Cuts Out/Misses

DEFINITION: A steady or jerking that follows 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 at idle, low speed, or hard acceleration for the fuel starvation that can cause the engine to cut-out.

PRELIMINARY CHECK
Refer to Important Preliminary Checks. Testing and Inspection

IGNITION SYSTEM CHECKS
Check for a cylinder misfire:

1. Start the engine.
2. Allow the engine to stabilize.
3. Perform Injector balance test.
4. If there is no RPM drop on one or more of the cylinders, or excessive variation in drop, refer to Engine Mechanical.

ENGINE MECHANICAL CHECKS

- Perform a cylinder compression check. Refer to Engine Mechanical.
- Check the engine for the following:

- Improper valve timing.
- Bent push rods.
- Worn rocker arms.
- Worn camshaft lobes.
- Broken or weak valve springs.

- Check the intake and exhaust manifold passages for casting flash. Refer to Engine Mechanical.

FUEL SYSTEM CHECKS

- Check the fuel system for a plugged fuel filter, low fuel pressure, etc. Refer to Fuel Supply System Check.
- 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, indicates EMI is present.

If the problem exists, check the routing of the secondary wires and the ground circuit.