Engine - Driveway Die Out/Rough Idle/Low Power
NO: 18-05-97GROUP: Vehicle Performance
DATE: Feb. 14, 1997
SUBJECT:
Intake Valve Deposits
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 18-16-93, DATED NOV. 12, 1993 AND 18-20-94, DATED OCT. 21, 1994, WHICH SHOULD BE REMOVED FROM YOUR FILES AND NOTED IN THE 1993 AND 1994 TECHNICAL SERVICE BULLETIN MANUALS (PUBLICATION NO's. 81-699-94000 AND 81-699-95054). ALL REVISIONS ARE HIGHLIGHTED WITH **ASTERISKS** AND INCLUDE MODEL AND APPLICATION CHANGES.
MODELS:
**1989 - 1995** (AA) Spirit/Acclaim/LeBaron Sedan
**1988 - 1993** (AC) Dynasty/New Yorker Salon
**1990 - 1994** (AG) Daytona
**1990 - 1995** (AJ) LeBaron Coupe/LeBaron Convertible
**1992 - 1994** (AP) Shadow/Shadow Convertible/Sundance
**1987 - 1995** (AS) Town & Country/Caravan/Voyager
**1996 - 1997** (NS) Town & Country/Caravan/Voyager
**NOTE:
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A 3.0L ENGINE.**
SYMPTOM/CONDITION:
Driveway die out, rough idle, lack of power, sags, and hesitation.
DISCUSSION:
The above conditions may be the result of a build up of deposits on the back of the intake valves causing blockage of fuel delivery into the upper combustion chamber. This blockage results in fuel starvation. The deposits can be the result of fuel blending methods that have insufficient or ineffective fuel detergent additives.
Fuel quality is a direct result of the crude oil used, the refinement process, the storage, delivery and distribution methods, and the blending of additive compounds. Using fuel with a higher posted octane number does not guarantee high quality, or that it is blended with adequate or effective detergent, corrosion inhibitors, or additives.
Gasoline/Oxygenate blends which use unleaded gasoline and compounds that contain oxygen, such as alcohol, ethanol, MTBE, and ETBE may not indicate that adequate or effective detergent additives are available either.
Gasoline Companies acknowledge that fuel quality is important. A number of them advertise, as well as warrant their fuel is blended to contain the necessary additives for efficient and clean operation of modern vehicles. Fuels available from these companies should be considered to assure full performance and clean operation.
DIAGNOSIS:
Using the Mopar Diagnostic System (MDS) or the Diagnostic Scan Tool (DRB III) with the appropriate Diagnostic Procedures Manual, verify all engine systems are functioning as designed. If Diagnostic Trouble Codes (DTC's) are present, record them on the repair order and repair as necessary before proceeding further with this bulletin. If no DTC's are present, make sure the PCM is at the latest software version.
If all systems are functioning as designed, ask the customer about the fuel that is being used in the vehicle. If there is a question about the quality of the fuel, suggest that only fuels be used that are warranted by the gasoline company against the build up of deposits.
REPAIR PROCEDURE:
Depending on the amount of deposit on the valves, there are several methods that can be used to remove them.
1. The use of Mopar Fuel Injector Cleaner has shown reasonable results on light deposits. Add one bottle of Mopar Fuel Injector Cleaner, p/n 4318007, to a full tank of gas.
CAUTION:
UNDER NO CIRCUMSTANCES SHOULD THIS FUEL INJECTOR CLEANER BE ADDED TO A PARTIALLY FILLED FUEL TANK.
Mopar Fuel Injector Cleaner will remove light deposits that have built up over a period of time. However, it is not intended for continuous use. Owners should be advised of the cause of their driveability concern and a recommendation should be made to try other brands of fuel.
2. For moderate to heavy deposits, the intake valves should be cleaned. The suggested method for cleaning involves removal of the cylinder head from the engine. The head must be disassembled, and the carbon removed from the valves and surrounding components with a wire brush.
POLICY: Information Only