Check Cylinder Performance

If KOER CYLINDER CONTRIBUTION SELF-TEST under QUICK TEST in TESTS W/CODES - 7.3L DIESEL article has been successfully completed previously, go to CHECK FOR EXHAUST RESTRICTION  . If KOER CYLINDER CONTRIBUTION SELF-TEST has not been completed, perform KOER CYLINDER CONTRIBUTION SELF-TEST. Possible causes for failing this test are:

• Broken compression rings.
• Burnt or bent valve.
• Bent push rods.
• Bent connecting rods.
• Damaged rocker arms.
• Faulty fuel injector assembly.