Powertrain Management: Service Precautions

13 02 96 (084) Leaded Fuel With Catalytic-converter Vehicles

All models since Model Year 86

Situation:
The open global market allows us to export catalytic-converter vehicles to those markets to which the BMW Organization has exclusively exported vehicles without a catalytic converter or the"cat-prepared"vehicle version due to the exhaust-emissions legislation in force there or the limited availability of unleaded petrol.
When BMW catalytic-converter vehicles are run on leaded fuel, the following actions described below are necessary depending on the engine type.

Affected vehicles:
All vehicles since Model Year 86 with catalytic converter (without special equipment"cat-prepared" ) - except compressed-natural-gas-driven (CNG) vehicles

Action:
Conversion of the vehicle from"catalytic-conversion version"to"cat-prepared"or"Gulf/Tropics"version.

IMPORTANT:There are two restrictions that must be observed:

1. Compressed-natural-gas-driven vehicles (CNG) are not convertible
Gas-driven vehicles cannot be converted, because there is no"cat-prepared"variant. If such vehicles are run with leaded fuel without being converted, the DME adapts substitute values which trigger a fault message for the CNG component, which in turn leads to the CNG system being deactivated. The vehicle can then no longer be driven on gas.

2. US models can be converted, but only with limitations
a. US models with the M50 or M52 engine and automatic transmission cannot be converted.
b. In the case of the remaining US models (see the list below), it is also necessary to mount tyres from the same speed category as are fitted to the corresponding ECE model.

Reason:
When recoding US models for running on leaded fuel, the "cat-prepared" variant for the ECE or Gulf must be used, because there is no "cat-prepared" variant for the US. This action clears any speed-governing function that may be coded in the DME , which means that the vehicle runs faster after conversion without being type-approved or technically set up for this function.
Since Model Year 90, the top speed of all versions of the following US models is limited:

Limitation 187 km/h (116 mph):
as of 01/94: E36 318i, E36 318is, E36 318ti, E36 Z3 1.9

Limitation 196 km/h (122 mph):
E30 325i, E30 325ix

Limitation 206 km/h (128 mph):
E34 525i, E34 530i, E34 540i, E36 320i, E36 325i, E36 325is, E36 328i, E36 328is, E38 740i, E38 750i, E39 528i, E39 540i; up to 12/93: E36 318i, E36 318is

Limitation 220 km/h (137 mph):
E36 M3

These US models are also set up for their respective limited top speed:
- all-season tyres, H-rated tyres, T-rated tyres depending on the model
- transmission ratio (4-speed automatic), the propshaft reaching its maximum speed at 206 km/h (128 mph).

Procedure:
Proceed as described below, taking into account the two restrictions mentioned above.

A. General actions:
1. In all cases, the catalytic-converter system must be exchanged for an appropriate front silencer (muffler) without catalytic converter. This prevents annoying odors from the build-up of hydrogen sulphide due to the higher sulphur content of leaded fuel ( smell of rotten eggs ).

Comment:
The method practised up to now (for reasons of cost), in which the catalytic converter and oxygen sensor are left fitted in the vehicle, must no longer be used. This is due to vehicle performance problems that arise either straight after conversion or at a later date due to adaptive engine control.

2. Remove the unleaded-fuel reduction sleeve from the tank filler neck or if the reduction is fitted permanently, order the
reduction funnel: Part no. 16 12 1 150 748
with holder: Part no. 16 12 1 150 747

from the Parts department for future use with the vehicle.

As of the E36, it is also possible to replace the entire tank filler neck for the cat-prepared version.

3. Disconnect the electrical plug-in connection for the oxygen sensor and tie back and insulate the sensor connector in the engine wiring harness so that it is protected against water.
4. Remove the oxygen-sensor heater relay - if fitted as standard.
5. Set the idle CO as instructed in the Repair Instructions.
6. For environmental reasons, the tank ventilation function fitted in all BMW vehicles since 09/88, that uses the activated charcoal filter, should be left fitted in all vehicles - i.e. in non-catalytic-converter vehicles , too.

B. Engine-specific actions:
The relevant encoding/programming actions must be carried out using the latest Programming programme (on CD-ROM for downloading via the DIS or from diskette via the MoDiC station to the MoDiC). The path to be selected is specified in the respective engine-specific action.

1. M20 B20/B25/B27 Leaded fuel, RON min. 91 / MON min. 82.5
(since 09/85)
M30 B30/B35
M70

- Recode DME control unit M 1.x to "cat-prepared" or "Gulf/Tropics" (path:"DME variant code"; menu item: "Recoding"), so that tank ventilation via the activated charcoal filter continues to be guaranteed.

