Fuel Injector - Testing and Cleaning
BULLETIN NUMBER ISSUE DATE GROUPSB86-02-005 August 1, 1986 FUEL
FIGURE 1:
VEHICLES AFFECTED
All Impulse (JR) models.
SERVICE INFORMATION
Affected vehicles may exhibit engine hesitation caused by fuel injector clogging and/or the buildup of
fuel/combustion deposits in the induction system. Figure 1 is a diagnosis chart for this situation. This Service Bulletin outlines two new service procedures mentioned in the diagnosis chart: injector testing and injector cleaning.
FIGURE 2 - FUEL LINE CLAMP:
SERVICE PROCEDURE
WARNING
These service procedures involve opening fuel system lines. Be sure to have an approved fire extinguisher available at all times.
Injector Testing
1. Disconnect the battery ground cable.
2. Loosen the fuel line clamp shown in Figure 2. Using a shop cloth to catch any spilled fuel, remove the fuel line from the fitting. Safely dispose of the shop cloth.
FIGURE 3 - FUEL INJECTOR TESTER:
3. Connect the fuel injector tester fuel line to the exposed fitting and secure it with a screw-type clamp. See Figure 3. Connect the tester fuel line tee fitting to the engine fuel line.
4. Connect the fuel injector tester gauge to the tee fitting. See Figure 3.
5. Reconnect the battery ground cable.
6. Place the open end of the tester gauge relief line into a container suitable for gasoline. Open the tester gauge relief valve. See Figure 3.
FIGURE 4 - FUEL PUMP RELAY CONNECTOR:
7. Remove the relay box cover and operate the vehicle's fuel pump by connecting a jumper wire between the battery positive terminal and the white/ black (turbo) or black/red (non-turbo) wire terminal
on the fuel pump relay. See Figure 4. Run the fuel pump until fuel flows through the tester gauge relief line and all air is expelled. Close the relief valve and stop the fuel pump.
FIGURE 5 - I-TEC HARNESS CONNECTOR:
8. Disconnect the I-TEC harness connector. This is a 9-pin connector containing 8 wires. See Figure 5. Note that all test connections will be made on the engine side of the connector.
9. Disconnect the dropping resistor connector. This is a 6-pin connector containing 5 wires. See Figure 5. Note that all test connections will be made on the engine side of the connector.
FIGURE 7 - FUEL INJECTOR TESTER:
NOTE
Charts the connections described in Steps 10-15.
10. Connect the fuel injector tester control box to the engine as follows (Figure 7):
a. Clamp the power leads to the vehicle's battery terminals (red to positive, black to ground).
b. Plug the tester's male lead into the red/white wire terminal in the dropping resistor connector.
c. Plug the tester's female lead into the white/black wire terminal in the I-TEC harness connector. This set-up will test injector No. 1.
TESTER CONTROL BOX
MALE LEAD TO DROPPING FEMALE LEAD TO I-TEC TO TEST
RESISTOR CONNECTOR HARNESS CONNECTOR INJECTOR
Red/White White/Black #1
Red White #2
Red/Blue White/Blue #3
Red/Yellow White/Red #4
11. Observe the fuel injector tester gauge. Using the jumper wire, operate the vehicle's fuel pump for 5 seconds. When the jumper wire is removed, fuel pressure should drop slightly and then stabilize. Record the stabilized reading on the Repair Order.
NOTE If the fuel pressure will not stabilize, check the following fuel leakage points as described in the appropriate Workshop Manual:
a. Fuel pump.
b. Pressure regulator.
c. Fuel injectors.
d. Fuel lines.
12. Press the button on the fuel injector tester control box. This operates one fuel injector. Fuel pressure will drop, then climb slightly. Record the lowest pressure reading on the Repair Order. The difference between this reading and the pressure recorded in Step 11 is the pressure drop for that injector.
13. Move the tester's male lead to the red wire terminal. Move the female lead to the white wire terminal. This set-up will test injector No. 2. Repeat Steps 11 and 12.
