Equus 3660 - Hand Vacuum Pump & Brake Bleeding Kit - Manual (Page 12)

10 3660
1. Inspect the PCV system for worn, kinked or plugged hoses. Make
sure all hoses are properly and securely connected.
2. Connect the hand vacuum pump to an intake manifold vacuum
port. (use the hose and a suitable adapter from the accessory kit,
as needed).
3. Start and run the engine until it reaches normal operating
temperature.
4. Run the engine at idle and observe the vacuum gauge.
• The vacuum gauge should indicate between 16 ~ 22 in. (41 ~
56 cm) Hg.
• The gauge needle should remain steady (little or no movement).
• Note the engine speed (RPM) and vacuum at idle.
5. Clamp the vacuum supply hose to the PCV valve.
• Engine speed should decrease by approximately 100 RPM (as a
result of loss of air flow from the PCV system).
• Vacuum should increase slightly (indicating vacuum flow
through the PCV system has been plugged).
• If BOTH a decrease in engine RPM and an increase in vacuum
are not observed, replace the PCV valve and/or any damaged
or plugged hoses.
NOTE: Be sure to install the correct PCV valve for your vehicle.
Installing the wrong PCV valve can result in either excessive or
insufficient air flow through the PCV system.
5. After replacing the PCV valve, ALWAYS readjust the engine's idle
speed and, if possible, the idle air/fuel mixture. Refer to your
vehicle's service manual for procedures.
NOTE: On some vehicles idle speed and air/fuel mixture are not
adjustable. The on-board computer makes adjustments based on
sensor inputs and engine operating conditions. ALWAYS consult
the vehicle's service manual before making any adjustments.
VIII. TESTING THE EGR SYSTEM
A. SYSTEM OPERATION
The Exhaust Gas Recirculation (EGR) system is used to reduce Oxides
of Nitrogen (NOx) emissions. NOx is created when nitrogen and oxygen
in the atmosphere mix at temperatures above 2,500F° (1371° C).
During combustion, temperatures in the cylinders can exceed 3,500 F°
(1927° C), providing ideal conditions for the formation of NOx.
The EGR system reduces the formation of NOx by lowering the
combustion temperature. This is accomplished by recirculating exhaust
gases through an EGR valve back into the combustion chambers.