EGR Thermal Vacuum Switch

[johnwom]

Hello again,
In response to some replies received regarding how to get The Chief to run better I am trying to get my EGR system hooked up properly.

Is the EGR valve the little thingy that looks like a flying saucer with a tank turret on top of it located at the back of my intake manifold? If so, mine has no line hooked to it.

My Technical Service Manual shows that the EGR valve should be connected to to the EGR CTO switch via the thermal vacuum switch (TVS) in the air cleaner cylinder.

Problem is, I have two TVS' in my air cleaner; one is for the trap door in the air cleaner snorkel and one for the EGR system. Niether is hooked up so I don't know which is which and the service manual isn't clear on this.

One is very close to the carb, made of metal says "OCL".

The other one is on the outer rim of the cleaner and is small, round, made of plastic and has a Ford part number on it.

Also, the mechanism that opens the trap door to the stove on the exhaust manifold has a vacuum tube hookup also with nothing run to it. Does anyone know where the vacuum for this switch is supplied?

Many thanks,
John

[Ernzo]

The one on the side is the egr one. There ought to be 2 trap door on the Air CLeaner Housing. Both are vacuum operated. IF both are disconnected, then the doors are staying closed all the time. Best to wire them open for the time being. The routing is fairly easy to see on the diagrams available here.
The thermal switch on the bottom of the Air Cleaner Housing is for the trap doors.

[ October 22, 2002, 10:24 PM: Message edited by: Ernzo ]

[Bob Barry]

Well, the outer door is normally open unless closed by vacuum, but the inner-door is normally closed, and only opened by vacuum when the engine is running (it keeps fuel vapors from escaping into the atmosphere. supposedly). The outer door is controlled by that thermostatic switch under the air-cleaner housing, while the inner one should be hooked to straight manifold vacuum (both with reverse check-valves so they don't go flapping open or shut when you whomp on the throttle and the vacuum-signal disappears).

[johnwom]

Thanks for the tips fellas.

OK, so now I know which TVS is which. Now how do I know which side of the switch is 'in' and which side is 'out'? Does that make sense?

They both have two nipples on them. So, for the TVS that goes to the EGR system, one nipple should go out to the EGR valve and the other should go to the CTO, right? How will I know which nipple goes to the CTO & which to EGR valve?

Many Thanks,
John

[ October 23, 2002, 12:23 PM: Message edited by: johnwom ]

[Bob Barry]

It doesn't really matter; it's a simple on-off switch that isn't directional.

There should be a molded rubber vacuum connector, however, to which the actual vacuum hoses connect. You can hook them up directly if that's missing, but it's easier to pop off that molded connector when you want to remove your air-cleaner housing.

[johnwom]

Ah, thanks Bob, that's a great tip. Removing the air cleaner is probably how this got all messed up in the first place.

Thanks,
John
:cool: