Differential Pressure Test
DIFFERENTIAL PRESSURE I, CHECKINGWORK SEQUENCE
- close valve on VW 1318 pressure gauge
- turn ON us 4480/3
- differential pressure regulator electrical plug still disconnected
- differential pressure must be 0.2 to 0.5 bar (2.9 to 7.0 psi) less than system pressure
If pressure NOT OK
- disconnect fuel distributor lower chamber return line from diaphragm pressure regulator and hold over measuring container
- plug the open connection to diaphragm pressure regulator
- turn ON us 4480/3 for one minute
- fuel flow quantity must be 130 to 150 cm3/minute
If fuel quantity OK
- replace differential pressure regulator
If fuel quantity NOT OK
- replace fuel distributor
DIFFERENTIAL PRESSURE II, CHECKING
- close valve on VW 1318 pressure gauge
- connect harness adapter VW 131 5A/1 between differential pressure regulator and open harness connector
- connect multimeter us 1119 to harness adapter VW 1315A/1. Set scale to DCA 200 mA
- remove connector from engine coolant temperature sensor (arrow)
- connect 15 kohms side of tool VW 1490 to open temperature sensor harness connector
- turn ignition ON
- turn ON US 4480/3
- differential pressure must be 0.7 to 1.2 bar (10 to 17.5 psi) less than system pressure
- differential pressure regulator current must be 50 to 80 mA
If pressure NOT OK and current reading OK
- replace differential pressure regulator
If pressure and current reading NOT OK
- remove harness adapter VW 1315A/1 from differential pressure regulator
- check electrical resistance of differential pressure regulator
- must be 17.5 to 21.5 ohms
If NOT OK
- replace differential pressure regulator
If OK
- check ground wire of temperature sensor to cold start valve
If ground OK
- check power supply fuse
If fuse OK
- check electrical connections on multi-point CIS-E control unit plug
If connections OK
- replace control unit