Century V6-3100 3.1L VIN M SFI (1998)
Fuel Injector: All Technical Service Bulletins
Injector Cleaning Procedure
1.
Remove the J 39021-306, fuel injector test harness, and reconnect the 10-pin fuel rail electrical connector.
Notice:
^
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.
2.
For U.S. 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.
3.
Fill the injector cleaning tank with regular unleaded gasoline. Be sure to follow all additional instructions provided with the tool.
4.
Electrically disable the vehicle fuel pump by removing the fuel pump relay and disconnecting the oil pressure switch connector, if equipped.
5.
Connect the J 35800-A to the vehicle fuel rail.
Notice:
Do not exceed 170 kPa (25 psi). Exceeding this pressure will allow the cleaning solution to flow past the fuel pressure regulator and into the fuel tank
, which may damage the fuel pump and other system components.
6.
Pressurize the J 35800-A to 170 kPa (25 psi).
7.
Remove the vacuum line from the fuel pressure regulator and plug the vacuum hose.
8.
Start and idle the engine until it stalls, due to lack of fuel. This should take approximately 15-20 minutes.
9.
Disconnect J 35800-A from the fuel rail.
10.
Reconnect the vehicle fuel pump relay and oil pressure switch connector, if equipped.
11.
Reconnect the vacuum line to the fuel pressure regulator.
12.
Start and idle the vehicle for an additional 2 minutes to ensure residual injector cleaner is flushed from the fuel rail and fuel lines.
13.
Repeat Steps 1-5 of the Injector Balance Test, and record the fuel pressure drop from each injector.
14.
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.
15.
Road test the vehicle to verify that the customer concern has been corrected.