14. Move the tester's male lead to the red/blue wire terminal. Move the female lead to the white/blue wire terminal. This set-up will test injector No. 3. Repeat Steps 11 and 12.
15. Move the tester's male lead to the red/yellow wire terminal. Move the female lead to the white/red wire terminal. This set-up will test injector No. 4. Repeat Steps 11 and 12.
16. Compare the recorded pressure drops. The smallest pressure drop should be within 10% of the greatest drop. For example, if the greatest pressure drop is 16 psi, the smallest pressure drop should be within 1.6 psi-no less than 14.4 psi. A pressure drop variation of more than 10% indicates that one or more injectors are clogged or sticking.
17. Remove the injector tester control box and fuel pump relay jumper from the vehicle. Reconnect the dropping resistor and I-TEC harness connectors. If the injectors failed the test, leave the relay box cover off; otherwise, install it.
18. Disconnect the battery ground cable.
19. Relieve fuel system pressure by opening the tester gauge relief valve. Disconnect the gauge from the tee fitting. If the injectors failed the test, leave the tester fuel line and tee fitting in place. Otherwise, remove the tester fuel line and tee fitting, reconnect original fuelline, reconnect the battery ground cable and check for fuel leaks.
Injector Cleaning
NOTE
Observe all storage and handling precautions supplied with the cleaner assembly. Use the cleaner according to the procedure in this Service Bulletin, even if it conflicts with operating instructions packed with the cleaner assembly.
1. Disconnect the battery ground cable if you haven't already done so.
2. Pour 1/2 gallon of cleaning solution into the cleaner tank. The cleaning solution consists of 1 gallon unleaded gasoline mixed with a 20 oz. container of Chevron Techron Gasoline Additive.
FIGURE 8 - INLINE VALVE:
3. Make sure the inline valve on the cleaner tank fuel line is closed. See Figure 8. Connect the tank fuel line to the tee fitting installed in Step 2 of Injector Testing.
4. Operate the cleaner tank pump to pressurize the tank to 25 psi.
5. Open the inline valve on the cleaner tank fuel fine 1/2 turn.
6. Pull the connector from the vehicle's fuel pump relay.
7. Reconnect the battery ground cable.
8. Start and run the engine at 2,000 rpm for 20 minutes. The engine will draw the fuel/cleaning solution from the cleaner tank. After 20 minutes, stop the engine.
9. Close the inline valve on the cleaner tank fuel line. Disconnect the fuel line from the tee fitting.
10. Reconnect the fuel pump relay connector. Start and run the engine for 5 minutes to purge all cleaning solution from the system. Repeat the Injector Testing procedure described in this Service Bulletin. If one or more injectors still fail the test, the clogged injector(s) should be replaced.
NOTE
All cleaning solution must be purged before the injectors are tested or test results will be inaccurate.
11. Disconnect the battery ground cable.
12. Remove the tee fitting and fuel line from the engine. Reconnect the original fuel line.
13. Reconnect the fuel pump relay connector. Install the relay box cover.
14. Reconnect the battery ground cable. Start the engine and check for fuel leaks.
SPECIAL TOOL INFORMATION
The following special tools will be shipped directly to all dealers:
Part No. Description
J-35957 Injector Test Kit
J-35800 Fuel Injector Cleaner
PARTS INFORMATION
Part No. Description
2-91012-600-0 Gasoline Additive (case of 12,
20 oz. containers)
WARRANTY INFORMATION
OPER.
OPERATION TASK SPEC. I-MARK I-MARK IMPULSE
NUMBER INSTR. (PF) (JT) (JR)
020299 INJECTOR TESTING - - - .8
AND CLEANING
Includes: Retest if required.
020285 INJECTOR Repl. *Auth. - - 1.1
*Authorization required Emis.
to replace 2 or more injectors under this operation number
Trouble Code: 71
Parts: Dealer cost + 25% (maximum one 20 oz. container Techron per cleaning operation)