Fuel Pressure Regulator and Residual Pressure, Checking

Fuel Pressure Regulator And Residual Pressure, Checking

Special tools, testers and auxiliary items required
- Pressure gauge V.A.G 1318
- Pressure gauge adapter V.A.G 1318/7
- Pressure gauge adapter V.A.G 1318/10







- Pressure gauge adapter V.A.G 1318/13







- Spring-type clip pliers VAS 6340

Test sequence
The fuel pressure regulator maintains fuel pressure at a constant 4.0 bar.
- Delivery quantity of fuel pumps OK.

CAUTION: Fuel supply lines are under pressure. Wear protective goggles and protective gloves to avoid damage and contact with skin. Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.







- Place a rag around threaded connection - arrow - and relieve the fuel pressure by briefly opening line.
- Loosen spring-type clamp and remove fuel hose from connection at fuel rail.
- Connect pressure gauge V.A.G 1318 with adapters V.A.G 1318/7, V.A.G 1318/10, V.A.G 1318/13 as shown in illustration.
- The lever or pressure gauge V.A.G 1318 - 1 - points in direction of flow.







- Secure both hose ends - 2 - with clamps.
- Start engine and run at idle speed.
- Measure fuel pressure. Specified value: approx. 4.0 bar positive pressure

If specification is not obtained:
- Check delivery rate of fuel pumps. Fuel Pressure







- If necessary, replace fuel pressure regulator - 2 -.

If specified value is achieved:
- Switch off ignition.
- Check for leaks and residual pressure. Observe pressure drop on pressure gauge. After 10 minutes there must be a residual pressure of at least 3.0 bar.
The holding pressure drops below 3 bar:
- Check pressure gauge for leaks.
- Check right and left fuel pump non-return valves.
- Switch off ignition.
When removing pressure gauge after completing test:







- Place a rag around threaded connection - arrow - and relieve fuel pressure by briefly opening the line.
- Remove pressure gauge V.A.G 1318 with adapters.
- Connect fuel hose to fuel rail again and secure it with spring-type clamp.