Thread: 3.9efi vacuum hoses Rave?

What is the question? Which hoses?

Every loose hose hanging around will have a home.
I know it is in hindsight but it is always a good idea to stcik some masking tape on each hose and label it.
However it pretty well doesn't matter where same size hoses are fitted on the plenum, except for vacuum advance which is above the throttle body.
Regards Philip A

Hi Philip,

I did take photos of everything but a couple of areas were hidden.

Okay the distributor has 2 vacuum hose locations. One of them goes to the top of the plenum. But the other?

Also, at the back of the plenum there are 2 hose locations. I also found a left over vacuum hose that has a really small vacuum unit attached to it the size of a 10c piece. Not sure if this was off the other motor. I've noticed that the later 3.9 plenum has an extra hose outlet at the back of the plenum, although I used my original.

Okay the distributor has 2 vacuum hose locations. One of them goes to the top of the plenum. But the other?

The one nearer to the distributor is not used. That is vacuum retard.

Also, at the back of the plenum there are 2 hose locations

The stub on the IAC housing attaches to a hose that goes to the Fuel pressure regulator which is on the fuel rail immediately below.
I have never seen another stub or is it a hose you are referring to? the vents for gearbox and transfer come out there, and the inlet for the crankcase ventilation on older 3.5 engines. On a 3.9 the inlet for the crankcase ventilation is on the top of the LH rocker cover and should have a small air cleaner on top made of plastic with a small foam filter. Is that the 10C piece thing. Without the filter it is a flat disc with a hole in the middle.
Regards Philip A

Originally Posted by PhilipA

The one nearer to the distributor is not used. That is vacuum retard.


The stub on the IAC housing attaches to a hose that goes to the Fuel pressure regulator which is on the fuel rail immediately below.
I have never seen another stub or is it a hose you are referring to? the vents for gearbox and transfer come out there, and the inlet for the crankcase ventilation on older 3.5 engines. On a 3.9 the inlet for the crankcase ventilation is on the top of the LH rocker cover and should have a small air cleaner on top made of plastic with a small foam filter. Is that the 10C piece thing. Without the filter it is a flat disc with a hole in the middle.
Regards Philip A

Hi Philip,

The other later model plenum I have has another stub at the back. Interseting aswell is that the water outlets on the later manifold are in different locations to that of the earlier ones.

I used the later model rocker covers and it has a nipple on the top of the LH rocker cover. My older one has the flat disc you talk of. When I got the motor it had a long piece of vac hose that attached to the nipple at the LH rocker cover and tape saying to ZF auto. However my auto vac hoses just loop over not to far from the auto dipstick not connected to anything.

No the 10c thing I have is an inline device that has a small diaphram in it, and only lets air through one way. It's connected to vac hose either side and about 30cm long all up.

Cheers