Here at JGS4x4, we get asked, almost daily “Which is the best TD5 air mass or airflow meter?”
The Land Rover TD5 engine as fitted to Discovery 2 and Defender models can suffer from a lack of power, particularly at lower engine speeds, symptoms feel like turbo lag with the engine feeling gutless at lower speeds.
This can be caused by a faulty or failed airflow meter. The airflow meter is also known as an air mass meter or MAF. The airflow meter is located in the air inlet pipe, downstream of the air filter and measures the volume of air entering the engine. The car’s brain or ECU uses this measurement along with values from several other engine sensors to control the amount of fuel injected into the cylinders. The airflow meter is a very sensitive and delicate piece of equipment.
Replacing the MAF or airflow meter can restore power back to how it should be.
Symptoms of a faulty air flow meter include:
- Rough, uneven idling
- Black smoke
- Poor performance and economy
- General poor running
How to test your Land Rover TD5 airflow meter
There are several ways to test the airflow meter is functioning correctly. If you have a fault code reader, such as the Hawkeye, Lynx Evo or IID Tool you can check for any stored faults and also check the live values to see if the measured airflow changes when the car is revved up. The airflow is normally shown as a measurement of grams or Kg per second and should increase as the engine speed increases.
You can also disconnect the airflow meter if it makes no difference the sensor is faulty. The ECU will use a default value when the sensor is disconnected.
Or you can test with a very basic multimeter!. Measure the voltage output from Pin2 to earth or ground, a working airflow meter should have around 2 volts+ output when the engine is at idling speed which is approximately 60kg/hr of air. If you do not measure within a small amount of 2 volts output, then airflow meter could be faulty or totally failed and needs replacing.
Replacing a Land Rover TD5 airflow meter
The airflow meter is very easy to replace, the wiring simply unclips from the sensor body and a screwdriver is needed to loosen the hose clamp and the screw holding it to the air filter box.
There are various brands on the market, ranging greatly in price. Here at JGS4x4 would always recommend spending a little more for peace of mind and reliability on a Genuine OEM airflow sensor from Siemens VDO, see MHK100620.
Whichever model of Land Rover you own, whether it is a Freelander, Defender, Discovery or Range Rover, JGS4x4 has a large range of parts and accessories for maintaining, servicing and personalising your Land Rover, available for worldwide delivery on the JGS4x4 website.