Question : MY 2003 Proton Wira 1.3 has approximately
80,000km on the clock.
The problem I am facing is that the engine
check indicator lights up intermittently after
the vehicle has been driven 8-10km.
The vehicle had been sent to my regular
mechanic several times. On each occasion, he
merely sprayed the air intake with some kind
of solvent and charged me sixty dollars.
Apparently, my friends are facing the same
problem and we hope that you can help with
THE problem that you and your friends are facing seems to revolve around the air inlet.
Either the air mass flow sensor or the inlet air temperature sensor could
be acting up. Both are essential for the electronic fuel injection system to
function properly since the rate of air (measured by mass) flowing into the engine deter-
mines how much fuel is to be injected.
Unfortunately, there are no fixed service lives
for both pieces of equipment and they are liable
to failure at any time.
The air mass flow sensor is a particularly sensitive piece of equipment. The latest types utilise a
hot wire. A fine wire is kept at a high temperature
so it emits ions to the surround of the flow meter.
The amount of ions collected by the surround of
the flow meter is a measure of the rate of airflow.
Often, modifications by car owners seeking
better performance include the use of a free-flow air-filter that has an oiled element. The oil
collects on the hot wire, rendering it useless, and
the Engine Control Unit (ECU) is fooled into
thinking that the flow meter has failed. The
same goes for the temperature sensor.
What your mechanic has been doing is cleaning the sensor but, obviously, the solution works
for a while but as long as the original cause is
not identified and fixed, the problem will return.
Of course, other problems could include a
leaking intake system that allows dirt to collect
on the above components.
Poor wiring could also result in similar problems and the best thing to do is to have the
vehicle hooked up onto a dedicated diagnostic
machine that would pin-point exactly which
component is at fault.