Inspect spark plug
condition.
Is spark plug condition
normal?
No
Specific plug is wet or covered
with carbon:
Go to the next step.
Specific plug looks grayish
white:
Go to Step 7.
All plugs are wet or covered
with carbon:
Go to Step 9.
All plugs look grayish white:
Go to Step 15.
2
Are the spark plug
wet/covered with
carbon by the engine
oil?
Yes
Inspect all areas related to oil,
working up and down.
No
Go to the next step.
3
Inspect the spark plug
for the following:
Cracked insulator
Heat range
Air gap
Worn electrode
Is the spark plug
normal?
Yes
Go to the next step.
No
Replace the spark plug.
(See
SPARK PLUG
REMOVAL/INSTALLATION
[LF]
.)
4
Inspect compression
pressure at suspected
malfunctioning
cylinder.
Is compression pressure
correct?
(See
COMPRESSION
INSPECTION [LF]
.)
Yes
Go to the next step.
No
Repair or replace the
malfunctioning part.
5
Install all spark plugs.
Perform the spark test at
suspected
malfunctioning
cylinder.
Is strong blue spark
visible?
(Compare with normal
cylinder.)
Yes
Go to the next step.
No
Repair or replace the
malfunctioning part.
6
Install the fuel pressure
gauge between fuel
filter and fuel
Yes
Inspect fuel injector for the
following:
2007 Mazda MX-5 Miata Sport
2007 ENGINE PERFORMANCE Symptom Troubleshooting - MX-5 Miata
Microsoft
Thursday, July 09, 2009 2:42:11 PM
Page 115
© 2005 Mitchell Repair Information Company, LLC.
