Met dank aan Wesley86!

The avac is relative simple and easy to use but is often dismissed by those that do not know how it works as being troublesome.

Iím now on over 60k with my s16 in my ownership and its always being fine!!!!

The control unit aka electro solenid is located on the passenger side(bestuurder) of the cylinder head just behind and below the brake vacuum pump the, silver part with the silver pipe coming off it is the vacuum pump.

The solenoid has three connections on it:
1: rear connection closest to bulk head, hose runs up and though bulkhead;

2: top branch runs to top of inlet manifold where it joins a T- piece, one hose runs to one diaphram other to the other;

3: runs across to the front of the inlet manifold, following the line of the metal pipe work and goes down to the lowest join on the middle part of the inlet manifold.

You then also have two hoses which are on the ecu, the first runs from the ecu T-piece to the vent cylinder. This hose joins the rear of the cylinder away from the sticky out part. The other hose closest to the sticky out part runs to the metal pipe that runs across the inlet manifold area.


Does your s16 suffer from flat spots?
Doesnít it perform like you would expect?

If so then look at this guide:

Are the valves opening and closing correctly?
1: check all associated pipe work as detailed above for splits/cracks;

2: to check the operation of each diaprham do the following check, remove the hose from one diapram inlet at a time, put your thumb over the end of it and rev the engine, if you feel a suck on your thumb then the pipe work and valve is ok BUT the diapramh is split and causing the problem;

3: if no suck is felt and non of the hoses are split or cracked then the solenoid on the end of the engine is at fault, this is around £25 for a new one from peugeot;

4: if you feel suction on each hose then the fault lies with the diaphrams and these should be replaced approx £45 each from peugeot.


1: to aid the successful running of the car and to ensure no flat spots then the bars from the diaprham to the cam need to be set correctly to ensure they open and close fully;

2: if they donít open/close fully then you need to disconnect the hose from each in turn, remove the two 10mm bolts that hold them to the bracket and flick the ball joint off the cam so as you can adjust it;

3: grip the metal shaft securely and gently turn the ball joint on the thread, be very careful they are fragile and if you break one you have to buy a complete unit, adjust it up or down until the cam (triangular part ) is resting on the stop on the manifold at rest and opens through 90 deg when working.