2. M40 B16/B18 Leaded fuel, RON min. 91 / MON min. 82.5
M42 B18 Leaded fuel, RON min. 95 / MON min. 85

- Recode DME control unit M 1.x to "cat-prepared" or "Gulf/Tropics" (path: "DME variant code" ; menu item: "Recoding"), so that tank ventilation via the activated charcoal filter continues to be guaranteed.
- Disconnect the electrical plug-in connection from the tank-ventilation valve and insulate connector on the engine wiring harness side to protect it against water (the valve is isolated, i.e. open).
- M40/M42 in E30: Plug together the single-pin plug-in connection on the engine wiring harness in the cable channel on the engine compartment bulkhead (firewall) to make a connection with the CO potentiometer in the air-flow sensor (LMM).
- M40 in E36 up to production date 06/91: Plug together the single-pin plug-in connection at the output of the DME connector in the electronics box (LMM as standard with CO potentiometer in catalytic-converter and cat-prepared versions).
- M40/M42 in E36, production date 07/91 up to 09/92: Plug together the single-pin plug-in connection at the output of the DME connector in the electronics box. Replace the LMM with an LMM with CO potentiometer. See SI 13 02 94 (796)
- M40/M42 in E34 (M40 only) and E36 as of production date 10/92: Replace the LMM with an LMM with CO potentiometer.

3. M43 B16/B18 Leaded fuel, RON min. 91 /
up to 03/96 MON min. 82.5 (knock control)

- Recode DME control unit M 1.x to "cat-prepared" or "Gulf/Tropics" (path:"DME variant code"; menu item: "Recoding"), so that tank ventilation via the activated charcoal filter continues to be guaranteed.
- Replace the LMM with an LMM with CO potentiometer.

See SI 13 02 94 (796).

4. M50 up to 08/92 Leaded fuel, RON min. 95 /
(without VANOS) MON min. 85

- Replace the control unit with an exchange basic control unit
- Programming using the MoDiC for "cat-prepared" or "Gulf/Tropics" version; path: "DME programming"

IMPORTANT: Programming must be performed in "Manual input" mode, i.e. if the prompt"Is faulty control unit still installed in vehicle? Y/N appears while you are in the"Determine basic control unit"path, reply"No". You can then enter the appropriate"Part number - basic control unit", the vehicle ID number and the"Part number - Programmed control unit for cat-prepared"or"Gulf/Tropics".

Please find the"Part number - basic control unit"and"Part number - Programmed control unit"in the Electronic Parts Catalogue.
- Alternative to leaded fuel, RON 91 /MON 82.5: Use the MoDiC to programme the exchange basic control unit for the low-compression engine and"cat-prepared"or"Gulf/Tropics versions".

5. M50 since 09/92 Leaded fuel,
(with VANOS) RON min. 91 /
M60 MON min. 82.5 (knock control)
M73

- Replace the control unit with an exchange basic control unit
- Programming using the MoDiC for"cat-prepared"or"Gulf/Tropics"version; path:"DME programming"

IMPORTANT: Programming must be performed in"Manual input"mode, i.e. if the prompt"Is faulty control unit still installed in vehicle? Y/N"appears while you are in the"Determine basic control unit"path, reply"No". You can then enter the appropriate"Part number - basic control unit , the vehicle ID number and the"Part number - Programmed control unit for cat-prepared"or"Gulf/Tropics.
Please find the"Part number - basic control unit"and"Part number - Programmed control unit"in the Electronic Parts Catalogue.

6. M43 with ASC Leaded fuel,
since 03/96
M44 RON min. 91 /
M52 MON min. 82.5 (knock control)
M62
S50 B32/US
S50 B32

- No new control unit required thanks to"flash technology"
- Programming using the MoDiC for"cat-prepared"or"Gulf/Tropics"version; path:"DME programming"

IMPORTANT: Programming must be performed in"Manual input"mode, i.e. if the prompt"Is faulty control unit still installed in vehicle? Y/N"appears while you are in the"Determine basic control unit"path, reply"No". You can then enter the appropriate"Part number - basic control unit", the vehicle ID number and the"Part number - Programmed control unit for cat-prepared"or"Gulf/Tropics".
Please find the"Part number - basic control unit"and"Part number - Programmed control unit"in the Electronic Parts Catalogue.

7. S38 B36 S70 B56 S70/2 Leaded fuel, RON min. 95 / MON min. 85 (knock control)

- Recode DME control unit M 1.x to"cat-prepared"or"Gulf/Tropics"(path:"DME variant code"; menu item:"Recoding" ), so that tank ventilation via the activated charcoal filter continues to be guaranteed.

8. S38 B38 Leaded fuel, RON min. 95 /
S50 B30 MON min. 85 (knock control)
Leaded fuel, RON min. 91 /
MON min. 82.5 (knock control)

- Replace the control unit with an exchange basic control unit
- Programming using the MoDiC for"cat-prepared"or"Gulf/Tropics"version; path:"DME programming"

IMPORTANT: Programming must be performed in"Manual input"mode, i.e. if the prompt"Is faulty control unit still installed in vehicle? Y/N"appears while you are in the"Determine basic control unit"path, reply"No". You can then enter the appropriate"Part number - basic control unit , the vehicle ID number and the"Part number - Programmed control unit for cat-prepared"or"Gulf/Tropics".

Please find the"Part number - basic control unit"and"Part number - Programmed control unit"in the Electronic Parts Catalogue.

In accordance with the warranty conditions currently valid, reimbursement for this subsequent conversion cannot be claimed from BMW AG under warranty/goodwill.