Checks
| Action
|
DEFINITION: The
vehicle has a momentary lack of response when depressing the accelerator
pedal. The condition can occur at any vehicle speed. The condition
is usually most severe when attempting to make the vehicle move,
as from a stop sign. The condition may cause the engine to stall
if it is severe enough.
|
Preliminary Checks
| Refer to Important Preliminary Checks in
Symptoms - Engine Controls
.
|
Fuel System Checks
|
| | Inspect for low pressure during moderate or full throttle acceleration.
If the fuel pressure drops below specification, there is possibly a low
or high pressure regulator fault or a fuel system restriction. |
| • | Test for proper EVAP purge system operation. |
| • | Inspect for proper installation of the bonnet and fuel mixer. |
| • | Inspect for air leaks at the mixer. |
|
Sensor Checks
|
| • | Test for proper TP sensor operation. A TP sensor that does not
respond quickly and accurately to throttle plate movement may cause this
symptom. |
| • | Test for proper MAP sensor operation. A MAP sensor that does not
respond quickly and accurately to manifold pressure changes may cause
this symptom. |
|
Ignition System Checks
|
| | Important:: A higher secondary ignition voltage is required to operate the vehicle
on CNG than on gasoline. A vehicle that operates normally on gasoline
does not indicate a fully functional ignition system.
|
| • | Check for proper secondary ignition system voltage output using ONLY
the J 26792
spark tester. |
| • | Inspect for fouled spark plugs. |
| | If fouled spark plugs are indicated the reason for the fouling must
be found and corrected. |
| • | Test for faulty spark plug wires. |
| • | Test for an open ignition system ground, if equipped. |
|
Additional Checks
|
| • | Review service bulletins for control module programming updates
for the Alternative Fuels ECM and the PCM. |
| • | Inspect for manifold or air induction system leaks. |
| • | Test for proper generator operation. |
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