When the vehicle is under acceleration it doesn't supply vacuum. The vacuum canister or reservoir holds a vacuum supply to operate vacuum operated accessories until the engine regains vacuum.
The vacuum hoses are very important in a 1991 Beretta. Without the vacuum lines, the engine will not run properly, and the power brakes will not function.
The engine does not produce enough vacuum to be usable.
The various functions are controlled by engine vacuum,defrost being the default without vacuum. Look far a damaged or loose vacuum line starting from the function switch,through the reservoir,to the engine vacuum port.
The engine is the vacuum pump. All the vacuum operated accessories are operated by the vacuum supplied from the engine.
A gasoline engine makes it's own vacuum. The diesel engine has a vacuum pump next to the power steering pump.A gasoline engine makes it's own vacuum. The diesel engine has a vacuum pump next to the power steering pump.
The engine does not produce enough vacuum to be usable
The engine itself creates Vacuum once it is running.
Assuming you mean "increases" in speed, as you accelerate the engine the HVAC (Heating Ventilation Air Conditioning) system is loosing its vacuum supply to function properly. Normally the system depends on a vacuum reservoir to maintain operation. This happens when the vacuum supply from the engine is leaking because of damaged/cracked/pinched vacuum lines. Inspect all the vacuum lines associated with the HVAC system.
You must have a diesel. The vacuum pump is what gives you POWER BRAKES and on the newer engines it also makes the power steering work. Only a gas engine makes vacuum. A diesel engine does not make vacuum, so they install a vacuum pump.
EGR stands for Exhaust Gas Recirculation. The purpose of the EGR system is to lower the amount of oxides of nitrogen the engine produces. The parts of the system are the vacuum actuated EGR control valve, the vacuum switching valve, and the EGR vacuum modulator assembly.
It operates only when the engine is turned over due to vacuum/suction from the engine .....If not working properly, there will be no electrical charge to the injectors.