16 00 100 Checking fuel tank and tank ventilation system for leaks

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2005 BMW 745i, 2005 BMW 745Li, 2004 BMW 745i, 2004 BMW 745Li, and 2003 BMW 745i. However, it is still accessible from the selected car via links, so may be relevant.

Special tools required:

13 3 010
16 1 070
16 1 171
16 1 174

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

Check tank venting system if a leak is suspected.

Observe safety instructions on raising the vehicle. Refer to 00..... LIFTING VEHICLE WITH A LIFTING PLATFORM .

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

Content of fuel tank:
1. Max. 90% (approx. 79 l)
2. Min. 13% (approx. 11 l, reserve warning lamp 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...20°C).
Never refuel the vehicle directly prior to the leak test due to the strong emission of gas by the fresh fuel.

Remove rear right wheel arch trim. See 51 71... REMOVING AND INSTALLING/REPLACING FRONT BOTTOM RIGHT WHEEL ARCH TRIM

Fold strainer in insect strainer to one side.

Using special tool 16 1 070, seal opening for insect strainer on carbon canister.

Fig 1: Sealing Opening

Courtesy of BMW OF NORTH AMERICA, INC.

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

Fig 2: Clamping Special Tool On Fuel Filler Neck

Courtesy of BMW OF NORTH AMERICA, INC.

Clamp special tool 16 1 174 on fuel filler neck with adjusting wheel (1).

IMPORTANT: Set pressure regulator on special tool 16 1 171 fully in "-" direction.

Connect special tool 16 1 171 using compressed air line (1) to garage compressed air system (8...10 bar).

Fig 3: Connecting Special Tool

Courtesy of BMW OF NORTH AMERICA, INC.

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

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

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 fast-release coupling of special tool 16 1 171.

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

IMPORTANT: Do not under any circumstances increase pressure by more than 0.100 bar as this would result in damage to the fuel tank and venting system.

Using special tool 13 3 010, disconnect supply line from special tool 16 1 171 to tank filler neck.

Allow a rest period of approx. 20 secs.

Read off and note down starting pressure value.

Wait approx. 60 secs.

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

Measurement evaluation:

MEASUREMENT EVALUATION

Pressure drop between 0.008 and 0.010 bar.	Measure again.
Pressure drop in 60 secs. greater than 0.010 bar.	System leaking beyond permitted levels. Carry out leak test. Refer to 16 00 510 Conducting leak test on fuel tank and tank ventilation system .