Section 03-00: Engine—Service
1994 Mustang Workshop Manual
DIAGNOSIS AND TESTING

Symptom Chart

ConditionPossible SourceAction
  • Difficult Starting
  • Burnt valve.
  • Replace valve.
 
  • Worn piston .
  • Replace piston .
 
  • Worn piston ring(s).
  • Replace piston ring(s).
 
  • Worn cylinder.
  • Service or replace cylinder block .
 
  • Damaged cylinder head gasket .
  • Replace cylinder head gasket .
 
  • Malfunctioning or damaged fuel system.
 
  • Malfunctioning or damaged ignition system.
  • Poor Idling
  • Damaged hydraulic valve tappet .
  • Replace hydraulic valve tappet .
 
  • Improper valve-to-valve seat contact.
  • Replace valve and/or reface valve seat.
 
  • Damaged cylinder head gasket .
  • Replace cylinder head gasket .
 
  • Malfunctioning or damaged fuel system.
 
  • Malfunctioning or damaged ignition system.
  • Abnormal Combustion
  • Damaged hydraulic valve tappet .
  • Replace hydraulic valve tappet .
 
  • Damaged hydraulic valve tappet guide.
  • Replace hydraulic valve tappet guide.
 
  • Burnt or sticking valve.
  • Service or replace valve.
 
  • Weak or broken valve spring .
  • Replace valve spring .
 
  • Carbon accumulation in combustion chamber.
  • Eliminate carbon buildup.
 
  • Malfunctioning or damaged fuel system.
 
  • Malfunctioning or damaged ignition system.
  • Excessive Oil Consumption
  • Worn piston ring groove.
  • Replace piston .
 
  • Sticking piston ring(s).
  • Replace piston ring(s).
 
  • Worn piston or cylinder.
  • Replace piston or cylinder block .
 
  • Worn valve stem seal .
  • Replace valve stem seal .
 
  • Worn valve stem or valve guide.
  • Replace valve stem and guide.
 
  • Leaking oil.
  • Service oil leakage.
  • Engine Noise
  • Excessive main bearing oil clearance.
  • Replace main bearing.
 
  • Seized or heat damaged main bearing.
  • Replace main bearing.
 
  • Excessive crankshaft end play.
  • Replace crankshaft and/or crankshaft thrust main bearing .
 
  • Excessive connecting rod bearing oil clearance.
  • Replace connecting rod bearing .
 
  • Heat damaged connecting rod bearing .
  • Replace connecting rod bearing .
 
  • Worn cylinder.
  • Service or replace cylinder block .
 
  • Worn piston or piston pin .
  • Replace piston or piston pin .
 
  • Damaged piston ring(s).
  • Replace piston ring(s).
 
  • Bent connecting rod .
  • Replace connecting rod .
 
  • Malfunctioning hydraulic valve tappet .
  • Replace hydraulic valve tappet .
 
  • Excessive hydraulic valve tappet clearance.
  • Replace hydraulic valve tappet.
 
  • Broken valve spring .
  • Replace valve spring .
 
  • Excessive valve guide clearance.
  • Replace valve guide and or valve.
 
  • Malfunctioning or damaged cooling system.
 
  • Malfunctioning or damaged fuel system.
 
  • Leaking exhaust system.
  • Service exhaust leakage.
 
  • Improper drive belt tension.
 
  • Malfunctioning generator bearing.
 
  • Loose timing chain.
  • Replace timing chain.
 
  • Malfunctioning water pump bearing.
  • Insufficient Power
  • Malfunctioning hydraulic valve tappet .
  • Replace hydraulic valve tappet .
 
  • Compression leakage at valve seat.
  • Service or replace valve, valve seat and/or cylinder head .
 
  • Seized valve stem.
  • Replace valve and/or guide.
 
  • Weak or broken valve spring .
  • Replace valve spring .
 
  • Damaged cylinder cylinder head .
  • Replace cylinder head gasket .
 
  • Cracked or distorted cylinder head .
  • Replace cylinder head .
 
  • Damaged, worn or sticking piston ring(s).
  • Replace piston ring(s).
 
  • Worn or damaged piston .
  • Replace piston .
 
  • Malfunctioning or damaged fuel system.
 
  • Malfunctioning or damaged ignition system.
 
  • Slipping transmission.
 
  • Dragging brakes.
 
  • Incorrect tire size.
 
  • Restricted exhaust system.