Suzuki XL7 2007 Service Manual page 827

Circuit/System Description
The scan tool is first used to energize the fuel pump
relay. The fuel injector tester is then used to pulse each
injector for a precise amount of time, allowing a
measured amount of fuel into the manifold. This causes
a drop in system fuel pressure that can be recorded and
used to compare each injector.
Diagnostic Aids
• Monitoring the misfire current counters, or misfire
graph, may help to isolate the fuel injector that is
causing the condition.
• Operating the vehicle over a wide temperature range
may help isolate the fuel injector that is causing the
condition.
• Perform the fuel injector balance test within the
conditions of the customers concern. A fuel injector
condition may only be apparent at a certain
temperature, or under certain conditions.
Reference Information
Connector End View Reference
• "Engine Control Module Connector End Views: "
• "Engine Controls Connector End Views: "
Scan Tool Reference
• "Scan Tool Data List - Engine Controls - 3.6L (LY7): "
• "Scan Tool Data Definitions - Engine Controls - 3.6L
(LY7): "
• "Scan Tool Output Controls - Engine Controls - 3.6L
(LY7): "
Special Tools Required
• J 34730-1A Fuel Pressure Gage
• J 39021 Fuel Injector Coil and Balance Tester
• J 39021-210 Injector Selector Switch Box
• EL-39021-460 Fuel Injector Test Adapter
• J 44602 Injector Test Adapter
Component Testing
Fuel Injector Balance Test with Special Tool
1. Ignition ON, with a scan tool verify that the engine
coolant temperature (ECT) is less than 94°C
(201°F).
➢ If the ECT is greater than 94°C (201°F) allow the
engine to cool before proceeding.
2. Ignition OFF, install the fuel pressure gage. Refer to
"Fuel Pressure Gage Installation and Removal".
3. Ignition ON, verify the fuel pressure is within 380-410
kPa (55-60 psi).
➢ If the fuel pressure is not within the specified range
refer to "Fuel System Diagnosis" for further
diagnosis of the fuel system.
4. Monitor the fuel pressure gage for 1 minute. Verify
that the fuel pressure does not drop more than 34
kPa (5 psi).
➢ If the fuel pressure decreases more than 34 kPa (5
psi) refer to "Fuel System Diagnosis" for further
diagnosis of the fuel system.
CAUTION
!
Do Not repeat any portion of this test before
running the engine in order to prevent the
engine from flooding.
5. Connect the J 39021, J 39021-210, and EL-39021-
460 to the multi-way connector of the fuel injectors,
with the amperage supply selector switch set to the
0.5-2.5 amp position. If the upper intake manifold
has been removed, use J 44602 in place of J 39021-
210 and EL-39021-460, and connect directly to a
fuel injector.
6. Command the fuel pump relay ON with a scan tool
and record the fuel pressure indicated by the fuel
pressure gage after the fuel pressure stabilizes. This
is the first pressure reading.
NOTE
• Repeat this step for each fuel injector in
order to obtain a pressure drop value for
each fuel injector.
• The fuel pressure may rise after the fuel
injector stops pulsing. Record the fuel
pressure value immediately after the fuel
injector stops pulsing. DO NOT record the
higher fuel pressure value.
7. Energize a fuel injector by depressing the Push to
Start Test button on the fuel injector tester. Record
the fuel pressure indicated by the fuel pressure gage
after the fuel injector has stopped pulsing. This is the
second pressure reading.
8. Add all of the individual pressure drop values in
order to calculate the total pressure drop. Divide the
total pressure drop by the number of fuel injectors in
order to calculate the average pressure drop. The
difference between any individual pressure drop and
the average pressure drop should not be more than
20 kPa (3 psi).
➢ If the difference between any individual pressure
drop and the average pressure drop is more than
20 kPa (3 psi), replace the fuel injector.
Repair Instructions
Perform the "Diagnostic Repair Verification - Vehicle
Diagnostic Information: " after completing the diagnostic
procedure.
"Fuel Injector and Fuel Rail Replacement"
Fuel System: 1G-27