Misfiring Cylinder Test
WARN I N G
DO NOT perform fuel systemmaintenance while smoking or near fire, flames, or sparks.
Fuel may ignite.
Operating personnel must wear fuel-resistantgloves when handling fuels. If exposed to
fuel, promptly wash exposed skin and change fuel-soaked clothing.
Eye protection must be worn when performing this test procedure.
Failure to follow these warnings may result in injury or death to personnel or damage to
C AU T I O N
Use caution to ensure fuel system does notbecome contaminated. Keep work area clean.
Use two line wrenches for removal of injector lines to avoid damage to fittings and
N OT E
Use a container to catch any fuel that maydrain from system. Dispose of fuel IAW local
policy and ordinances. Ensure all spills are cleaned up.
This on-vehicle test can be performed to find acylinder that is misfiring and causing erratic
engine idle and black smoke.
2. While running engine at low idle, loosen fuel line nut at fuel injector nozzle (WP 0042). This will stop flow of fuel
to that cylinder.
3. Listen for change in engine idle speed or for idle to become more erratic.
a. If change occurs, tighten fuel line and proceed to step c.
b. If no change occurs, this cylinder is misfiring.
Repeat steps a and b for each cylinder to be tested.
d. Record results of test.
END OF TASK