Their purpose and fuction


MAF Sensor (Mass Air Flow)
A mass air flow sensor is used to find out the volume of air entering the engines cylinder. The air mass information is necessary for the (E.C.U.) to balance and deliver the correct fuel quantity to the engine. The sensor also incorporates an intake air temperature (I.A.T.)

MAP Sensor (Mass Absolute Pressure)
The MAP sensor is used as an alternative to the MAF sensor provides instantaneous manifold pressure information to the engine's (ECU). The data is used to calculate air density and determine the engine's air mass flow rate, which in turn determines the required fuel delivery quantity.

Boost Pressure Sensor
Serves a similar purpose to the MAF sensor. Sensing a rise in intake air pressure increase inside the inlet manifold from turbocharger boost.

Crankshaft Sensor
Used to measure the position of the crankshaft in combination with the camshaft sensor. The reference mark signal indicates the position of the crankshaft before T.D.C. on No.1 cylinder. A large tooth space on the ring gear makes it possible to determine speed and an accurate timing reference mark.

E.C.U. (Engine Control Unit)
Reads a multitude of sensors evaluates the physical variable readings obtained and adjusts the actuators accordingly.

Fuel Temperature sensor
A sensor built into the fuel pump control unit E.D.C (Electronic Diesel Control). Evaluated along with the engine temperature sensor, to adjust fuel delivery quantity

Rail Pressure Sensor                                                                                          Accurately and continuously measures the rail pressure, information is sent to the ECU. A voltage of 5v is applied to the senor. Changes in pressure within the rail will give a feedback voltage to the E.C.U. of between 0.5...4.5v. dependant on engine demand. 

Throttle Position sensor                                                                                          The pedal incorporates a potentiometer, as the position of the potentiometer brush changes so to does the voltage signal. This signal is the means of detecting the conditions of the engine such as Idle, Part load, Acceleration and Full throttle.

Water Temperature Sensor
The readings from this sensor are then fed back to the (ECU). This data from the sensor is then used to adjust the fuel Injection timing and fuel quantity delivered. The coolant temperature sensor works using resistance. As temperature subjected to the sensor increases the internal resistance changes. Depending on the type of sensor the resistance will either increase or decrease.





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28.05 | 12:42

Hi , have a Toyota 2ct kit from 1991 2.0 townace, the rectangular top body gasket is leaking , can I replace this in situ maybe !? Cheers Darren

20.05 | 13:47

Can you help me with a rough guide how to time the diesel pump on my talbot express 1300d motorhome it’s got a 2.5td engine

15.05 | 04:56 sheet on bosch injector pump, distribution head o ring replacement, I need torque NM for distributor head bolts, VE 300tdi land rover,thanks Warren

10.05 | 10:03

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