Intake and Exhaust Restriction
Figure 1. Diagnostic Form
A visual inspection of the intake/exhaust restriction will determine if this component is contributing to a no start or hard start condition. For a reproduction of the applicable portion of the diagnostic form, see Figure
Note: A high intake or exhaust restriction may cause a considerable amount of black or blue smoke when starting the engine.
Inspection of Intake and Exhaust Restriction
Use the following procedure to visually inspect the intake/exhaust restriction:
- Air cleaner inlet and ducting to assure that it is not restricted or collapsed.
- Air cleaner housing, filter element and gaskets for proper installation.
- Filter-minder to assure the intake restriction is below 25 inches H2
O. When the filter element reaches maximum allowable restriction, the yellow indicator reaches the top of the window and automatically locks in this position. See Figure
- Exhaust system for damaged or restricted pipes.
Figure 2. Low Restriction
Figure 3. High Restriction
Possible causes for the hard start/no start diagnosis include the following:
- Snow, plastic bags or other foreign material may restrict air flow at the air cleaner inlet. On engines recently repaired, rags or cap plugs may have been inadvertently left in the intake system.
- The tailpipe or muffler may have been damaged or collapsed.
- Restricted catalytic converter (if equipped).
|Series 40E Troubleshooting Manual – 6SE241|
|Generated on 10-13-2008|