Checks
| Action
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Definition: A steady or jerking that follows the engine speed, usually
more pronounced as the engine load increases which 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.
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Preliminary Check
| Refer to
Symptoms
.
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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.
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Engine Mechanical Checks
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| • | Perform a cylinder compression check. Refer to Engine Mechanical. |
| • | Check the engine for the following: |
| - | Broken or weak valve springs |
| • | Check the intake and exhaust manifold passages for a casting flash.
Refer to Engine Mechanical. |
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Fuel System Checks
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| • | Check for water contamination in the fuel. |
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Additional Check
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| • | 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. |
| • | If the problem exists, check the routing of the secondary wires
and the ground circuit. |
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