With Manufacturer's Scan Tool

Fuel Pressure Regulator and Holding Pressure, Checking







The fuel pressure regulator regulates the fuel pressure depending on intake manifold pressure.

Special tools and equipment
- V.A.G 1318 Pressure gauge
- 1318/10 Adapter
- 1318/11 Adapter
- 1318/16 Adapter
- 1318/9 Adapter
- 1318/17 Adapter
- V.A.G 1921 hose clip pliers

Test sequence







- Remove fuse 28 (fuel pump) from fuse holder.


WARNING!
Fuel system is under pressure! Before opening the system place a cloth around the connection. Then release pressure by carefully loosening the connection.







- Pull off supply line/hose -1- and collect leaking fuel with a cloth.







- Connect pressure gauge VA.G 1318 using adapters V.A.G 1318/10,/11 and /16.
- Open shut-off tap on pressure gauge. Handle points in direction of flow.
- Refit fuse 14 (fuel pump) in fuse holder.
- Refit fuse 28 (fuel pump) in fuse holder.
- Start engine and run at idling speed.
- Measure fuel pressure.
Specification: Approx. 2.5 bar







- Pull vacuum hose off fuel pressure regulator -arrow-. Fuel pressure must increase to approx. 3.0 bar.
- Switch ignition off.

If the specification is not obtained:
- Check quantity supplied by fuel pump.

If the specification is obtained:
- Check for leaks and holding pressure by observing pressure drop on gauge.
After 10 minutes there must be a residual pressure of at least 2.0 bar.

If the holding pressure drops below 2 bar:
- Start engine and run at idle speed.







- Switch ignition off after pressure has built up. At same time close pressure measured device VAG 1318 cut-off tap (handle cross through-flow direction -arrow
- Observe pressure drop on gauge.

If the pressure does not drop:
- Check fuel pump non-return valve.

If the pressure drops again:







- Open pressure tester V.A.G 1318 shut-off tap (handle in through-flow direction).
- Start engine and run at idle speed.







- Switch ignition off after pressure has built-up. At same time pinch/seal return hose -2- together.

If the pressure does not drop:
- Replace fuel pressure regulator.
- Erase DTC memory to put learned values in a neutral setting. Reading Diagnostic Trouble Codes

If the pressure drops again:
- Check line connections, O-rings on fuel manifold and injectors for leaks.
- Check pressure gauge for leaks.

If a leak is being repaired on vehicle:
- Erase DTC memory to put learned values in a neutral setting. Reading Diagnostic Trouble Codes


NOTE: Before removing the pressure gauge, remove fuse 28 again and place a cloth around the connections to be loosened.