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3. TESTING PROCEDURE
WARNING! Before using equipment ensure you have read, understood and apply Section 1 safety instructions.
IMPORTANT: The information in this manual is not a substitute for the procedures outlined in the vehicle service manual and fuel
pressure gauge instructions. ALWAYS follow manufacturer's instructions and safety precautions when working on fuel systems.
3.1.
Pre-Test checks.
3.1.1.
Carry out a thorough visual and hands-on inspection of the engine and fuel system. Look for loose or cracked electrical wiring,
battery cables, ignition wires, and fuel or vacuum lines.
3.1.2.
Verify that the battery is fully charged and fuel tank has adequate fuel.
3.1.3.
Verify that the inertia fuel cut-off switch (if fitted) has not been actuated - see vehicle's manual.
3.1.4.
Verify that all fuel system fuses are OK.
3.1.5.
Verify that the fuel vapour recovery system and filler cap are in good condition.
3.1.6.
Verify that the manifold vacuum is within manufacturer's specification (typically 18-20 in.Hg at idle).
3.1.7.
Inspect for fuel leaks and wipe up any spilt fuel immediately.
3.1.8.
Do not take shortcuts. Inspect wiring which may be difficult to see because of location beneath air cleaner housings, alternators, etc.
3.1.9.
Check electrical connectors for corrosion on pins, Bent or damaged pins.
Contacts not properly seated in housing.
Note: Problems with connectors are common in the engine control system - inspect carefully. Note that some connectors use a
special grease on the contacts to prevent corrosion. Do not wipe off! Obtain extra grease, if needed, from your vehicle dealer. It is a
special type for this purpose.
3.1.10.
Check other vehicle systems:
Ignition - for safety reasons, many engine management systems will not deliver fuel without an ignition spark.
3.1.11.
Electronic Control Unit (ECU) - The engine management system ECU has special drivers which energise the fuel injectors. These
drivers are fragile and can easily fail. If an ECU driver problem is suspected, check by replacing the ECU with a known good one
and retest.
3.1.12.
Perform diagnostic procedures as described in the vehicle's service manual to eliminate other possible causes of problems.
Ignition curcuit problems may imitate fuel injection system problems.
3.2.
Testing Injectors visually when removed.
The tester sends a pulse to the fuel injector which forces a spray of fuel from it. To observe the fuel spray pattern, the fuel injector
needs to be removed from the engine either on it's own or all of the injectors with the fuel rail. Please refer to the vehicle
manufacturer's manual for detailed instructions on how to carry this out.
3.2.1.
Turn off the vehicle's engine and ensure the ignition key is in the OFF position.
3.2.2.
Connect the black clip (negative) to the negative terminal of the vehicle's battery and the red clip (positive) to the positive terminal of
the vehicle's battery.
3.2.3.
Carefully disconnect wiring harness from fuel injector to be tested. Note: Do not jerk or pull on wires - some harnesses are attached
with clips. It is a good idea to test injectors in sequence, beginning with cylinder No.1.
3.2.4.
Connect tester to fuel injector. For most injectors it does not matter which wire is connected to which terminal on the injector.
Make sure the injector adaptor wires are securely fastened to the fuel injector terminals and that there is no exposed metal between
them.
3.2.5.
As fuel will be sprayed from the injector and the engine may be hot, it is best to have some form of recepticle to place near the
injector to capture the spray, such as a jam jar or similar.
3.2.6.
Select one of the tester's modes by pressing the MODE SET button, the mode No. will be displayed:
Single Pulse test will test for clogged injectors, Multiple Pulse tests will test for sticky or sluggish injectors.
MODE 1 - LONG - the tester outputs 1 pulse which lasts for approximately 250ms.
MODE 2 - MEDIUM - the tester outputs 50 pulses, each pulse lasts for approximately 7ms.
MODE 3 - SHORT - the tester outputs 100 pulses, each pulse lasts for approximately 3.5ms.
MODE 4 - CONTINUOUS - the tester outputs pulses continuously at the approximate rate of 50 pulses per 1450ms, each pulse
lasts for approximately 7ms. This mode can be cancelled at any time by pressing the MODE SET button again.
3.2.7.
Press the PULSE button to energise fuel injector. The Pulse Indicator will light as injector is energised by the tester.
3.2.8.
Observe for correct spray pattern from the injector and also for leaks from the injector. If necessary, repeat the test by pressing the
PULSE button again.
3.2.9.
If the pulse mode needs to be changed after a test, disconnect the unit from the battery and re-connect it, then select the new
pulse mode, before continuing with a new test.
3.2.10.
When finished testing, replace all injectors and parts.
3.3.
Testing Injectors in conjunction with a fuel pressure gauge.
IMPORTANT: Read and follow all pre-test checks, safety instructions, and fuel pressure testing procedures contained in this
document and in the vehicle's service manual.
WARNING! Always use caution when working around fuel systems. The fuel in the fuel rail may be pressurized even if
the engine is not running. Use a rag to cover the schrader valve or fitting whenever opening the fuel system to attach gauge.
Clean all fuel spills immediately.
3.3.1.
Depressurise the fuel system by following the procedure outlined in the vehicle service manual. On most vehicles, this involves
disconnecting or deactivating the electric fuel pump(s) and operating the engine until it stalls. Note: Some vehicles may have more
than one fuel pump - deactivate all fuel pumps. Failure to do so can result in personal injury, vehicle damage, spilt fuel, fire or other
hazardous conditions.
3.3.2.
Connect a fuel pressure gauge to the fuel line. Some vehicles have a schrader valve located on the fuel rail for this purpose. On
vehicles without a schrader valve, the fuel line must be opened at the appropriate point to insert a fuel pressure gauge adaptor.
Open fuel line at point specified in vehicle service manual. Connect adaptor to fuel line. Attach fuel pressure gauge to adaptor and
tighten fitting until finger tight.
3.3.3.
Test for fuel system leaks.
3.3.4.
Re-pressurise fuel system by cycling vehicle's ignition 'ON' and 'OFF' every ten seconds, until fuel pressure is up to the vehicle
manufacturer's specification - check the vehicle's service manual.
Note: Check fuel pressure gauge connection points for leaks. If leak occurs, clean all fuel spills immediately and check all fittings for
tightness.
3.3.5.
Observe pressure gauge for 10 -15 seconds, looking for pressure drop.
3.3.6.
If the pressure does not drop, continue with fuel injector testing. If fuel pressure does drop, continue looking for leaks by blocking off
the return line between the fuel pressure regulator and the fuel tank. Re-test as described above.
3.3.7.
If the pressure drops again, there may be one or more leaky injectors. Later tests will identify malfunctioning injectors.
Original Language Version
VS211.V2
Issue: 1 - 28/06/10
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