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EVAP SYSTEMS
: Checking for leaks in evaporative emission sys-
tems is simple. Start by pressurizing the EVAP system (do not
exceed the recommended pressure). Now, sweep all the hoses and
components of the system and listen for a hissing noise that would
indicate a leak. Once the general area of the leak has been
determined, move closer with the receiver to pinpoint the exact
leakage source.
Use the hollow air probe or use the receiver
alone
.
INJECTORS:
Place the solid contact probe onto the injector to test
and listen while the engine is running. You can hear the injector
working plus hear the fuel flow. You may also want to shut off the
engine and listen to make sure that the injector is not leaking fuel
past the injector nozzles. If fuel is flowing, it will create a rushing
noise in the headset. A good clean injector will make a sharp
ringing clicking tone, while a dirty injector will have a muffled
clicking tone.
Use the solid contact probe.
AIR BRAKE SYSTEMS
: The Marksman II can help locate leaks
quickly in both vacuum assisted and air brake systems. In many
cases, leaks can be detected from a considerable distance. After
building up full pressure (in the case of air brakes), a casual sweep
of the vehicle from one end to the other using the receiver can often
locate the leak. Use of the headphones will reduce noise
interference from the shop. If the first sweep does not locate the
leak, trace out the entire air system piping at close range (1-2 feet
or 0.3-0.6 m) with the receiver. Once the general area of the leak
has been determined, the receiver probe is very useful to pinpoint
its exact location. For maximum effectiveness, be sure that
pressure is maintained in the brake system during the entire
search. If no leaks are discovered, check the air horn, windshield
wiper and other air-actuated equipment. Leaks in these accessories
can produce an abnormal gauge drop.
Use the hollow air probe or
use the receiver alone
.
