Mazda MX-6 1998, Workshop Manual

Page: 257 / 1282

TROUBLESHOOTING [ENGINE CONTROL KL]
STEP
INSPECTION ACTION
CHECK RESISTANCE OF INJECTOR(S)
AND HARNESS
• Key off.
• Disconnect PCM. Inspect for damaged or
pushed out pins, corrosion, loose wires etc.
Service as necessary.
• Install breakout box. Leave PCM
disconnected.
• Measure resistance between suspect fuel
injector test pin and Test Pin 71 or 97 at
breakout box.
• Is resistance between 12.0— 16.0 ohms?
Yes Fuel injector and harness resistance is okay.
Go to next step.
No Go to step 35 of pinpoint test for DTC P0171, P0172,
P0174, P0175, P1130, P1131, P1132, P1150, P1151,
P1152 step 35 to diagnose fuel injectors.
CHECK INJECTOR DRIVER SIGNAL
Note
• Requires standard 12 volt test lamp.
Properly operating system will show a dim
glow on Test Lamp.
• Key off.
• Breakout box installed.
• Connect PCM to breakout box.
• Connect Test Lamp between Test Pin 71 or
97 and suspect injector test pin.
Yes Go to next step.
Cylinder
Number
Test
pin
Cylinder
Number
Test
pin
1 75 4 100
2
101 5
73
3
74
6
99
No
W6U101WKQ
• Start engine.
• Does test lamp emit dim glow while
No light or bright light.
REPLACE PCM.
REMOVE breakout box.
COMPLETE OBD II Drive Mode.
RERUN OBD Test.
engine is running?
CHECK FUEL PRESSURE
• Key off.
• Install fuel pressure gauge.
• Start and run engine at idle. Record fuel
pressure.
• Increase engine speed to 2,500 rpm and
maintain for one minute. Note and compare
fuel pressure.
• Is fuel pressure between 210— 310 kPa
{2.1— 3.1 kgf/cm2, 31—46 psi}?
Yes Go to next step.
No CHECK fuel system.
CHECK ABILITY OF FUEL SYSTEM TO
HOLD FUEL PRESSURE
• Start and run engine at idle. Note fuel
pressure.
• Increase engine speed to 2,500 rpm and
maintain for one minute.
• Visually check for fuel leaking at injector
O-ring, fuel pressure regulator and fuel
lines to fuel charging component. Service
as necessary.
• Turn engine off.
• Key on, engine off.
• Does fuel pressure remain at
specification within 16.5 kPa {0.16
kgf/cm2, 5 psi} for 60 seconds?________
Yes Go to next step.
No CHECK Fuel Delivery System is at fault.
p r 0 1-14 FUEL INJECTOR INSPECTION, Fuel
Leakage Test
0 1 -0 1 B-51