BMW 7 Series: Checking Fuel Tank And Tank Ventilation System For Leaks

Notes

NOTE: The following procedure is only applicable to vehicles without the tank leak diagnosis module.

Necessary preliminary work

• Remove rear right wheel arch trim.

Comply with the following conditions in order to obtain plausible test results:

• Content of fuel tank:
  1. Maximum 90 %
  2. Minimum 13 % (reserve telltale must not light up)
• Park the car in the workshop at least 2 hours before the test so that the fuel temperature is approximately that of the workshop temperature (ideal fuel temperature approx. 10... 20ºC).
• Never refuel the vehicle directly prior to the leak test due to the strong emission of gas by the fresh fuel

Using special tool 16 1 070 , seal opening (1) on carbon canister.

Fig. 1: Sealing Carbon Canister Opening Using Special Tool (16 1 070)

Remove fuel filler cap and connect special tool 16 1 174 to fuel filler neck.

Using thumbwheel (1), clamp special tool 16 1 174 to fuel filler neck.

Fig. 2: Clamping Special Tool (16 1 174) To Fuel Filler Neck Using Thumbwheel

IMPORTANT: Turn pressure regulator on special tool 16 1 171 counter-clockwise as far as the stop.

Using compressed air line (1), connect special tool 16 1 171 to workshop compressed air system (8... 10 bar).

Connect pressure sensor (2) from Diagnosis and Information System with a measuring range of 0...3.5 bar.

IMPORTANT: Do not connect quick-release coupling (3) of special tool 16 1 171 as yet.

Fig. 3: Identifying Compressed Air Line, Pressure Sensor And Quick Release Coupling

Select "Measurement" function on Diagnosis and Information System (DIS).

Set measuring range according to pressure sensor to 0...3.5 bar.

Using pressure regulator on special tool 16 1 171, increase pressure by 0.050 bar.

Connect special tool 16 1 174 to quick-release coupling of special tool 16 1 171.

Using pressure regulator on special tool 16 1 171, reset pressure in fuel tank to 0.050 bar above atmospheric.

IMPORTANT: Do not under any circumstances increase pressure by more than 0.100 Checking fuel tank and tank ventilation system for leaks Page 3 of 4 bar as this would result in damage to the fuel tank and the fuel tank venting system.

Using special tool 13 3 010 , disconnect delivery line (1) from special tool 16 1 171 to fuel filler neck.

Allow a rest period of approx. 20 sec.

Read off and note down starting pressure value.

Approx. Wait 60 seconds.

Read off final pressure value and compare with starting pressure value.

Measurement evaluation:

Fig. 4: Pinching Off Fee Line Using Special Tool (13 3 010)

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