Fuel Pressure: Testing and Inspection

WARNING: Fire Hazard! Do not smoke or have anything in area that can ignite fuel.


Requirements
- fuse No.18 OK
- fuel pumps OK, checking - Repair Group 20
- whenever a fuel line is disconnected always replace the sealing rings







VAG 1318 pressure tester, connecting

- connect VAG 1318 pressure tester to measuring point 1 of fuel distributor using adaptor VAG 1318/4
- disconnect fuel line from cold start valve (N 17) and connect to VAG 1318 pressure tester
- shut-off valve on pressure tester;
Position A - open
Position B - closed







Remote control VAG 1348/3A, connecting
- remove fuel pump relay (J 17) from fuse/relay panel, location 12
- attach VAG 1348/3-2 adaptor wire connector to terminal 4 of fuel pump relay socket in location 12
- connect alligator clip for remote control VAG 1348/3A to battery positive (+)

System pressure, checking

- open VAG 1318 shut-off valve (position A) and operate remote control VAG 1348/3A
- system pressure must be 6.1 to 6.6 bar

If system pressure is not obtained or is too low

- replace fuel pressure regulator

If system pressure too high

- disconnect fuel return line from fuel pressure regulator and provide container to catch overflow

- repeat test

If system pressure OK

- check return line for proper flow, repair or replace as necessary

If system pressure too high

- replace fuel pressure regulator

Differential pressure, checking

- close VAG 1318 shut-off valve (position B)
- disconnect harness connector from differential pressure regulator (N 73)
- operate remote control VAG 1348/3A
- differential pressure must be 0.3 to 0.5 bar below system pressure

If differential pressure NOT OK

- disconnect thin line from fuel pressure regulator and hold in measuring container
- cover or plug open connection on fuel pressure regulator
- operate remote control VAG 1348/3A for 1 minute and measure accumulation
- must be 130 to 150 cc's

If NO

- replace pressure regulator
- reconnect, thin line on fuel pressure regulator

If differential pressure OK

- switch Fluke 83 multimeter to 2 Amp range
- disconnect harness connector from differential pressure regulator







- connect test adaptor VAG 1315A/1 between harness connector and differential pressure regulator
- connect multimeter to test adaptor VAG 1315A/1 using adaptor leads from VW 1594 adaptor-kit
- switch ON ignition
- control current must be 90 to 110 mA

- operate remote control VAG 1348/3A
- differential pressure must be 1.3 to 1.6 bar below system pressure

If differential pressure NOT OK
- replace differential pressure' regulator

If differential pressure and control current not OK

- perform Electrical Test A in Repair Group D2, and/or replace CIS-E Motronic control unit (J 204)

Residual pressure, checking


NOTE: This check is required only if there are hot start problems.

- operate remote control VAG 1348/3A for approx. 5 seconds
- observe pressure drop on VAG 1318 gauge
- after 10 minutes, there must be a minimum pressure of 3.3 bar
- after 20 minutes, there must be a minimum pressure of 3.2 bar

If the pressure drop exceeds these specifications
- check fuel pump check valve
- check sensor plate free play and adjust if necessary
- check fuel distributor sealing rings, replace it necessary

If these checks are OK

- replace fuel pressure regulator