Thread: Whats supposed to be here?

Originally Posted by Kevin B

Hi all,

This bolt is in the front left hand side of the plenum; is it supposed to be there, if not what is?

1993 Discovery 1 3.5l
2" Lift, Cranked HD Trailing Arms
31" Maxxis Mudders
Tons of Radios, Tons of Spotties

The white nylon joiner in the breather pipe to the left of your picture should be a tee piece with a smaller hose going to the fitting that has a bolt jammed in it. You need the correct tee or make a brass one with a 2mm restrictor jet to the manifold.

Thanks for that, what does it actually do ??

1993 Discovery 1 3.5l
2" Lift, Cranked HD Trailing Arms
31" Maxxis Mudders
Tons of Radios, Tons of Spotties

It sucks.





vapour from the crankcase breather.


Regards Philip A

Is it important? Does it have anything to di with fuel economy? And can it live without it?

1993 Discovery 1 3.5l
2" Lift, Cranked HD Trailing Arms
31" Maxxis Mudders
Tons of Radios, Tons of Spotties

Originally Posted by Kevin B

Is it important? Does it have anything to di with fuel economy? And can it live without it?

The lack of it loads oily fumes into your throttle body at idle instead of the manifold. What you get with this blocked is a dirty and sticking idle speed controller (stepper motor) at the rear of the manifold. Stalling , low or high idle speed results. It may have some effect on economy if your idle speed consistently stays high. Fixing it is recommended if you intend to keep the vehicle long term.

Thanks Bee, that explains why the stepper motor is always dirty, I best fix it then.

1993 Discovery 1 3.5l
2" Lift, Cranked HD Trailing Arms
31" Maxxis Mudders
Tons of Radios, Tons of Spotties

Here is a couple of pics with my setup, mine is black but has the restrictor

While you are in the area you could change the o-rings on the oil cap and the strainer that is on the rocker cover I had to use a chisel to get the old o-rings off.