Checks
| Action
|
DEFINITION: A steady jerking that follows the engine speed,
usually more pronounced as the engine load increases. The vibration is
not normally felt above 1500 RPM or 48 km/h (30 mph).
The exhaust has a steady spitting sound during idle, low speed, or hard
acceleration due to the fuel starvation that can cause the engine to
cut-out.
|
Preliminary Check
| Refer to
Symptoms - Engine Controls
.
|
Ignition System Checks
| Check for a cylinder misfire:
- Start the engine.
- Allow the engine to stabilize.
- Perform the injector balance test.
- If there is no RPM drop on one or more of the cylinders, or if there is an excessive variation in drop, refer to Engine Mechanical Checks in this section.
|
Engine Mechanical Checks
|
| • | Check the engine for the following conditions: |
| - | Broken or weak valve springs |
| • | Check the intake and exhaust manifold passages for a casting flash. Refer toIntake Manifold Cleaning and Inspection and Exhaust Manifold Cleaning and Inspection
in Engine Mechanical -- 6.5L Unit Repair. |
|
Fuel System Checks
|
| • | Check the fuel system for a plugged fuel filter, low fuel pressure, etc. Refer to
Fuel System Diagnosis
. |
| • | Check for water contamination in the fuel. |
|
Additional Check
|
| • | Check for electromagnetic interference (EMI)--The EMI on the reference circuit can cause a missing condition. |
| • | Monitoring the engine RPM with a scan tool can detect an EMI. |
| • | A sudden increase in the RPM with little change in the actual engine RPM will indicate that an EMI is present. |
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