Mazda 626 Station Wagon, Workshop Manual

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TROUBLESHOOTING
STEP INSPECTION RESULTS ACTION
4
Is strong blue spark visible at each disconnected
high-tension lead while cranking engine? Yes
Inspect for following:
• Spark plugs malfunction
• Improperly installed CMP sensor
• Trigger wheel damage on camshaft
• Open or short circuit on CMP sensor
• Open or short circuit between CMP sensor
and PCM terminal 8 (for GF4A-EL models)/86
(except for GF4A-EL models) or 85
Repair or replace malfunctioning parts.
If okay, go to next step.
No
Inspect following:
• High-tension leads
• Ignition coil and connector
5 Install fuel pressure gauge between fuel main pipe
and fuel distributor.
Start engine and run it 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—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.
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
Inspect exhaust system.
No Go to next step.
8 Is brake system functioning properly? Yes Go to next step.
No Inspect for cause.
9 Inspect MAF sensor for contamination.
Is there any contamination? Yes Replace MAF sensor.
No
Go to next step.
10 Is engine compression correct? Yes
Inspect for valve timing.
No Inspect for cause.
11 Verify test results. If okay, return to diagnostic index to service any additional symptoms.
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