Mazda MX-6 1998, Workshop Manual

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TROUBLESHOOTING [ENGINE CONTROL KL]
STEP
INSPECTION
ACTION
5 Install fuel pressure gauge between fuel filter
and fuel distributor.
Start engine and run at idle.
Measure fuel line pressure at idle.
Is fuel line pressure correct at idle?
Fuel line pressure
210— 260 kPa
{2.1— 2.6 kgf/cm2, 30— 37 psi}
Yes Go to next step.
No
Zero or low:
Check fuel pump circuit.
Check for open fuel pump relief valve.
Check for fuel leak inside pressure regulator.
Check for clogged main fuel line.
High:
Check pressure regulator for high pressure cause.
Check for clogged fuel return line.
6
Remove and shake PCV valve.
Does PCV valve rattle?
Yes Go to next step.
No Replace PCV valve.
7 Is there restriction in exhaust system? Yes Check exhaust system.
No Go to next step.
8 Is brake system functioning properly? Yes Go to next step.
No
Check for cause.
9 Check for contaminated MAF sensor.
Is there any contamination?
Yes Replace mass air flow sensor.
No Go to next step.
10 Is engine compression correct?
s t
01 -10B COMPRESSION INSPECTION
[KL]
Yes Check for valve timing.
No Check for cause.
11 Verify test results. If okay, return to diagnostic index to service any additional symptoms.
14 EMISSION COMPLIANCE
DESCRIPTION
Emission compliance test is failed
POSSIBLE
CAUSE
• Vacuum lines leaks or blockage
• Spark plug malfunction
• Erratic or no signal from camshaft position sensor
• PCV valve malfunction or incorrect valve installation
• Exhaust system clogged
• Charcoal canister damage
• Improper engine compression
• Cooling system malfunction
• Leaks from intake manifold
• Inadequate fuel pressure
• EGR valve malfunction
• Fuel tank ventilation system malfunction
• Excessive carbon build up in combustion chamber
• Improper valve timing
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 leaks 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” described in this manual.
s t
0 1 -1 4 BEFORE REPAIR PROCEDURE
s t
0 1 -1 4 AFTER REPAIR PROCEDURE
STEP INSPECTION ACTION
1 Check following:
• Vacuum lines for leaks or blockage.
• Electrical connections.
• Proper maintenance schedule followed.
• Intake air system and air cleaner element
concerns; such as obstructions, leaks or
dirty.
Are all items okay?
Yes Go to next step.
No Service as necessary.
Repeat step 1.
0 1 -0 1 B -1 56