All
automotive engines produce a type of toxic chemical known as nitrogen
oxide. Historically, most nitrogen oxide passed out of a car along
with the exhaust. Yet as emissions standards have grown stricter,
many new cars now include an exhaust gas recirculation system. This
system cycles exhaust back through the engine, thus reducing nitrogen
oxide levels.
The
key component in this system is the exhaust gas recirculation valve,
or EGR valve. Unfortunately, if your EGR ceases to work properly,
serious problems may ensue. If you would like to boost your
automotive knowledge, keep reading. This article outlines three
common causes of EGR valve problems.
1.
Faulty Temperature Sensor
As
discussed above, the most important goal of the exhaust gas
recirculation system involves reducing nitrogen oxide levels. Yet
your EGR valve also ensures ideal fuel efficiency by helping to
regulate the temperature and pressure inside of your engine
cylinders. To deliver the best results, your EGR valve only opens up
at certain key times.
In
order to know when to open and close, your EGR valve relies on the
information it receives from the EGR temperature sensor. As engine
temperatures rise, the EGR valve opens progressively wider to
compensate. Once engine temperatures have cooled, the EGR valve then
closes again.
A
common source of EGR failure doesn't actually involve the valve
itself. If the EGR temperature goes bad, or takes faulty reading as
the result of carbon build-up, your EGR valve will fail to perform
the way it should. In most cases, the EGR system flow will remain
insufficient, no matter how hot your engine becomes.
Fortunately,
you can usually restore normal operations by having your temperature
sensor inspected and replaced if necessary.
2.
Clogged EGR Pipe
Your
EGR system routes exhaust back to the engine through a dedicated
section of tubing, often referred to as the EGR pipe. The exhaust
flowing through the EGR pipe contains a large number of contaminants,
including soot. Over time, such substances tend to build up on the
walls of the EGR pipe. Eventually the deposits can grow thick enough
to interrupt flow altogether.
This
issue leads to the same set of problems as a faulty temperature
sensor. Namely, the EGR system will suffer from an insufficient flow
rate. As a result, engine temperatures often rise to dangerous
levels. Fortunately, an experienced mechanic can easily fix a clogged
EGR pipe.
The
solution involves detaching the EGR pipe and spraying the inside with
carburetor cleaner. This substance loosens up any deposits, which the
mechanic then scrubs free using a metal-bristled brush.
3.
Sticky EGR Valve
The
same contaminants that can clog up your EGR pipe also accumulate on
the valve itself. Over time, those substances make it more difficult
for the valve to open and close properly. The valve may even become
stuck in a partially open or partially closed position. As you can
imagine, both of these scenarios wreak havoc on the performance of
your EGR system.
An
EGR valve that sticks in the closed position will fail to allow any
exhaust into your engine. As a result, engine temperatures rise,
often resulting in knocking or pinging noises. An EGR valve that
becomes stuck in its open position allows too much exhaust into your
engine. This extra exhaust often causes the vehicle to idle more
roughly than usual or even stall out entirely.
In
some cases, a mechanic can fix the issue simply by cleaning any
deposits off of your EGR valve. If the build-up has led to mechanical
damage, however, you may need to have an entirely new EGR valve
installed.
The
EGR valve plays a key role in both emissions control and engine
performance. For more information about the state of your EGR
valve, contact us
at Dualtone.
