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Cummins Engine – Actuator Installation in an EFC Fuel Pump Housing

Oct. 18, 2019

In the previous article, we talk about Cummins engine electric fuel control governor, this article will turn to introduce Cummins generator engine actuator.

Actuator Description

The actuator is an electromagnetic rotary solenoid valve. The actuator is installed in the EFC cavity of the PT fuel pump. The actuator controls the engine speed and horsepower by controlling the fuel flow to the injectors.


The actuator shaft will turn when the current from the governor control changes.

actuator shaft.jpg

The current from the governor control will change when the magnetic pickup senses a change in the engine speed.

Cummins actuator.jpg

Fuel Flow Through the Fuel Pump

The throttle shaft is set in the full open position. The fuel flows through the fuel pump to the actuator (EFC) cavity.

fuel flow.jpg

The actuator controls the fuel flow to the injectors. The fuel flows through the actuator to the shutoff valve.

shutoff valve.jpg

Actuator Identification
Two styles of the actuator are now available.
a. Normally open
b. Normally closed

actuator styles.jpg

The normally open actuator is in the full fuel position when the electrical system is turned off.

open actuator.jpg

The normally closed actuator will stop the fuel flow when the electrical system is turned off.

closed actuator.jpg

The actuators are available in low, high, and ultra high flow.

Cummins generator.jpg

The actuators are rated at 12 or 24 volts D.C.

Make sure the governor control voltage is the same as the actuator voltage rating.

source voltage.jpg

EFC Fuel Pump Housing

When a new EFC fuel pump is built at Cummins, the pump will have an EFC housing.

The EFC fuel pump housing can be identified in the following areas:

The AFC no-air adjusting screw hole has been omitted.

fuel pump housing.jpg

The ASA or AFC vent hole, in the top of the housing has been omitted.

The AFC spring seat groove is not machined. A 45 chamfer is at the EFC actuator mounting surface.


Actuator Removal From an EFC Fuel Pump Housing

Remove the actuator wires and capscrews.

Caution: Do not pry the actuator from the housing. This can damage the actuator shaft and make it stick.

actuator removal.jpg

Twist tho actuator and pull it from the housing. Remove the three O-rings from the actuator.

twist the actuator.jpg

Actuator Installation in an EFC Fuel Pump Housing

Install a new O-ring on the 50 mm [2 in] diameter of the actuator. Install two new O-rings on the actuator barrel.

actuator installation.jpg

Apply the actuator rated battery voltage across the two terminals on the actuator to test the solenoid and to observe actuator operation.The actuator will make a loud click when the actuator shaft hits the internal stop. Removing the voltage from the actuator terminals will allow the force of the springs to return the actuator shaft to its original position. A click must be heard when the voltage is removed.

NOTE: The EFC housing does not require the EFC plug in the bottom of the EFC housing bore.

EFC housing.jpg

Lubricate the two barrel O-rings with clean engine oil. Insert the actuator in the fuel pump housing. The actuator flange will be approximately 3/8 inch [9.5 mm] from the pump housing.

barrel o-rings.jpg

Use the palm of the hand. Firmly push and rotate the actuator approximately 30 degrees until the actuator flange contacts the fuel pump housing. Rotate the actuator until the mounting holes are aligned.

fuel pump housing.jpg

Install the three 1/4-20 x 1 1/4 inch hex head capscrews. These capscrews have captive spring washers and do not require lock-washers. Tighten the capscrews until they are finger tight.

install capscrews.jpg

The actuator capscrews must be tightened in the following sequence:

1. Tighten the mounting capscrews 1/8 of a turn, in the sequence shown in the figure, until they are seated.

tighten the capscrew.jpg

2. Tighten the capscrews in sequence to 25 in-lb [2.8 N*m] torque.

tighten the capscrew.jpg

3.Tighten the capscrews in sequence to a torque in-lb. [5.6 N*m].

Cummins engine.jpg

4. Loosen all three capscrews completely.

loosen capscrew.jpg

5. Tighten the capscrews again in sequence to 25 in-lb. [2.8 N*m] torque.

6. Tighten the capscrews again in sequence to 50 in.lb. [5.6 N*m] torque.

7. This procedure will make sure that the actuator is properly installed and is not binding.

A final check is to apply and remove battery voltage across the two actuator terminals. The operation of the actuator must have a similar sound as it did before installing in the fuel pump housing. If the actuator does not click, as if it is not operating, or operating slower than before, loosen all of the capscrews and tighten them again as described in the previous procedure.

Caution: This test will only verify that the actuator will go from the full open to the full closed position. A slight binding of the actuator shaft can cause a governor stability  complaint. This test may not detect a slight binding.

battery voltage.jpg

The fuel pump can now be calibrated (Refer to the Fuel Pump Calibration Manuals or the monthly Cumulative Supplement Update).

NOTE: Apply the actuator rated battery voltage to the normally closed actuator when the fuel pump is calibrated.

Cummins generator fuel pump.jpg

The throttle shaft must be locked in the full open position. After the calibration, the fuel pump can be mounted on engine.

throttle shaft.jpg

Actuator Installation in an AFC Fuel Pump Housing

Remove the fuel pump if it is on the engine.

Remove the ASA, if required, and the AFC fuel drain tube. Install a plug in the housing. Install a plug in the fuel tube connection.

Cummins engine AFC.jpg

Remove the AFC no-air plug, if the fuel pump does not have an AFC. Replace it with the no-air needle valve. The AFC no-air plug is located directly above the throttle shaft.

Tighten the AFC no-air needle valve in the housing to 25 in.lb. [2.8 N*m]. Tighten the jam nut.

Cummins generator.jpg

Remove the AFC cover plate. Remove the AFC  bellows/plunger assembly, if required. Use a pair of snap ring pliers to remove the barrel or barrel plug snap ring.

AFC cover plate.jpg

Thread one of the previously removed 1/4-20 capscrews into the AFC barrel plug. Pull out the barrel plug with a pair of pliers. Discard the three original AFC cover plate capscrews.

If the fuel pump has a functional AFC, use the AFC barrel puller. Service Tool 3375599 to remove the barrel. The AFC cannot to be used with an EFC governor. The AFC cavity is now ready for the installation of the EFC governor actuator.

EFC governor.jpg

Install the O-ring plug on the Governor Plug Tool, Part No. 3376457, approximately three turns. Install the O-ring on be plug.

Caution: Do not tighten the O-ring plug to the plug tool or the tool can not be removed after the plug is inserted in the pump AFC cavity.

Lubricate the O-ring with clean engine oil.

Press firmly until the O-ring plug is seated in the pump housing. Carefully unscrew the plug tool.

unscrew the plug tool.jpg

Install the EFC gasket on the actuator. The gasket will fit only one way. The fuel pump side goes against the fuel  pump.

Caution: Do not use any gasket adhesive or sealant on this gasket.

Check that all of the mounting holes can be aligned. Install the O-rings on the shaft.

Maybe you also like this article: Cummins Engine Electric Fuel Control Governor

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