regulator to cease operation. Some regulators have an altitude-sensitive function that compensates for changes in barometric pressure.