Cranks Normally But Hard To Start - When Engine Is Cold - Mazda MX-5 1990 Workshop Manual

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F
TROUBLESHOOTING GUIDE
6 CRANKS NORMALLY BUT HARD TO START - WHEN ENGINE IS COLD
DESCRIP- • Engine cranks at normal speed but requires excessive cranking time before starting
liON - Battery in normal condition
• Restarts OK after warm-up
[TROUBLESHOOTING HINTS]
CD
Air/Fuel mixture too rich
• Airflow meter stuck
• Air cleaner element clogged
-Idle speed control malfunction
@ Air/Fuel mixture too lean
• Fuel injection control malfunction
(Correction for coolant temperature)
@
Poor atomization of fuel
• Low RVP (summer) fuel used in cold weather
STEP
2
3
4
5
6
F-28
INSPECTION
Check if "00" is displayed on Self-Diagnosis
Checker with ignition switch ON
c::::r page F-78
Check if ECU terminal voltages are OK
(1 C, 2D, 20 and 2Q)
c::7
page F-128
Check if engine starts easily when depressing
accelerator while cranking
Check for correct intake manifold vacuum at idle
Vacuum: More than 450 mmHg (17.7 inHg)
~
Check if air cleanerr element is clean
c:r page f-75
Try known good ECU and check if condition
improves
c::::r page F-127
·ACTION
Yes Go to next step
No Malfunction Code No. displayed
Check for cause (Refer to specified
I
check sequence)
"88" flashes
Check ECU terminal
1
F voltage
Voltage: Approx. 12V
(Ignition switch ON)
I
9 If OK, replace ECU I
¢ If not OK, check wiring
betwe~n
ECU and Self-Diagnosis Chec er
I
Yes Go to next step
No Check for cause (Refer to "Check oint
for Each Terminal")
Yes Check if ISC valve is OK
9 If OK, check air valve
c:;>
If not OK, replace ISC valve
No Go to next step
Yes Go to next step
No
Check for air leakage of intake air ys-
tem components
Yes Go to next step
No Replace air cleaner element
Yes Replace ECU
No Change fuel to another brand
c::::r page F-80
c::7
page F-128
c:r page f-127
c::::r page F-7
c::::r page F-131
c::::r page F-99
c:r page f-99
c:r page F-99
c::::r page F-93
c::::r page F-92
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