Mazda RX-8 Operating instructions

ENGINE TROUBLESHOOTING
FOREWORD (w)
•When the customer reports a vehicle malfunction, check the malfunction indicator lamp (MIL)
indication and diagnostic trouble code (DTC), then diagnose the malfunction according to the following
flowchart:
!If a DTC exists, diagnose the applicable DTC inspection. (See DTC TABLE .)
!If no DTC exists and the MIL does not illuminate or flash, diagnose the applicable symptom
troubleshooting. (See QUICK DIAGNOSTIC CHART .)
*: Malfunction Indicator Lamp (MIL), Generator Warning Light, Security Light
(w) RX8-Engine Troubleshooting
Page 1

INTERMITTENT CONCERN TROUBLESHOOTING
Vibration Method
•If a malfunction occurs or becomes worse while driving on a rough road or when the engine is vibrating,
perform the steps below.
NOTE:
•There are several reasons why vehicle or engine vibration could cause an electrical malfunction.
Some of the things to check for are:
!Connectors not fully seated.
!Wiring harnesses not having full play.
!Wires laying across brackets or moving parts
!Wires routed too close to hot parts.
•An improperly routed, improperly clamped, or loose wiring harness can cause wiring to become
pinched between parts.
•The connector joints, points of vibration, and places where wiring harnesses pass such as through
the firewall and body panels are the major areas to be checked.
Inspection Method for Switch Connectors or Wires
1. Connect the WDS or equivalent to the DLC-2.
2. Turn ignition switch to ON position (Engine OFF).
NOTE:
•If the engine starts and runs, perform the following steps at idle.
3. Access the PIDs for the switch you are inspecting.
4. Turn the switch on manually.
5. Shake each connector or wiring harness a bit vertically and horizontally while monitoring the PID.
•If the PID value is unstable, check for poor connection.
(w) RX8-Engine Troubleshooting
Page 2

Inspection Method for Sensor Connectors or Wires
1. Connect the WDS or equivalent to the DLC-2.
2. Turn the ignition switch to the ON position (Engine off).
NOTE:
•If the engine starts and runs, perform the following steps at idle.
3. Access the PIDs for the switch you are inspecting.
4. Shake each connector or wiring harness a bit vertically and horizontally while monitoring the PID.
•If the PID value is unstable, check for poor connection.
Inspection Method for Sensors
1. Connect the WDS or equivalent to the DLC-2.
2. Turn the ignition switch to the ON position (Engine off).
NOTE:
•If the engine starts and runs, perform the following steps at idle.
3. Access the PIDs for the switch you are inspecting.
(w) RX8-Engine Troubleshooting
Page 3

4. Vibrate the sensor slightly with your finger.
•If the PID value is unstable or malfunction occurs, check for poor connection or poorly mounted
sensor or both.
Inspection Method for Actuators or Relays
1. Connect the WDS or equivalent to the DLC-2.
2. Turn the ignition switch to the ON position (Engine off).
NOTE:
•If the engine starts and runs, perform the following steps at idle.
3. Prepare the output state control function for actuators or relays that you are inspecting.
4. Vibrate the actuator or relay with your finger for 3 s after output state control function is activated.
•If a variable click sound is heard, check for poor connection or poorly mounted actuator or both,
or the relay.
NOTE:
•Moving the relays too strongly may result in open relays.
Water Sprinkling Method
CAUTION:
•Indirectly change the temperature and humidity by spraying water onto the front of the radiator.
•If a vehicle is subject to water leakage, the leakage may damage the control module. When testing a
vehicle with a water leakage problem, special caution must be used.
If the malfunction occurs only during high humidity or rainy/snowy weather, perform the following steps:
(w) RX8-Engine Troubleshooting
Page 4

1. Connect the WDS or equivalent to the DLC-2 if you are inspecting sensors or switches.
2. Turn the ignition switch to the ON position (Engine off).
NOTE:
•If the engine starts and runs, perform the following steps at idle.
3. Access the PIDs for sensors or switches if you are inspecting sensors or switches.
4. If you are inspecting the switch, turn it on manually.
5. Spray water onto the vehicle or run it through a car wash.
•If the PID value is unstable or malfunction occurs, repair or replace the part if necessary.
(w) RX8-Engine Troubleshooting
Page 5

ENGINE SYMPTOM TROUBLESHOOTING
•Confirm trouble symptom using the following diagnostic index, then go to the applicable
troubleshooting chart.
Diagnostic Index
No. TROUBLESHOOTING ITEM DESCRIPTION PAGE
1 Melting of main or other fuses  (See NO.1 MELTING OF MAIN O
R
OTHER FUSES .)
2 MIL comes on
The MIL is
illuminated
incorrectly. (No
DTC's)
(See NO.2 MIL COMES ON .)
3 Will not crank The starter does not
work. (See NO.3 WILL NOT CRANK .)
4 Hard to start/long crank/erratic start/erratic crank
The starter cranks the
engine at normal
speed but the engine
requires excessive
cranking time before
starting.
(See NO.4 HARD TO START/LON
G
CRANK/ERRATIC START/ERRAT
I
CRANK .)
5 Engine stalls. After start/at idle
The engine stops
unexpectedly at idle
and/or after start.
(See NO.5 ENGINE STALLS-AFT
E
START/AT IDLE .)
6 Cranks normally but will not start
The starter cranks
engine at normal
speed but the engine
will not run.
(See NO.6 CRANKS NORMALLY
BUT WILL NOT START .)
7 Slow return to idle
The engine takes
more time than normal
to return to idle speed.
(See NO.7 SLOW RETURN TO ID
L
.)
8 Engine runs rough/rolling idle
The engine speed
fluctuates between the
specified idle speed
and lower speed and
the engine shakes
excessively.
(See NO.8 ENGINE RUNS
ROUGH/ROLLING IDLE .)
9 Fast idle/runs on
The engine speed
continues at fast idle
after warm-up.
The engine runs after
the ignition switch is
turned off.
(See NO.9 FAST IDLE/RUNS ON .
)
(w) RX8-Engine Troubleshooting
Page 6

