Emission Systems - Service Guidelines
REF. NO. MBNA 00/30TO: OUR MERCEDES-BENZ PASSENGER CAR DEALERS
DATE: September 1987 (supersedes MBNA 14/3 & MBNA 00/23)
SUBJECT:
GUIDELINES FOR TURBODIESELS WITH TRAP OXIDIZERS
M.Y. 1985/1986 CALIFORNIA VERSION VEHICLE
ALL M.Y. 1987 VEHICLE
Since all dealers will now be involved in diagnosing and servicing the emission control system of turbodiesel engines with trap oxidizers, we have compiled a list of guidelines to be followed and would like to re-emphasize the interdependence of all the components in the emission control system in order that:
- exhaust emission legal requirements are met
- a trouble-free service life of the total system is achieved
- good vehicle and engine performance (e.g. cold start, smooth idle, good acceleration, low fuel consumption and smooth gear shift quality) are obtained
Note:
Any modification to the emission control system is illegal and can lead to the malfunction of emission control and other vital engine components as well as possible legal penalties for tampering.
To assure that the complete system will function correctly the following conditions must be strictly adhered to:
- all maintenance/service schedules must be performed at the prescribed intervals, including checking and setting the injection pump timing at 30,000 miles
- the EGR and AR (Air Recirculation) system must operate properly to maintain high enough exhaust temperatures for normal trap oxidizer function
- the air intake system must be unrestricted which includes the air filter, air ducts and turbocharger.
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In case of performance complaints caused by high back pressure, test all system components before replacing the trap oxidizer and/or other major components. The EDS Quick Test and the test related to the EGR and Trap System should be performed first. A revised EDS Quick Test for engine 603 is in this S.I. The Quick Test for engine 617.95 remains the same. The source literature for the component test procedures is listed.
If regeneration is performed correctly, it will bring the exhaust system back pressure within the prescribed limits for the different engines (less than 2.0 bar for engine 603 & less than 1.3 bar for engine 617).
IMPORTANT!
Replacement of the trap oxidizer, except at the 30,000 mile interval for engine 617A, (see S.I. MBNA 09/6, September 1987) may only be carried out with prior zone approval. Any non-approved replacement or return of a trap oxidizer that can be regenerated will be rejected.
Please provide the Zone Service Representative with a record of specific customer driving habits (e.g. mostly short distance driving, extended idling or rush hour stop and go traffic, special climatic conditions etc.) that could help us analyze the situation for each trap oxidizer replaced.
DIESEL FUEL AND USE OF ADDITIVES
The quality of diesel fuel at the filling station is usually sufficient so that the use of diesel fuel additives is not necessary. However, diesel fuel additives (in this bulletin) may be used, if poor quality diesel fuel problems (such as knocking, rough running, fuel filter clogging etc.) are observed.
Caution!
Many of the over 2,000 different diesel fuel additives on the market contain ingredients such as metal oxides, which will not regenerate, but will clog and damage the trap oxidizer. Use of these types of additives will result in a severe power loss and costly repairs, which will not be covered by warranty.
The use of non-approved additives for trap oxidizer equipped engines is therefore prohibited. Approved additives, if used in case of diesel fuel quality problems, should only be used in accordance with manufacturers instructions.
The products listed have been tested by DBAG and approved for use in all Mercedes-Benz diesel engines when used as directed by the manufacturer.
Please make your customers aware of their obligations as outlined in the Owner's manual.