GxT Ferret 21 Smoke - Manual (Page 8)

8 www.ferretinstruments.com
System Checks
EGR Valves
One of the most common uses for CoolSmoke is detecting vacuum, or exhaust leaks in and around EGR
Valves. Frequently a drive ability or emissions related problem (especially NOx related) may be caused
by an inoperative EGR Valve (defective diaphragm, leaking solenoid, leaking vacuum line). By applying
CoolSmoke to the diagnosis, a visual result will be seen quickly.
It’s also possible to fi ll the exhaust system from the tailpipe forward to reveal EGR related leaks. You will
locate any exhaust leaks at the same time. For true dual exhaust, treat each branch separately. If the
branches are joined, plug one of the tailpipe outlets.
Fuel Injectors
A port fuel vehicle that has been overheated, may have hardened or broken ‘O’ rings around one or more
injectors. Inserting fog into the intake manifold (plenum) will easily point out this condition out. Some
intake and exhaust valves will be open, so fog may eventually appear at the exhaust, and potentially at
or around the throttle body area.
Base Gaskets
Fog introduced into the intake manifold at virtually any point will fi ll the area and fi nd a way out if it is
available. A carburetor or throttle body base gasket that is leaking will be easy to spot quickly. In some
cases (when a supplied adapter is not suitable), it will be worthwhile to remove the air cleaner and seal
the air intake with a plastic bag (or similar) and a couple of turns of tape.
Air Intake with a Mass Air Flow Sensor
As many Port Fueled vehicles age, a leak between the Mass Airfl ow Sensor and the Throttle Plate/Body
can occur. This could be the result of degenerating air intake material, or as simple as a clamp that
has lost adjustment / tension and no longer seals. This condition allows unmeasured oxygen into the
intake, which leans out the air / fuel ratio while lowering the average oxygen sensor readings. The natural
tendency is for the on-board computer to add additional fuel. Over time, this situation will eventually lead
to a failed catalytic converter.
With the engine off, fi ll the intake manifold with fog. As the manifold fi lls, fog will migrate past the throttle
plate and into the intake ducting between the throttle body and the air cleaner. Carefully observe any
leaking fog. Any leaks between the Airfl ow Sensor and the throttle body/plate are false air leaks.
Vacuum Lines/Intake Manifold or Plenum
The most ideal manner to check an intake manifold is to go in through the fuel pressure regulator vacuum
hose, if it’s available. The PCV Hose or main power brake booster hose can be used as well. Remove
the hose at the regulator and use the large clear hose to adapt. Fill the manifold with fog, after about 30
seconds, any fog you observe in the engine compartment must be investigated. Pay particular attention
under the plenum if possible. Suspected leak at a vacuum line or any vacuum controlled device can be
easily spotted once the system is fi lled with fog.
Never assume there is only one leak. Vacuum lines or devices that are controlled by a solenoid or
temperature valve should be treated individually.