Checking Fuel Pressure

WARNING: This page is about a different variant/trim than selected.

WARNING: Risk of damage to skin and eyes from toxic and caustic effects of fuel.
→ Wear personal protective gear when working with fuel.
→ In case of contact with skin or eyes wash immediately with plenty of warm water and acid-free soap.
→ Consult a doctor as soon as possible.

WARNING: Highly inflammable or explosive materials

Danger of fire or explosion
→ Avoid contact with hot parts or sources of ignition.

→ Use suction to remove ignitable vapors.

→ Attach warning sign in a clearly visible position.

→ Contain leaked media using non-flammable absorbent material and put it in a container designed for this purpose for disposal in accordance with local requirements.

→ Secure collection containers/vessels to prevent them from tipping over.

Information

The battery voltage must not fall below 12.5 volts during the delivery rate/pressure check.

Information

There is no need to create a Vehicle Analysis Log (VAL).

Information

The fuel pressure in the low-pressure system can also be read out using the PIWIS Tester.

> P378a - Pressure gauge > Fuel pressure test tool with connecting line must be connected to the fuel line.

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Fuel pressure test tool
Check fuel pressure.
Connect the PIWIS Tester to the vehicle and switch on the PIWIS Tester .

Switch on the ignition.

Start diagnostics.

Select "DME" control unit.

Select the "Drive links/checks" tab.

Select "Drain tank" .

Select the "Drain fuel tank" sub-procedure and press F12 to continue.

Follow the instructions on the Tester.
Read off the pressure value on the pressure gauge
IMPORTANT: (The relative pressure is displayed = setpoint value).

Check fuel pressure:

Set-point value C2

> Absolute fuel pressure 6 bar +/- 0.2 bar

Set-point value for all-wheel drive vehicles

> Absolute fuel pressure 6.2 bar +/- 0.2 bar
Check holding pressure.
Read off the pressure on the pressure gauge after 20 minutes.

> Pressure 4.0 bar +/- 0.2 bar

> Pressure 4.0 bar +/- 0.2 bar
To be on the safe side and as a check, the fuel pressure can also be read out as absolute pressure (relative pressure + 1 bar) on the PIWIS Tester using the following path:
Select "DME" control unit.

Select the "Actual values/input signals" tab.

Select the menu item "B_Fuel system" and press F12 to continue.

Select the sub-procedure "B220_Fuel low pressure actual value" and press F12 to continue.

Follow the instructions on the Tester.

Check fuel pressure:

Location	Description	Type	Basic value	Tolerance
PIWIS Tester fuel pressure display	Set-point value C2	Absolute fuel pressure	6 bar	+/- 0.2 bar
PIWIS Tester fuel pressure display	Set-point value for all-wheel drive vehicles	Absolute fuel pressure	6.2 bar	+/- 0.2 bar

Switch off ignition, switch off the PIWIS Tester and disconnect adapter line in the vehicle.