2005 Chevrolet Silverado 6.6L Eng VIN 2 2500 HD Fuel Injector Balance Test With Tech 2 Scan Tool (With Automatic Transmission).
Circuit Description
The Fuel Injector Balance test is performed when a misfire, knock, excessive smoke, or rough
running condition exists with no electrical DTCs. During the Cylinder
Power Balance portion of the test, the engine control module (ECM)
turns OFF individual injectors while the engine is running and the scan
tool displays engine RPM. The ECM adjusts for the drop in engine speed,
so the power contribution of each cylinder must be felt by the
technician. If a fuel injector is turned OFF and there is a different
power contribution observed when compared to the other cylinders, that
cylinder is identified with the complaint. If the customer complaint
occurs during idle or during offidle tip in acceleration, the balance
rates are used to identify the cylinder with a fault related to the fuel
injector or engine compression. If a fuel injector is turned OFF and
the engine noise or smoke disappears, that cylinder has a fuel injector
or engine compression condition.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
4: The balance rate adjustments are utilized by the ECM only at idle.
The balance rates are the fuel adjustments for each individual cylinder
based on the variations in engine crankshaft speed. A positive value
indicates that fuel is being added to each cylinder event, such as with
poor engine compression or a fuel injector that is not flowing enough
fuel. A negative value indicates fuel being removed from each cylinder
event, such as a fuel injector that is flowing too much fuel. The
balance rates will change depending on if the transmission is in Neutral
or Drive.
5: This step determines if the ECM can control a stable fuel
pressure. A high balance rate may be caused by a fuel injector or
compression only if the ECM can control fuel pressure.
6: The Cylinder Power Balance Test may be performed at any engine
speed or load from idle to wide open throttle (WOT). There is a 5 minute
time limit for each test. The ECM and scan tool must both be powered
down to reset the timer.
Fuel Injector Balance Test with GM Scanner Tech 2 (with Automatic Transmission)
| Step |
Action |
Values |
Yes |
No |
| 1 |
Did you perform the Diagnostic System
Check – Vehicle? |
|
Go to Step 2 |
Go to
Diagnostic
System Check –
Vehicle in
Vehicle DTC
Information |
| 2 |
Are any DTCs set other than P0300, P0301- P0308? |
|
Go to Diagnostic
Trouble Code
(DTC) List –
Vehicle in
Vehicle DTC
Information |
Go to Step 3 |
| 3 |
Does the customer concern occur at idle or during tip-in acceleration off-idle? |
|
Go to Step 4 |
Go to Step 6 |
| 4 |
1. Start and run the engine until the
engine coolant temperature (ECT)
is more than 82°C (180°F).
2. Turn OFF all accessories.
3. Hold the brake pedal in the fully
applied position. A hiss will be
noticeable when the brake is fully
applied.
4. Place the transmission in Drive.
5. Idle the engine for more than 30
seconds.
6. Record the Balancing Rate Cyl.1-8
parameters from the scan tool while
the engine is at idle speed.
7. Repeat steps 2-6 with the
transmission in Neutral.
Are all of the Balancing Rate parameters
within the first specified range in Drive, and
the second specified range in Neutral? |
|
Go to Step 6 |
Go to Step 5 |
| 5 |
Graph the Fuel Pressure Regulator. Refer to Fuel Pressure Regulator Diagnosis .Is the fuel pressure regulator graph normal? |
|
Go to Step 7 |
Go to Step 9 |
| 6 |
IMPORTANT:
The fuel Cylinder Power Balance Test must be performed under the
conditions for which the concern occurred. The concern must be
duplicated during the test. IMPORTANT: DO NOT operate the cruise control
during this test. Cruise control reactivation after the test may cause a
brief extreme increase in engine speed. 1. Observe the cylinder power
contribution or other customer concern. 2. Perform the Cylinder Power
Balance Test in Special Functions.Do any of the cylinders indicate a
different cylinder power contribution than the others, or lessen the
customer concern? |
|
Go to Step 7 |
System OK |
| 7 |
IMPORTANT:
A fuel injector leak into the combustion chamber may result in
mechanical damage to the cylinder. If any fuel spray comes out of a glow
plug hole during the compression test, replace the fuel injector of the
affected cylinder. Perform the Engine Compression test. Refer to Engine
Compression Test in Engine Mechanical – 6.6L.Do any of the cylinders
have low compression? |
|
Go to Symptoms – Engine Mechanical in Engine Mechanical – 6.6L |
Go to Step 8 |
| 8 |
IMPORTANT:
Refer to Injection System Components in Engine Controls Component Views
. Failure to correctly identify the cylinder positions may result in
the replacement of the wrong fuel injector. Replace the fuel injectors
on the cylinders that had poor cylinder power contribution, high balance
rates, or a noise/smoke change. Refer to Fuel Injector Replacement
(Left) or Fuel Injector Replacement (Right) .Did you complete the
replacements? |
|
Go to Step 10 |
|
| 9 |
Replace the fuel pressure regulator. Refer to Fuel Pressure Regulator Replacement. Did you complete the replacement? |
|
Go to Step 10 |
|
| 10 | Operate
the vehicle under the conditions in which the concern occurred.Does the
system operate normally, with no DTCs or symptoms? |
| System OK | Go to
Symptoms –
Engine
Controls |
