B64-67: From B22-23: Rest Pressure Drops
From B22 and B23: Rest pressure dropsWhen the fault has been rectified proceed with B23 and B24
B64
Check the rest pressure with gauge cock in position 1
Turn on the ignition to build up the pressure in the system. Turn off the ignition.
Turn the gauge cock on 5011 to position 1 (towards the fuel distributor).
Wait and record the pressure after 5 minutes (this is necessary because the fuel accumulator compensates for any leakage as long as it contains fuel under pressure).
Pressure does not drop in position 1: the fault is due to one or more of the following:
- fuel line leak from the control pressure regulator
- 1975-1977 the control pressure regulator allows too much fuel to flow through. Test with a new regulator
- 1978- the needle valve in the line pressure regulator does not close. Clean/replace the needle valve and fitting.
B65
Check for external leakage
(Between fuel pump and fuel distributor.)
For cars with a fuel leakage return line between the fuel accumulator and fuel tank: remove the tank cap to release any overpressure and disconnect the hose from the fuel accumulator.
Check for leakage and reconnect the hose.
B66
Make sure that the line pressure regulator does not leak
Unscrew the fuel tank cap to release any overpressure in the tank.
Turn on the ignition to build up the pressure.
Turn off the ignition.
Detach the return line (in the engine compartment) and hold the end of the hose up. If fuel flows Out of the hose. the line pressure regulator is leaking.
Reconnect the return line.
Line pressure regulator leaking: renew the 0-ring. If this does not help, renew the complete fuel distributor.
B67
Check the fuel pump non-return valve
Turn on the ignition to build up the pressure.
Turn off the ignition.
Block the line between the tank pump and fuel pump. Use clamping pliers 2901.
Record the rest pressure for 5 minutes.
Rest pressure drops: start injector or line to it, leaking.
Rest pressure does not drop: non-return valve is leaking. renew.