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Clogged Fuel Injectors
Multiple Driveability Symptoms Due to Clogged Fuel Injectors (Clean Injectors)
2000-2003 Pontiac Bonneville, Grand Am, Grand Prix, Sunfire
2000-2003 Buick Century, LeSabre, Park Avenue, Regal
2002-2003 Buick Rendezvous
2002-2003 Cadillac Escalade, Escalade EXT
2003 Cadillac Escalade ESV
2002-2003 Oldsmobile Bravada
2000-2001 Pontiac Transport
2000-2002 Pontiac Firebird
2001-2003 Pontiac Aztek
2002-2003 Pontiac Montana
Some owners may comment on driveability symptoms of long or hard starts, chuggle, rough idle and light or intermittent misfire. The malfunction indicator lamp (MIL) may also illuminate.
Due to various factors, the fuel injectors may become restricted. Extensive testing has demonstrated that fuel related issues are the cause of clogged injectors. At this point, no specific fuel, fuel constituent, or engine condition has been identified as causing the restriction. The restriction causes the engine to operate at a lean air fuel ratio. This may either trigger the MIL to illuminate or the engine to develop various driveability symptoms.
Fuel injector restrictions, deposits, can be cleaned on the vehicle using the following procedure. Under NO circumstances should this procedure be modified, changed or shortened.
The recommended mixture amount of GM Top-Engine Cleaner has been increased from 5% used in prior procedures to 10%. This increase was implemented to improve the effectiveness of the injector cleaning procedure. Follow the cleaning procedure carefully to minimize the risk of fuel system damage. Testing has demonstrated that exceeding the 10% cleaning solution concentration does not improve the effectiveness of this procedure. GM Top-Engine Cleaner is the only injector cleaning agent approved for use with General Motors fuel system components. Other injector cleaners, while effective, may cause damage to plastics, plated metals or bearings. General Motors has completed extensive laboratory testing of GM Top-Engine Cleaner, and can assure its compatibility with General Motors fuel system components, as long as the cleaning procedure is followed correctly.
This bulletin recommends the use of pre-measured containers of GM Top-Engine Cleaner, P/N 12346535, - U.*. USAGE ONLY. Pre-measured containers eliminate the need to measure the amount of GM Top-Engine Cleaner being added to the J 35800-A, injector cleaning tool. In Canada, use P/N 992872. It will be necessary to measure and dispense Top Engine Cleaner into the J 35800-A, injector cleaning tool.
Injector Cleaning Procedure
GM Top-Engine Cleaner is the only injector cleaning agent recommended. DO NOT USE OTHER CLEANING AGENTS, AS THEY MAY CONTAIN METHANOL WHICH CAN DAMAGE FUEL SYSTEM COMPONENTS. Under NO circumstances should the GM Top-Engine Cleaner be added to the vehicle fuel tank, as it may damage the fuel pump and other system components.
Do not exceed a 10% cleaning solution concentration. Higher concentrations may damage fuel system components. Testing has demonstrated that exceeding the 10% cleaning solution concentration does not improve the effectiveness of this procedure.
During this procedure, you will need a total of 960 ml (32.4 oz) of cleaning solution (10% Top Engine Cleaner/90% Regular Unleaded Gasoline). That is two tanks of solution for the J 35800-A Fuel Injector Cleaner Tank. Other brands of tools may have a different capacity and would, therefore, require more or less tanks to complete the procedure. You must use all 960 ml (32.4 oz) of solution (10% Top Engine Cleaner/90% Regular Unleaded Gasoline) to insure complete injector cleaning.
1. For U.*. dealers, empty 2 pre-measured GM Top-Engine Cleaner containers, 24 ml (0.812 oz) each, P/N 12346535, into the J 35800-A, injector cleaning tank. For Canadian Dealers, measure and dispense 48 ml (1.62 oz) of Top-Engine Cleaner, P/N 992872, into the J 35800-A, injector cleaning tank. If you are using any other brand of tank, you will need a total of 96 ml (3.24 oz) of Top-Engine Cleaner mixed with 864 ml (29.16 oz) of regular unleaded gasoline.
2. Fill the injector cleaning tank with regular unleaded gasoline. Be sure to follow all additional instructions provided with the tool.
3. Electrically disable the vehicle fuel pump by removing the fuel pump relay and disconnecting the oil pressure switch connector, if equipped.
4. Relieve fuel pressure and disconnect the fuel feed and return lines at the fuel rail. Plug the fuel feed and return lines coming off the fuel rail with J 37287, J 42874 or J 42964 as appropriate for the fuel system.
5. Connect the J 35800-A to the vehicle fuel rail.
6. Pressurize the J 35800-A to 510 kPa (75 psi).
7. Start and idle the engine until it stalls, due to lack of fuel. This should take approximately 15-20 minutes.
8. Refill the J 35800-A injector cleaning tank per steps 2 and 3.
9. Start and idle the engine until it stalls, due to lack of fuel. This should take approximately 15-20 minutes.
10. Disconnect J 35800-A from the fuel rail.
11. Reconnect the vehicle fuel pump relay and oil pressure switch connector, if equipped.
12. Remove the J 37287, J 42874 or J 42964 and reconnect the vehicle fuel feed and return lines.
13. Start and idle the vehicle for an additional 2 minutes to ensure residual injector cleaner is flushed from the fuel rail and fuel lines.
14. Repeat Steps 1-5 of the Injector Balance Test and record the fuel pressure drop from each injector.
15. Subtract the lowest fuel pressure drop from the highest fuel pressure drop. If the value is 15 kPa (2 psi) or less, no additional action is required. If the value is greater than 15 kPa (2 psi), replace the injector assembly with the lowest fuel pressure drop. Follow injector replacement procedures outlined in the appropriate Service Information Manual for the vehicle.
16. Add one ounce (30 ml) of Fuel System Treatment, P/N 12345104 (Canada P/N 10953467), to the vehicle fuel tank for each gallon (3.78 L) of gasoline estimated to be in the fuel tank. Instruct the customer to add the remainder of the bottle of Fuel System Treatment to the vehicle fuel tank at the next fill-up.
17. Advise customer to change brands of fuel and to add GM Fuel System Treatment every 3000 miles (4800 km). Regular use of GM Fuel System Treatment should keep the customer from having to repeat the injector cleaning procedure.
18. Road test the vehicle to verify that the customer concern has been corrected.
Part Number Description Qty
12346535 GM Top-Engine Cleaner, 24 ml (0.812 oz) Container, U.*. 4
992872 GM Top-Engine Cleaner, 443.6 ml (15 oz) Bottle, Canada 1
12345104 Fuel System Treatment, 591 ml (20 oz) Container, U.*. 1
10953467 Fuel System Treatment, 350 ml (12 oz) Container, (Canada) 1-2
12377900 Dielectric Grease, U.*. 1
10953529 Dielectric Grease Canada 1
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