Mazda 3 Workshop Manual page 327

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
(See IGNITION COIL INSPECTION
[LF].)
• Is coil resistance normal?
INSPECT MAF PID
• Start the engine.
• Access MAF PID using the WDS or
equivalent.
12
• Race the engine and verify that MAF
PID changes quickly according to
change in the engine speed.
• Is MAF PID response normal?
INSPECT EXCESSIVE AIR SUCTION
IN INTAKE AIR SYSTEM
• Inspect for air leakage at following:
- Between the MAF sensor and
13
throttle body
- Between throttle body and
intake manifold
• Is there any malfunction?
INSPECT FUEL LINE PRESSURE
• Inspect fuel line pressure.
14
(See FUEL LINE PRESSURE
INSPECTION.)
• Is fuel line pressure normal?
INSPECT FUEL LINE FROM FUEL
PUMP TO FUEL DELIVERY PIPE
• Visually inspect fuel line for fuel
15
leakage.
• Is there any fuel leakage?
INSPECT ENGINE COMPRESSION
• Inspect engine compression.
16
(See COMPRESSION INSPECTION
[LF].)
Downloaded from
Yes Go to the next step.
No Replace the MAF sensor, then go to Step 21.
Yes
No Go to the next step.
Yes Go to step 16.
No
Yes Replace suspected fuel line, then go to Step 21.
No
Yes Go to the next step.
No
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Repair or replace suspected part, then go to Step
21.
If the fuel line pressure is too low, go to the next
step.
If the fuel line pressure is excess high, replace
the fuel pump unit, then go to Step 21.
Inspect fuel filters for following:
• Foreign materials or stain inside fuel filter (low-
pressure side)
Perform following actions depend on the result
above.
• If foreign materials or stain is found inside fuel
filter (low-pressure side), clean the fuel tank and
filter (low-pressure side).
• If normal, replace the fuel pump unit.
Then, go to Step 21.
Perform engine overhaul for repairs, then go to
Step 21.
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