into the cylinders. This volume of vented air is no longer relevant to the engine, however it is still included in the calculations for the required amount of fuel, which causes excess fuel to be injected and therefore the engine briefly operates with a fuel-rich mixture after each blowoff valve actuation. Effects of this rich running can include fouling the spark plugs, damaging the catalytic converter, stalling and hesitation when the throttle is opened. One method to avoid this issue is by locating the airflow sensor downstream of the blowoff valve (known as a blow-through setup, as opposed to the traditional draw-through setup). By using a blow-through method, the MAF won't be affected by the blowoff valve opening, since the pressure is vented before the air reaches the MAF. Other solutions include using a blowoff valve that recirculates the air back into the intake or using a manifold absolute pressure sensor (instead of an airflow sensor) to determine the amount of fuel required. See also Wastegate Relief valve Water hammer References Further reading Allard, Alan. Turbocharging and Supercharging. Cambridge, England: Patrick Stevens Limited, 1982. Gorla, Rama, and Khan, Aijaz. Turbomachinery Design and Theory. New York, New York: Marcel Dekker, 2003. Society of Automotive Engineers. Turbochargers and Turbocharged Engines. Warrendale, PA, 1979. Watson, N, and Janota, N. Turbocharging the Internal Combustion Engine. London, England: Macmillan Press Ltd, 1982. Engine valves Turbochargers de:Turbolader#Umluftventil