Porsche 924 Workshop Manual page 153

924
3. Turn off ignition (detach wire on battery supply
from 1979 models) after reaching "warm" control
pressure and observe pressure drop on pressure
gauge. Pressure will drop quickly at first and then
become stabilized. If pressure continues to drop
quickly (see testing and adjusting specifications),
repeat test with disconnected control pressure cir-
cuit to limit possible causes. Turn valve to posi-
tion 3 for this.
If results are the same, leak is in system pressure
circuit.
If results of second test are okay, leak is in control
pressure circuit.
Printed
in
Germany -
X, 1982
Fuel Mixture
Possible Causes in System
Pressure Circuit:
Check valve of fuel pump leaks.
0-ring in system pressure regulator leaks.
Fuel injectors leak.
Start valve leaks.
25
Fuel injectors and start valve must be inspected
separately. Replace check valve of fuel pump and
0-ring of system pressure regulator in fuel distriputor
separately and repeat test.
Possible Causes in Control
P ressure Circuit.
Control pressure regulator leaks.
Control pressure reducing valve leaks.
Checking Entire Fuel System for Leaks 25 - 8 c