Vehicle applicability: This diagnostic supplement covers multiple Ford vehicles and engines. Follow the application named in the source below. Some references apply to vehicles other than Mustang.
REPAIR as necessary. Clear the PCM DTCs. CARRY OUT the catalyst monitor drive cycle to verify the repairs. | GO to HF10 . |
HF6 CHECK FOR RESTRICTIONS IN THE EXHAUST SYSTEM
Note: A slight pressure in the exhaust system is normal, but excessive exhaust back pressure seriously affects engine operation.
• Inspect the following for damage or restrictions:
◾ front and rear exhaust pipes ◾ catalytic converter ◾ muffler and tailpipe assembly
Is a concern present?
Yes | No |
|---|---|
REPAIR as necessary. Clear the PCM DTCs. REPEAT the self-test. | GO to HF7 . |
HF7 CHECK FOR EXCESSIVE EXHAUST BACK PRESSURE
• The internal condition of exhaust system and its ability to flow can be checked with an exhaust back pressure tool.
Is an exhaust back pressure tester available?
Yes | No |
|---|---|
GO to HF8 . | GO to HF9 . |
HF8 CHECK FOR EXCESSIVE EXHAUST BACK PRESSURE WITH EXHAUST BACK PRESSURE TOOL
Note: Typical exhaust back pressure, when measured near the exhaust manifold and at normal engine operating temperature, should not exceed 20.7 kPa (3 psi) at idle and 55.2 kPa (8 psi) at wide open throttle (WOT) under load.
• Install an exhaust back pressure tester and follow the tool manufacturer installation and testing instructions.
Does the exhaust back pressure test indicate a restriction?
Yes | No |
|---|---|
REPAIR as necessary. Clear the PCM DTCs. REPEAT the self-test. To continue diagnosis of a symptom (lack of | No indication of restrictions or leaks has been detected in the exhaust system. To continue diagnosis of a symptom (lack of power, loss of power, or no start), REFER to Section 3 , Symptom Charts. |
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.