Mazda MX-6 1998, Workshop Manual

Page: 87 / 1282

TROUBLESHOOTING [ENGINE CONTROL FSj
STEP
INSPECTION ACTION
6 CHECK CATALYST MONITOR OPERATION
• Key off.
• NGS tester connected.
• Key on, engine on.
• Select PID/DATA MONITOR AND
RECORD and monitor 02S11 and 02S 12
PIDs.
• Drive the vehicle for approximately 10 min.
at 64— 96 km/h {40— 60 mph}.
• Allow vehicle to idle in Neutral or Park.
• Maintain idle engine speed.
• Record PID/DATA and count inversion
times of 02S11 and 02S 12.
• Calculate devide 02S11 by 02S12.
• Is ratio of 0 2 S 1 1 and 0 2 S 1 2 greater than
2.0?
Yes REPLACE PCM.
COMPLETE OBD II Drive Mode.
t
t
After Repair Procedure
RERUN OBD Test.
No REPEAT step.
If ratio of 02S11 and 02S 12 is below 2.0 alter three
attempts, go to next step.
7 CHECK FUEL PRESSURE
Note
• Fuel pressures above specification may
produce abnormally rich air/fuel mixture.
Rich air/fuel mixture may cause higher than
normal catalyst operating temperatures.
• Key off.
• Inspection vacuum hose going to fuel
pressure regulator for proper installation,
cracks, etc. Service as necessary.
• Install fuel pressure gauge.
• Verify vacuum source to fuel pressure
regulator.
• Start and run engine at idle. Record fuel
pressure.
• Increase engine speed to 2,500 rpm and
maintain for one minute. Record fuel
pressure.
• Is fuel pressure between 210 — 310 kPa
{2.2— 3.1 kgf/cm2, 31— 46 psi}?
Yes Fuel pressure is okay.
REMOVE fuel pressure gauge.
Go to next step.
No Fuel pressure is out of specification.
Inspect Fuel Delivery System.
zr 0 1-14 FUEL INJECTOR INSPECTION [FS], Fuel
Leakage Inspection
RESET PCM to completely clear DTCs.
vr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
8 CHECK FOR OBVIOUS LEAK SOURCES IN
EXHAUST SYSTEM
Note
• Catalyst in series with leaking exhaust
system, it can cause Catalyst Efficiency
Monitor Test to fail.
• Key off.
• Inspect following for leaks, cracks, loose
connections or punctures:
• Exhaust manifold
• Front exhaust pipe
• Rear exhaust pipe
• Silencer/tailpipe component
• Are above components free of cracks
and punctures, etc.?
Yes CHECK that exhaust manifold to catalyst inlet pipe joint is
tight.
Go to next step.
No REPLACE/SERVICE the leak source(s).
RESET PCM to completely clear DTCs.
tr After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
9 CHECK FOR OBVIOUS RESTRICTIONS IN
EXHAUST SYSTEM
• Inspect following for dents, areas of
collapsed material and unusual bending:
• Front exhaust pipe
• Rear exhaust pipe
• Silencer/tailpipe component
•
Are above components free of dents
and areas of collapsed material or
unusual bending, etc.?
Yes Go to next step.
No REPLACE/SERVICE restricted component(s) as
necessary.
RESET PCM to completely clear DTCs.
pf- After Repair Procedure
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
01-01A -59