My Land Rover Freelander TD4 is suffering from a lack of power. I’ve recently renewed all the filters (including fuel and air), and have carried out an engine oil change.
The mechanic says...
First take a close look at all the vacuum hoses around the engine; these can chafe/perish in time and their failure will cause a loss of power.
If all seems well with the hoses, the Mass Air Flow (MAF) meter could be failing; this is a common problem on this engine, and will give the symptoms described. This ‘mass meter’ is a delicate component that can begin to degrade with time. In the early stages of failure there may be very subtle negative effects on engine fuelling. Peak power can start to fall away very slowly, in most cases initially not noticeable by the driver.
In some cases the vehicle can be completely undriveable from cold, until normal operating temperature has been reached by running the motor.
Note that unless there is an electrical circuit problem, it is unlikely that an electronic diagnostic assessment will reveal a specific stored ‘trouble code’ relating to failure of the mass meter. Accurate testing of the meter is difficult since there may only be very small differentiations in measured voltage between a good unit, and one that has failed.
It’s also worth noting that any running problems caused by mechanical faults with the engine can seriously affect the performance of the air flow meter.
Installing a new meter can be accomplished in under half an hour and the cost should be reasonable. When changing the mass meter, the air filter should also be renewed at the same time, using a good quality replacement. Specialists advise that although on these engines the original Bosch air flow meter is often replaced by a cheaper ‘after market’ alternative, there is considerably less chance of trouble if an original Bosch unit is used.
