Mazda 626 Station Wagon, Workshop Manual

Page: 162 / 577

TROUBLESHOOTING
N0.25 EXHAUST SULPHUR SMELL
25
Exhaust sulphur smell
DESCRIPTION
• Rotten egg smell (sulphur) from exhaust
POSSIBLE
CAUSE
• Electrical connectors are disconnected or connected poorly.
• Charcoal canister malfunction
• Vacuum lines are disconnected or connected improperly.
• Improper fuel pressure
Warning
• Following troubleshooting flow chart contains fuel system diagnosis and repair
procedures. Read following warnings before performing fuel system service:
— Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage.
Always keep sparks and flames away from fuel.
— Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries
or death and damage. Fuel can also irritate skin and eyes. To prevent this, always
complete “BEFORE REPAIR PROCEDURE” and “AFTER REPAIR PROCEDURE”. (See
Section F)
Caution
• Disconnecting/connecting the quick release connector without cleaning it may possibly
cause damage to the fuel pipe and quick release connector. Always clean the quick
release connector joint area before disconnecting/connecting, and make sure that it is
free of foreign material. [
Diagnostic Procedure
STEP INSPECTION RESULTS ACTION
1 Are any drivability or exhaust smoke concerns
present?
Yes Go to appropriate flow chart.
No
Go to next step.
2
Inspect following:
• Electrical connections
• Vacuum lines
Are all items okay?
Yes Go to next step.
No Service as necessary.
Repeat Step 2.
3 Connect NGS tester to DLC.
Turn ignition switch on.
Retrieve any DTC.
Is any DTC displayed?
Yes DTC Is displayed:
Go to appropriate DTC test.
No No DTC Is displayed:
Go to next step.
4 Install fuel pressure gauge between fuel main pipe
and fuel distributor.
Start engine and run it at idle.
Is fuel line pressure correct at idle?
Fuel line pressure
210—260 kPa (2.1—2.6 kgf/cm2, 30—36 psi}
Yes Go to next step.
No Zero or low:
Inspect fuel pump unit circuit.
Inspect for open fuel pump body relief valve.
Inspect for fuel leakage inside pressure
regulator.
Inspect for clogged main fuel line.
High:
Inspect pressure regulator for high pressure
cause.
Inspect for clogged fuel return line.
5 Does fuel line pressure remain within specification
for 60 seconds when ignition switch is turned on?
Fuel line pressure
210—260 kPa {2.1—2.6 kgf/cm2, 30—36 psi}
Yes Go to next step.
No
Inspect pressure regulator for high pressure
cause.
6 Inspect charcoal canister for fuel saturation.
Is excessive amount of liquid fuel present in
canister?
Yes Replace charcoal canister.
No
Inspect fuel tank vent system.
If fuel tank vent system is okay, since sulfur
content can vary in different fuels, suggest trying
a different brand.
If fuel tank vent system is not okay, repair or
replace malfunctioning parts.
F1-141