Exhaust afterburn
10 Low idle/stalls during deceleration
The engine stops
unexpectedly at the
beginning of
deceleration or
recovery from
deceleration.
Exhaust afterburn
(See NO.10 LOW IDLE/STALLS
DURING DECELERATION .)
Engine stalls/quits. Acceleration/cruise
The engine stops
unexpectedly at the
beginning of
acceleration or during
acceleration.
The engine stops
unexpectedly while
cruising.
Engine runs rough. Acceleration/cruise
The engine speed
fluctuates during
acceleration or
cruising.
Misses Acceleration/cruise
The engine misses
during acceleration or
cruising.
Buck/jerk Acceleration/cruise/
deceleration
The vehicle
bucks/jerks during
acceleration, cruising,
or deceleration.
Hesitation/stumble Acceleration
A momentary pause
at the beginning of
acceleration or during
acceleration.
11
Surges Acceleration/cruise
A momentary minor
irregularity in engine
output.
(See NO.11 ENGINE STALLS/QUI
T
ENGINE RUNS ROUGH, MISSES,
BUCK/JERK,
HESITATION/STUMBLE, SURGES
12 Lack/loss of power Acceleration/cruise
The performance is
poor under load (e.g.
power down when
climbing hills).
(See NO.12 LACK/LOSS OF POW
E
ACCELERATION/CRUISE .)
13 Knocking/pinging/detonation Acceleration/cruise
Sound is produced
when the air/fuel
mixture is ignited by
something other than
the spark plug (e.g.
hot spot in
combustion chamber).
(See NO.13
KNOCKING/PINGING/DETONATI
O
ACCELERATION/CRUISE .)
14 Poor fuel economy The fuel econom
y
is
(
See NO.14 POOR FUEL ECONO
M
(w) RX8-Engine Troubleshooting
Page 7

unsatisfactory. .)
15 Emission compliance Fails emissions test. (See NO.15 EMISSION
COMPLIANCE .)
16 High oil consumption/leakage The oil consumption
is excessive.
(See NO.16 HIGH OIL
CONSUMPTION/LEAKAGE .)
17 Cooling system concerns Overheating
The engine runs at
higher than normal
temperature/overheats.
(See NO.17 COOLING SYSTEM
CONCERNS-OVERHEATING .)
18 Cooling system concerns Runs cold
The engine does not
reach normal
operating temperature.
(See NO.18 COOLING SYSTEM
CONCERNS-RUNS COLD .)
19 Exhaust smoke
Blue, black, or white
smoke from exhaust
system
(See NO.19 EXHAUST SMOKE .)
20 Fuel odor (in engine compartment) Gasoline fuel smell or
visible leakage
(See NO.20 FUEL ODOR (IN ENG
I
COMPARTMENT) .)
21 Engine noise Engine noise from
under hood (See NO.21 ENGINE NOISE .)
22 Vibration concerns (engine) Vibration from under
hood or driveline
(See NO.22 VIBRATION CONCER
N
(ENGINE) .)
23 A/C does not work sufficiently.
The A/C compressor
magnetic clutch does
not engage when A/C
is turned on.
(See NO.23 A/C DOES NOT WOR
K
SUFFICIENTLY .)
24 A/C is always on or A/C compressor runs
continuously.
The A/C compressor
magnetic clutch does
not disengage.
(See NO.24 A/C IS ALWAYS ON
O
A/C COMPRESSOR RUNS
CONTINUOUSLY .)
25 A/C does not cut off under wide open throttle
conditions.
The A/C compressor
magnetic clutch does
not disengage under
wide open throttle.
(See NO.25 A/C DOES NOT CUT
O
UNDER WIDE OPEN THROTTLE
CONDITIONS .)
26 Exhaust sulphur smell
Rotten egg smell
(sulphur) from
exhaust
(See NO.26 EXHAUST SULPHUR
SMELL .)
27 Fuel refill concerns The fuel tank does
not fill smoothly.
(See NO.27 FUEL REFILL
CONCERNS .)
28 Fuel filling shut off issues The fuel does not shut
off properly.
(See NO.28 FUEL FILLING SHUT
OFF ISSUES .)
29 Spark plug condition An incorrect spark
plug condition.
(See NO.29 SPARK PLUG
CONDITION .)
30 AT concerns Upshift/downshift
engagement
AT concerns not
related to engine
performance.
(See SYMPTOM
TROUBLESHOOTING ITEM TABL
E
(w) RX8-Engine Troubleshooting
Page 8

QUICK DIAGNOSTIC CHART
(w) RX8-Engine Troubleshooting
Page 9

(w) RX8-Engine Troubleshooting
Page 10