Trying to sort out a few issues and have found a mess with the vacuum lines. I can not read the diagram on the core support so I ask for advice. By the stepper motor on the rear of the intake; I have 2 vacuum ports (1/8-3/16") and neither of these has anything attached. The fuel pressure regulator has a vacuum line that runs to the water valve vacuum switch on the fire wall on the left side of the engine bay. It took a while to find this valve on the RAVE manual and it does not detail how it is supposed to be plumbed (obviously not correct now). Then this valve has another line that terminates without being attached and I do not know where it goes.

I have run a vacuum line from the lower port on the back of the intake directly to the fuel pressure regulator. I capped the other (upper) port on the back of the intake. I have not attached the water valve switch to anything and one of the lines to it has a one way valve in-line.

The engine is smoother with a steady idle but the idle is too low.

I assume the 94-95 models are plumbed alike so any help would be appreciated.

 

What is a water valve vacuum switch? been doing this for along time and ?????

The fuel pressure reg vac line should lead to the back side of plenum.
Vacuum advance module on distributor should also have a line leading up to the top of plenum.

 

It is shown on page 746 of the RAVE manual and the heading is VACUUM SWITCH - WATER VALVE and looks to be the control for the valve that controls the flow thru the heater core.



I have the FP reg routed to the plenum (incorrectly said intake previously) and the dist. vac advance is connected to the port on the throttle body. This still leaves one port on the rear of the plenum that I assume is for the previously mentioned valve.

 

The other goes to the bluish green switch thong on the firewall, to the left of the stepper motor, then out of it to the water valve. I think it electrically opens vacume when you turn the heat on.

 

Thing not thong, gotta love autocorrect .

 

Don't know what else to tell ya. I have a NAS Disco from '95 and I do not have that vac heater switch on my coolant line to the heater. The only vac lines on my truck coming out of the plenum are:

Right side - Line to brake booster, charcoal canister

Rear - Fuel pressure reg.

Top - Dizzy.

And of course the oil breather lines... check this other post for the diagrams under the hood and some other pics.

https://landroverforums.com/forum/di...-layout-44078/