A faulty fuel regulator, which may not be regulating the pressure of the going to the engine as it should.A leaking fuel injector allowing too much fuel to enter the combustion chamber.A dirty mass air flow sensor overstating the amount of air entering the engine which may cause excessive fuel delivery.
The term “rich” in this case means that there is too much gasoline and not enough oxygen detected in the air-fuel ratio of the engine. However, if the margin of compensation is too large, then a P0172 code will likely set. The ECU has the ability to slightly adjust the air-fuel ratio if it is rich. This particular ratio was chosen because it was discovered to have the highest power output but lowest fuel consumption rate. The best air-fuel ratio modernly known to man is 14.7:1. Most routinely, the air-fuel ratio will be measured through the oxygen sensors calculating the amount of oxygen and carbon monoxide present in exhaust gases. The ECU uses a number of instruments, such as the mass air flow sensor (MAF), oxygen sensors, and manifold absolute pressure (MAP) to monitor the air-fuel ratio of the engine. P0172 indicates that there is too much gasoline being detected in the exhaust gases exiting the combustion chamber.
P0172 is a trouble code that is set when the ECU senses that there may be too much gasoline present in the air-fuel mixture of the engine.Ī proper air-fuel ratio of about 14.7:1 is vital to obtain maximum engine power and fuel economy.