Electrical/Vacuum Solenoid. Mityvac Mityvac Vacuum Pump, mv8000, Item 39522, 39522, Silverline Elite MV8500

ELECTRICAL /VACUUM SOLENOID

SERVICE PROCEDURES

1) Disconnect vacuum and electrical connectors from the solenoid. Connect the pump to port “B” and attempt to apply vacuum with pump. Vacuum should be released through port “A” (FIGURE 13).

2) Using jumper wires, connect negative solenoid terminal to ground and apply 12 volts to the positive terminal. Apply vacuum to port “B”.

Vacuum should hold and not bleed off. If the solenoid does not hold vacuum, replace solenoid.

3) With solenoid still energized, move vacuum pump to port “A”. Attempt to apply vacuum.

Vacuum should be released through the air filter and no vacuum should be present at port “B”.

Port “A”

Positive Terminal

Air Filter

Port “B”

FIGURE 13: TYPICAL VACUUM SOLENOID

THERMAL-CONTROLLED VACUUM-SWITCHING VALVES

SERVICE PROCEDURES

These control valves are called Ported Vacuum

Switches (PVS) when used on Ford engines. Thermal

Ignition Control (TIC) valves when used on Chrysler products, and Distributor Thermal Vacuum-Switches

(DTVS) when used on General Motors engines.

The two-port valve is used to stop EGR while the engine is cold. This type of thermal switch is needed to provide good drivability by limiting the entrance of EGR until the engine is warmed up.

The three-port valve is commonly called a cooling system PVS because it switches the vacuum source to the distributor from ported to full intake vacuum.

The four-port valve has been used in some Ford engines to bypass the spark delay valve and cut out the EGR system when the engine is cold.

SERVICE PROCEDURES

Follow this procedure to test the two-port vacuum-switching valve:

1) Apply 10” Hg of vacuum to the bottom port of the valve with your vacuum pump and measure the results with a second vacuum gauge as shown in the accompanying illustration (FIGURE 14).

2) The valves are color-coded and the green valve should open and pass vacuum at 68°F, the black valve at 100°F.

Above

Code Temperature

Green

Black

Plain or Blue

68°F

100°F

133°F

1) Remove both hoses

from valve

3) Apply 10 inches vacuum to the valve

5) See if there is a vacuum reading on this gauge

Color code

RESULTS:

No Vacuum

Vacuum

Replace the PVS valve

PVS valve is open

Vacuum when Replace the coolant is cold PVS valve

2) Connect a vacuum gauge

4) Operate the engine

until the coolant warms

to one port and a remote

vacuum supply to the other

above the valve setting (see table)

FIGURE 14: TESTING THE TWO-PORT PVS

Page Number - 18 Form 824345

THERMAL-CONTROLLED VACUUM-SWITCHING VALVES

3) If full vacuum flows through the valve when heated, it is okay. If there is no vacuum flow or there is vacuum flow when the coolant is cold, replace the valve.

Follow this procedure to test the three-port vacuum-switching valve:

1) Apply 10” Hg of vacuum with your vacuum pump to the middle port of the valve with a vacuum gauge at each of the other two ports.

2) Refer to the same color-coded valves and same temperature specifications as for the two-port valve above. If the vacuum switches at the specified temperature, the valve is okay. If there is no vacuum to the lower port above the specified temperature, replace the valve.

The four-port valve must be tested two times, once at the top two ports and once at the bottom two ports as shown in the accompanying illustration

(FIGURE 15).

1) Apply 10” Hg of vacuum with your vacuum pump to one of the top two ports. The valve should hold vacuum when above the specified operating temperature.

2) If flow occurs when the valve is warm, replace it.

3) For the lower two ports, vacuum must pass through the valve only when the engine is warm; otherwise, replace the valve.

3) Gauge will read zero

4-PORT PVS TEST

UPPER VALVE FLOW

Vacuum Gauge

2) Gauge will read 10”

4) When engine is

warm (coolant

above 125°F)

RESULTS:

No vacuum when warm

Vacuum when warm

LOWER VALVE FLOW

Upper valve okay

Replace PVS

1) Warm engine

(above 125°F)

1) Apply 10” vacuum

(cold engine)

3) Gauge must read source vacuum

When engine is cold, vacuum reading should be zero

RESULTS:

Vacuum when warm

No vacuum when warm

Lower valve okay

Replace PVS

FIGURE 15: TESTING THE FOUR-PORT PVS

Form 824345

2) Apply 10” vacuum

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