DR-24B Check Vacuum Supply From Back Pressure Valve

This test must be performed with engine warm.


1. With engine running, disconnect vacuum gauge from vacuum line and reconnect vacuum line to back pressure valve.
2. Disconnect vacuum line from EGR valve and connect a vacuum gauge to it, then raise engine speed to 2000 RPM.
3. If vacuum gauge shows near the same reading as in Test 24 step A, proceed to Test 24 step C.
4. If vacuum gauge does not show near the same reading as in Test 24 step A, replace EGR/back pressure valve assembly.