Mazda MX-5 1990 Workshop Manual page 207

TROUBLESHOOTING GUIDE
F
STEP INSPECTION ACTION
15
Check for correct fuel line pressure at idle Yes Check if fuel line pressure decreases
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page
F-103 when accelerating quickly
Fuel line pressure:
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If decreases, check fuel pump
265-314 kPa (2.7-3.2 kg/cm
2
,
38-46 psi) maximum pressure
L7'
page F-108
(Vacuum hose to pressure regulator dis-
If OK, check fuel line and filter for
connected) clogging
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If no decreases, go to next step
No
Low pressure
Check for fuel line pressure while pinch-
ing fuel return hose
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If fuel line pressure quickly in-
creases, check pressure regulator
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¢ If fuel line pressure gradually in-
creases, check for clogging be-
tween fuel pump and pressure
regulator
If no clogged, check fuel pump
maximum pressure
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16 Run engine several minutes at idle and check if Yes
High pressure
fuel line pressure is held after ignition switch Check if vacuum hose to pressure
turned OFF regulator is damaged or poorly con-
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page F-102 nected
Fuel line pressure: More than 147 kPa
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If OK, replace pressure regulator
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page F-112
(1.5 kg/cm
2
,
21 psi) for 5 min.
e::;>
If not OK, repair or replace hose
PRESSURE
No
Check injector for fuel leakage
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page
F-113
MINIMUM
I ...
.1
IGNITION
5 MIN.
TIME
SWITCH OFF
17 Disconnect each injector connector at idle and Yes Go to next step
check if engine speed decreases equally each
time
No Replace injector
CT
page F-112
18 Try known good ECU and check if condition im-
proves
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page F-127
05UOFX·042
F-63