Daewoo Nubira User Manual page 577

1F – 374IENGINE CONTROLS
EXCESSIVE EXHAUST EMISSIONS OR ODORS
A vehicle fails an emission test. The vehicle has an excessive rotten egg smell.
Important : Excessive odors do not necessarily indicate excessive emissions.
Step
1 Were the Important Preliminary Checks performed?
2
1. Run the engine until it reaches operating tem-
perature.
2. Perform an emission test.
Does the vehicle pass the emission test?
3
1. Connect the scan tool to the Data Link Con-
nector (DLC).
2. Road test the vehicle.
3. Monitor the long term fuel trim memory.
Is the long term fuel trim memory within the value
specified?
4 Is the long term fuel trim memory below the value
specified?
5 Is the long term fuel trim memory above the value
specified?
6
1. Check for a properly installed fuel cap.
2. Check the fuel system pressure.
3. Perform an injector balance test.
Is the problem found?
7
1. Repair or replace any fuel system components
as needed.
2. Perform an emission test.
Does the vehicle pass the emission test?
8
1. Check the ignition system for proper operation.
2. Inspect the spark plugs for excessive wear,
insulation cracks, improper gap, or heavy de-
posits.
3. Check the ignition wires for cracking, hardness,
or improper connections.
Is the problem found?
Action Value(s) Yes
Go toStep 2
System OK
115–150 Go toStep 6
counts
115 counts Go to"Diagnos-
tic Aids for
DTC P0172"
150 counts Go to"Diagnos-
tic Aids for
DTC P0171"
Go toStep 7
System OK
Go toStep 9
No
Go to"Impor-
tant Preliminary
Checks"
Go toStep 3
Go toStep 4
Go toStep 5
Go toStep 8
Go toStep 10
DAEWOO V–121 BL4