Series 40E Troubleshooting – Section 11.16 Exhaust Restriction

Figure 1. Diagnostic Form

The following procedure will lead you through the Exhaust Restriction Test. For a reproduction of the applicable portion of the diagnostic form, see Figure
“Diagnostic Form”

. ‪

Section 11.16.1
Purpose

This test will determine if an excessive restriction exists in the exhaust system that would cause an engine performance problem.‪

Section 11.16.2
Test Procedure

Follow these steps to test for an excessive exhaust restriction:‪

1. Drill and braze on a 1/8 in. NPT male connector in a straight section of exhaust pipe, approximately 3 to 6 in. after the bend in the exhaust pipe. See Figure
   “Exhaust Back Pressure Test Location”.
   

   1. Exhaust Elbow‪	4. Drill and Braze on Connector‪
   2. Turbine‪	5. Water Manometer or Magnehelic Gage‪
   3. Exhaust Pipe‪	‪

   Figure 2. Exhaust Back Pressure Test Location

2. Connect a minimum of one foot coiled copper tubing to the connector before attaching the plastic tubing from the Gage Bar.Note: The coiled copper tubing prevents the plastic tubing from melting.
3. Connect the other end of the plastic tubing to the magnehelic gage on the Gage Bar or a water manometer.
4. Obtain the data at rated speed on a chassis dynamometer or fully loaded on the highway. The engine must be at normal operating temperature.
5. Pressures that exceed specification indicate a restriction in the exhaust system that can cause a reduction in engine power. Reduce restriction by replacing the muffler or exhaust piping as required.

Section 11.16.3
Possible Causes

The following conditions are possible causes of exhaust restriction:‪

• Collapsed exhaust piping
• Restricted exhaust piping
• Damaged muffler

Section 11.16.4
Tools Required

Engine Field Test Kit, J 39257
, or a water manometer‪