Cuts-out & Misses Diagnostics

NOTE: Cut-out and misses issues occur when the engine begins jerking that follows engine speed, usually pronounced as the engine load increases but normally felt below 2,000 RPM. 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.

Checks

Action

Preliminary Checks

N/A

Ignition System Checks

1. Start the engine.

2. Check ignition for proper voltage output with a spark tester.

3. Check for any cylinder misfires.

4. Verify all spark plugged are gapped correctly.

Remove all spark plugs and check for the below conditions:

- burned electrodes

- any and all deposits

- improper spark plug gaps

- any and all wear and tear

Check the secondary ignition for the below conditions:

- ignition wires for arcing and proper routing

- ignition coils for any cracks and carbon tracking

- cross-firing

Engine Mechanical Checks

Perform a cylinder compression check for all cylinders. Check all cylinders for the following conditions:

- worn rocker arms

- worn camshaft lobes

- broken valve springs

- improper valve timing

- improper valve clearance

Fuel System Checks

Check the fuel system for the below conditions:

- low pressure

- plugged filters

Additional Checks

Check the routing for the secondary wires and their ground circuits.

Table 53. Cuts-Out & Misses Diagnostics Table