Skylark V6-3100 3.1L VIN M SFI (1996)
6.
If there is a 20 kPa (3 psi) difference, or less, between the highest and lowest fuel pressure drop, the fuel injectors are operating properly and
further diagnostics should be performed on the vehicle.
Example One
Maximum Difference: 68-41 = 27 kPa (10-6 = 4 psi)
Although the pressure drop is greater than 20 kPa (3 psi), cylinder 2 stands out as being rich when compared to the other injectors. Do not clean the
injectors. Replace injector number 2. Charge time to labor operation J5650.
Example Two
Maximum Difference: 48-23 = 25 kPa (7-3 = 4 psi) The pressure drop is greater than 20 kPa (3 psi). Injectors 1 and 3 appear to be lean when compared
to injectors 2, 4, 5 and 6. Clean and re-test pressure drop. If cleaning does not restore flow on injectors 1 or 3, replace the defective injector or injectors
as necessary. Charge time to labor operation J5650.
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.
