Fuel Injector Bench Test

1. Check that the manual shut off valve, located at rear of panel, is OFF.

2. Fill the cleaner/tester fuel tank to the lower fill line with clean fresh gasoline.

3. Connect the fuel supply hose to the fuel injector being tested.

4. Connect the number 1 tester harness connector to the fuel injector. Turn the injector selector switch to number 1 position.

5. Direct the injector nozzle into the fuel tank.

6. Connect power supply leads to the battery, observing correct polarity.

7. Press power and timer switches to ON. Check for leaks.

8. Press the purge switch for about 30 seconds to eliminate air from the supply hose and injector.

9. Leakage from the fuel injector nozzle tip should be visible. Replace any leaking injector.

10. If the injector passes the leakage test, press the appropriate test button: Amber - standard injector; White - turbo injector. Check the flowmeter readings, and record all test-results.

MILLER SPECIAL TOOL WARRANTY
The EFI Fuel Injector Cleaner/Tester, P/N MST 4743 C/T, carries a one-year warranty from the manufacturer, Miller Special Tools, 32615 Park Lane, Garden City, Michigan. Miller Special Tools will repair or replace parts as required. Do not open, inspect or adjust the electronic control box. In case of malfunction, the District Service Manager, the Regional Technical Information Coordinator or Miller Special Tools should be called for assistance.
NMC SERVICE AND PARTS WARRANTY POLICY
Fuel injector cleaning is not covered by warranty, since clogged or dirty fuel injectors are not considered defective in material or workmanship. Dirty injectors will not be a cause for replacement under warranty. However, when the fuel injectors fails the test due to high flowmeter readings, or due to leakage, the injectors will be replaced under the following conditions:

1. The injectors must be tested and the results indicated on the warranty return tag.

2. Only leaky or high flow injectors will be considered for warranty replacement.

3. Returned injectors will be tested at NMC.

This policy will be effective upon receipt of the Fuel Injector Cleaner/Tester equipment.


Laminated copies of instructions and procedures (refer to following pages) are furnished with each cleaner/tester stand.
FUEL INJECTOR TESTING PROCEDURE
MODEL MST 4743 C/T

When Test is Performed Before Cleaning



1. Turn manual shut off valve at the back of test stand panel to OFF position (See Fig. 1).

2. Pour clean gasoline into the tester fuel tank and fill to LOWER FILL LINE (Fig. 1). Reinstall fuel tank cap snugly and back off one turn,





3. Disconnect vehicle fuel hose between fuel filter and fuel injector loop at the fuel inlet. Connect the supply hose from testing equipment to the fuel inlet (Fig. 2).

4. Disconnect vehicle return hose from fuel return line. Plug the return line. Install the U-Tube (supplied) between the vehicle fuel supply hose and the fuel return hose (Fig. 2).
5. Install the turnbuckle (supplied) loosely between throttle control rod and suitable hookup point on car fender wall.





6. Connect power supply line to car battery (red terminal-positive; black terminal-negative). Turn power switch ON (red button). Activate 10-minute timer (green button) (Fig. 3). Start the engine and check for leaks.





7. When the engine speed has stabilized (warm up period), set the idle speed to 2000 rpm with the turnbuckle. Check that the pressure gauge reads 35 psi (pre-set at the factory). If pressure requires adjustment, loosen lock nut and turn adjustment lever (Fig. 1), until 35 psi is obtained. Retighten lock nut.
8. After the fuel pump and the engine shut off automatically in 10 minutes, turn ignition switch to OFF position.


9. Install the tester injector harness on the vehicle injectors. Observe injector number on the harness connector to match cylinder number.

NOTE Using hose pliers, pinch off fuel line at vehicle's pressure regulator to prevent fluctuation of float during testing.





10. Actuate 10-minute timer. Position injector selector switch to each injector number while pressing fuel injector test button (Amber-standard injector, White-Turbo Injector). (See Fig.3).





11. Observe the position of the flowmeter float at eye level. A float level with 0 to 10 range on the scale indicates a good injector. Acceptable injector performance range is between the lower and upper red line.

NOTE.1) When flowmeter reading is on lower red line or below, the fuel injector should be cleaned.

2) When the flowmeter reading is on upper red line or above, the injector should be replaced.
12. To confirm initial test readings, a maximum of 3 testings on the set of injectors can be performed before restarting the engine.

NOTE: If all readings are high, there may be leaky injectors (one or more). To check for leaky injectors, observe pressure gauge. It should hold pressure with the fuel pump off. Note: If there is a pressure drop, remove all injectors and test individually. Refer to Technical Bulletin No. TS82-075 for Bench Testing Procedure.

13. Turn power switch OFF and disconnect power supply. Reinstall vehicle fuel lines. Start the engine and check for leaks.

NOTE:If fuel injector cleaning is required, turn manual shut off valve to the ON position. Refer to Fuel Injector Cleaning Procedure.

NOTE Testing may be performed before or after cleaning process.