Surges/Chuggles
Checks
| Action
|
DEFINITION: Engine power variation under steady throttle or cruise. Feels like
the vehicle speeds up and slows down with no change in the accelerator pedal position.
|
Preliminary
|
| • | Verify that the engine control module (ECM) grounds are clean, tight,
and in the correct locations. |
| • | Make sure the driver understands the operation of the transmission torque
convertor clutch (TCC) and the A/C compressor operation as explained in the owner's
manual. Inform the customer how the TCC and the A/C clutch operate. |
|
Sensor/System
| Test the oxygen sensor (O2S). The O2S should respond quickly to a change in
throttle position. If the O2S does not respond to different throttle positions, inspect
for contamination from fuel, silicon, or the incorrect use of RTV sealant. The sensor
may have a white powdery coating and result in a high, but false, signal voltage,
which gives a rich exhaust indication. The ECM reduces the amount of fuel delivered
to the engine, causing a driveability condition.
|
Fuel System
|
| • | Verify that the fuel injector harness is connected to the correct injector/cylinder
according to the firing order. |
| • | Test or inspect items that can cause an engine to run lean. For a lean
condition, refer to
DTC P0171
. |
| • | Test or inspect items that can cause an engine to run rich. For a rich
condition, refer to
DTC P0172
. |
|
Ignition System
|
| • | Wet down the secondary ignition system with water from a spray bottle.
Wetting down the secondary ignition system may help locate damaged or deteriorated
components. Look/listen for arcing or misfiring as the water is applied. |
| • | Remove the spark plugs and inspect for the following: |
| - | Refer to the following procedures: |
| • | If the spark plugs are fouled by gas, coolant, or oil, determine the cause
before replacing the plugs. Refer to the following procedures: |
| - | For diagnosis of a rich condition, refer to
DTC P0172
. |
| • | Inspect for the correct installation of the ignition coil seals. Incorrect
installation may allow water to enter the spark plug area. Inspect for moisture and
corrosion. |
| • | Inspect the ignition coils and the spark plug boots for cracks or carbon
tracking. |
|
Additional Checks
|
| • | Inspect the vacuum hoses for splits or kinks. Verify that the routing
and connections are correct. |
|
