See Figures 1 and 2
The EFE system is used on some of the engines to provide a source of rapid engine heat up during cold operations. It helps reduce the time that carburetor choking is required and helps reduce exhaust emissions.
There are two types of EFE systems. The vacuum servo type, consists of a valve located in the exhaust manifold, an actuator and a Thermal Vacuum Switch (TVS). The electrical type, consists of a ceramic grid located under the base of the carburetor.
A check of the operation should be made at regular maintenance intervals.
Vacuum Servo Type
- With the engine cold, observe the position of the actuator arm. Start the engine. The arm should move toward the diaphragm (closing the valve).
- If the arm does not move, remove the hose and check for vacuum. If still no vacuum, remove the top hose from the TVS switch and check for vacuum.
- If vacuum is present in the top hose, replace the TVS switch.
- If vacuum is present at the actuator and it does not move, try to free the valve. If the valve cannot be freed, it must be replaced.
Turn the ignition
with the engine cold and probe both terminals of the heater switch connector with a test light.
If 1 wire has power, replace the heater switch.
- If power exists at the pink wire, disconnect the heater connector and connect a tester across the harness terminal. If no power, repair the ground wire; if power exists, check the resistance of the heater.
- If heater is over 3 ohms, replace the heater. If under 3 ohms, replace the connector, start the engine (operate to normal temperature) and probe the pink wire. If no power, the system is OK; if power exists, replace the heater switch.
REMOVAL & INSTALLATION
Vacuum Servo Type
- Disconnect the vacuum hose at the EFE.
- Remove exhaust pipe to manifold nuts.
- Remove the crossover pipe. Complete removal is not always necessary.
- Remove the EFE valve.
- Position the EFE valve into place.
- Install the crossover pipe.
- Install the exhaust pipe to manifold nuts.
- Connect the vacuum hose at the EFE.