2049586.2

Technical product information
Topic
Market area
Brand
Transaction No.
Level
Status
Release date
Misfiring, W12 TSI - Excessive carbon build up cylinder leakage
Bentley: worldwide (2WBE)
Bentley
2049586/2
EH
Released for publishing
07-Jun-2018
New customer code
Object of complaint
Complaint type
information, navigation, communication, entertainment -> symbolic fault indicators -> emission control fault
indicator
engine -> engine operation -> power development -> engine power
functionality ->
activates
functionality -> uneven
Vehicle data
W12 TSI engine vehicles
Sales types
Type
3S3*
4V14A*
4V14A*
MY
2018
2018
2019
Brand Designation Engine code Gearbox code
E
*
*
E
*
*
E
*
*
Documents
Document name
master.xml
Final drive code
*
*
*
Position
Technical product information
Misfiring, W12 TSI - Excessive carbon build up cylinder leakage
Transaction No.: 2049586/2
Release date: 07-Jun-2018
Customer statement / workshop findings
Customer statement: Emission control warning signal displayed, engine misfire
Workshop findings: Event entries in engine control unit relating to cylinder misfires – excessive carbon build up to leading to cylinder leakage and
spark plug foul
Technical background
Deviations in the country-specific fuel specifications can lead to carbon deposits on the injectors. If pronounced these deposits can lead to spark plug
fouling, cylinder leakage and fouled injectors all influencing combustion in the cylinder. As a result the above event entries are logged in the engine
control unit
Production change
None
Measure
1. Follow DISS best practice, ‘POOR ENGINE RUNNING COMPLAINTS (MISFIRES),’ in order to confirm that the root cause of the misfire is excessive
cylinder carbonisation leading to excessive cylinder leakage/fouling.
2. Raise a DISS query, this action is part of DISS best practice but is an essential element of the investigation
3. Ensure cylinder compressions are tested and recorded, this action is part of DISS best practice but is an essential element of the investigation
4. Ensure cylinder leakage is checked and recorded, this action is part of DISS best practice but is an essential element of the investigation
5. From two of the cylinders that have recorded misfires take borescope images of each inlet valve stem
6. Note: The following operations should only be carried out if excessive carbonisation is confirmed
7. Check and if necessary correct allengine and transmission fluid levels
8. Fill fuel tank
9. Add two 90 ml doses of Fuel additive (part number G001770A2) to the fuel load
10. Run the engine at idle for 8 hours – Periodically check to ensure engine coolant temperature is within safe limits – do not allow engine to
overheat
11. Repeat operations 3 through 5 and compare results if improvement is noted repair is complete
12. If no or little improvement is recorded then the condition of the spark plugs and low pressure injectors willneed to be confirmed and replaced
where necessary
13. If this repair procedure is not successful report back via DISS query
14. On successful completion check and if required drain any excess oil from the intercoolers reference TPI 2050222
15. Before returning vehicle to customer top up to fill the fuel tank
Parts information
Part number
Description
Quantity
G001770A2
Additive
2