Correct Vapor Canister Purge Valve Operation

[Kevin718]

Does anyone know the correct operation of the purge valve located on top of the vapor (charcoal) canister?

My thoughts are:
1. The purge signal to operate the purge valve should hold a vacuum if the diaphragm in the valve is good.
2. The line going to the PCV valve should hold vacuum (not leak) when there is no vacuum applied to the purge valve.
3. The line going to the PCV valve should not hold vacuum (leak by pulling air through the canister) when there is vacuum applied to the purge valve.

Is this correct? I just received a new vapor canister and the purge valve connection holds a vacuum, but the PCV line never seems to close. It leaks if there is vacuum applied to the purge valve or not.

[Kevin718]

btt

[Michael F]

It is working OK, the primary purge vacuum line (the one going to the PCV line)is open and when the purge valve is opened at 12" ported vacuum the secondary purge circuit is opened, and the canister is purged at a much higher rate.

Per the TSM

[ACDuff]

I've installed my spare Motorcraft 2150 as it runs ok but a little rough at idle. Looking at getting all the vacuum lines in good shape to see if that will help. Used carb cleaner and don't seem to have any leaks. Don't have a stock system as the air pump is removed. There are four lines comming off the vacuum distributor on the back on the intake. One connects into a plug with the EGR and air cleaner. One connects to the back on the intake. One connects to the front of the carb. The other is just plugged with a bolt. Any clue where it should go?

Alan
'85 GW

[Am4wag]

Sounds like a dual CTO these hoses are connecting to.The hose you mention being plugged with a bolt goes to the air by-pass valve,which you won't need if your air pump is removed.

[ACDuff]

Thanks Am4wag, another question. The PCV valve only has one port which connects to a line on the air cleaner. From looking at the the vacuum schematic it looks like it should connect to a port on the back of the carb. However, the lower port of the back corner of the carb connects to the vacuum nipple on the choke pull. The other in the middle of the carb is connected to a metal line comming off a plate on the manifold. The plate has another tube connecting to the choke. Both are broken loose on the plate.

Alan
'85 GW

[Kevin718]

Michael,

Thanks for your input. That makes me feel better about my new vapor canister.

Alan,

Concerning the vacuum line connections to the carb:
Note: This is information from a 91 GW with a 2150 carb.
The connections are:
1. PCV Valve - Lower rear DS (Driver's Side)
2. Choke Vac. Actuator - Lower rear PS (Passenger's Side)
3. Distributor Vac. Advance - PS toward front
4. Power Valve - Front center
5. To Dual CTO for Vapor Canister Purge, and To EGR CTO - Front DS
6. From Carb to Manifold Crossover Heater - Upper rear PS to manifold plate
7. From Manifold Crossover Heater to Choke Coil - Tube from manifold plate into bottom of choke coil

The PCV valve should have 3 connections.
1. To manifold.
2. To carb (this is inline with the manifold connection).
3. To vapor canister (this is the tee connection).