Cranks Normally But Hard To Start - After Warm·up - Mazda MX-5 1990 Workshop Manual

TROUBLESHOOTING GUIDE
F
7
CRANKS NORMALLY BUT HARD TO START - AFTER WARM·UP
DESCRIP·
TION
• Engine cranks at normal speed but requires excessive cranking time (more than 5 sec.) before starting after
running and hot soaked
e Battery in normal condition
• Engine starts normally when cold
[TROUBLESHOOTING HINTS]
CD
Air/Fuel mixture too rich
• Fuel injection control malfunction
elnjector fuel leakage
STEP INSPECTION
Check if "00" is displayed on Self-Diagnosis
Checker with ignition switch ON
L7
page F-78
2 Check if ECU terminal voltages are OK
(20 and 2Q)
3
c:::r page F-129
Run engine at idle and check if fuel line pres-
sure is held after ignition switch turned OFF
c:::r page F-1 02
Fuel line pressure: More than 147 kPa
(1.5 kg/cm
2
,
21 psi) for 5 min.
I
INSTALL CLAMPS
4
Try known good ECU and check if condition
improves
c:::r page F-127
®
Vapor lock
• Fuel pressure not held in fuel line after engine stops
e High RVP (winter) fuel used in warm weather
ACTION
Yes Go to next step
No Malfunction Code No. displayed
Check for cause (Refer to specified
check sequence)
"88" flashes
Check ECU terminal 1 F voltage
Voltage; Approx. 12V
(Ignition switch ON)
c:::r
page F-80
c:::r page F-128
¢
If OK, replace ECU c:::r page F-127
c:;>
If not OK, check wiring between
ECU and Self-Diagnosis Checker
L7
page F-7
Yes Go to next step
No Check for cause (Refer to "Check Point
for Each Terminal") c:::r page F-132
Yes Go to next step
No Block outlet of pressure regulator and
check if fuel line pressure is held after
ignition switch turned OFF c:::r page F-111
¢
If OK. replace pressure regulator c:::::r page F-112
ct> If not OK, check fuel pump hold
pressure c:::r page F-107
If fuel pump is OK, check injector
for fuel leakage c:::r page F-113
Yes Replace ECU
No Change fuel to another brand
05UOFX-024
F-29