|
Symptom
|
Definition
|
Possible Causes
|
| Engine will not crank |
Engine will not crank when key is moved to the
start postition. |
- Electrical Fault (starter system)
- Mechanical fault
|
| No start with normal cranking speed |
The starter cranks the engine at normal speed
but the engine does not start. |
- Incorrect air/fuel mixture
- No or insufficient ignition spark
- Engine mechanical problem
|
| Hard starting/ Long cranking time |
The starter cranks the engine at normal speed,
but cranking time excessive |
- Incorrect air/fuel mixture
- No or insufficient ignition spark
- Engine mechanical problem
|
| Low Idle Speed |
Idle speed is lower than normal |
- Incorrect air/fuel mixture
- Idle control problem
- Low engine operating temperature
|
| High Idle Speed |
Idle speed is higher than normal |
- Incorrect air/fuel mixture
- Idle control problem
- Incorrect spark timing
- Vacum leak
|
| Slow to return to Idle |
Engine speed remains high too long when
throttle returned to idle |
- Incorrect air/fuel mixture
- Idle control problem
|
| Rolling/Surging Idle |
Engine speed varies frequently during idle |
- Incorrect air/fuel mixture
- Idle control problem
- Variations on engine load
|
| Engine stalls at idle |
Engine stops running at idle, usually occuring
at stops. |
- Incorrect air/fuel mixture
- Idle control problem
- Low engine operating temperature
- Insufficient ignition spark
|
| Engine Dies |
Engine stops running for no apparent reason
while driving |
- Interruption of ignition spark
- Interruption of fuel supply
|
| Engine is rough |
One or more cylinders consistently causes a
vibration |
- Incorrect air/fuel mixture in one or more
cylinders
- Insufficient ignition spark in one or more
cylinders
- Engine mechanical problem in one or more
cylinders
|
| Hestitaion |
A lag occurs between the time the accelerator
is lightly pushed and acceleration begins |
- Incorrect air/fuel mixture
- Insufficient ignition spark
- Incorrect spark or cam timing
- Low engine temperature
|
| Stumble |
A dropoff of power between the time the
throttle opens more and speed increases. |
- Incorrect air/fuel mixture
- Insufficient ignition spark
- Low engine temperature
|
| Engine Surge |
Engine speed changes while throttle position is
steady |
- Incorrect air/fuel mixture
- Insufficient ignition spark
- Low engine temperature
- Variations on engine load
- Transmission problem
|
| Buck or Jerk |
Sudden lurch occurs due to powerflow
interruption during acceleration. |
- Momentary Incorrect air/fuel mixture
- Momentary Insufficient ignition spark
|
| Lack of Power |
Acceleration is slower than normal or
excessive. Accelerator application needed for
normal driving. |
- Incorrect air/fuel mixture
- Insufficient ignition spark
- Incorrect spark or cam timing
- Restricted air flow( intake or
exhaust)
|
| Ping/Spark Knock |
A series of pinging or rattling or knocking
sounds heard during cruise or acceleration. |
- Incorrect air/fuel mixture
- Insufficient fuel octane
- Excessive compression(carbon)
- Too high engine temperature
- Incorrect spark timing
- EGR system problem
|
| Poor Fuel Economy |
Fuel Consumption is higher than normal |
- Incorrect air/fuel mixture
- Insufficient ignition spark
- Low engine temperature
- Incorrect spark or cam timing
- Engine mechanical problems
- Dragging brakes
|
