Manifold Absolute Pressure Sensor - MAP Sensor
The MAP or manifold absolute pressure sensor is used in a fuel injected motor to monitor the manifold pressure at all times of engine operation. The MAP sensor transmits data to the Engine Control Unit - ECM for optimum engine performance. This manifold absolute pressure sensor is just one of the many different sensors used in today's modern diesel engines.
The MAP or Manifold Absolute Pressure sensor has 5-volt reference and ground inputs and in turn, outputs a voltage signal between 0 and 5 volts depending on the pressure it senses. This sensor is responsible for measuring the pressure in the intake manifold about atmospheric pressure. When the pressure it senses is lower than atmospheric pressure (vacuum), the sensor will output a lower voltage. As the pressure it senses rises to match atmospheric pressure (vacuum drops), the voltage output of this sensor rises. This sensor also doubles as a barometric pressure sensor. When you turn the key on before starting the engine, the ECM takes the reading from the MAP sensor and uses that to calculate barometric pressure. The ECM uses barometric pressure as the basis for calculating fuel and spark delivery to the engine.
Diesel engines use the MAP sensor as an aid to control of fuel injection precisely for the best engine performance possible based on the current conditions. The MAP Sensor or Manifold Absolute Pressure Senor continuously monitors the air intake system pressure readingsThe manifold absolute pressure sensor transmits data which is used to calculate:
- Air density
- Mass Air Flow Rate
- Optimum combustion
- Advanced or Retarding Injection Timing
Below is a list of warning signs associated with a failed MAP Sensor:
- Poor engine performance by getting the incorrect amount of fuel to the engine
- Dark black exhaust smoke
- Decrease level of turbo boost
- Poor Engine Performance
- Incorrect Air Fuel Mixture
- Improper Boost Pressure
- Turbo lag
The MAP Sensor needs to be kept clean for proper operation:
Your manifold absolute pressure MAP sensor is positioned downstream of exhaust-laced intake air but they are not immune from problems, either. Once they’re caked full of grime and soot, it can skew the information sent to the truck’s ECU, which can negatively affect engine performance and fuel economy. It’s good practice to clean your truck’s MAP sensor periodically to keep it in ideal working order.
Please see the other Automotive Engine Sensors offered by KLM Performance inc.