Function

The system pressure regulator has become smaller and smaller with the progressive development of the fuel injection systems. Recently it may also be integrated in the fuel filter. Without connection on top and in different shape it can also be found in the central injection. Its construction is so simple and effective that it seems indispensable everywhere.

How it works

It has three connections. The system pressure originates to the left visually speaking. It should be regulated. If the pressure is too high, it presses the spring-loaded diaphragm upwards and the runback below opens. To ensure the sealing a sphere is located between the locking plate and the diaphragm plate. The multipoint injection features an upper connection which is connected with the inlet manifold. This way the pressure difference is always constant between inlet manifold and distributor pipe. The injection amount should absolutely only dependent on the injection pulse timing.
Older multi-position fuel injection systems (not KE-Jetronic!) have between 2,5 and 3,5 bar absolutely measured system pressure, newer ones can reach just about 4 bar.