Mazda MX-5 1990 Workshop Manual page 215

STEP
6
TROUBLESHOOTING GUIDE
INSPECTION
Check if ECU terminal voltages are OK
(20, 2N, 20, 2P, 20, 2U and 2V)
c:::r page F-129
ACTION
Yes Go to next step
No Check for cause (Refer to "Check Point
F
for Each Terminal") c::r page F-132
7
Check if fuel cut operation is OK during de-
celeration
Fuel cut: Above 1,900 rpm after warm-up
8 Check
for
correct ignition timing at idle
c:r page F-75
Ignition timing: 10
0
±
1
0
BTDC
~
bIJ'lhl
CONNECT TERMINALS
Yes Go to next step
No Try known good ECU
Yes Go to next step
No Adjust
9 Check for correct fue/'Iine pressure at idle Yes
Go
to next step
IT
page F-111
Fuel line pressure:
216-265 kPa (2.2-2.7 kg/cm
2
;
31-38 psi)
10 Run engine several minutes at idle and check if
fuel line pressure is held after ignition switch
turned OFF
r:::r
page F-102
Fuel line pressure: More than 147 kPa
(1.5 kg/cm
2 ,
21 psi)
for
5 min.
PRESSURE
MINIMUM
I ..
IGNITION 5 MIN.
.1
TIME
SWITCH OFF
11 Change fuel to another brand
No
High pressure
Check if vacuum hose to pressure
regulator is damaged or poorly con-
nected
c:::> If OK, replace pressure regulator
r:::;>
If not OK, repair or replace hose
Yes Go to next step
No
Check injector for fuel leakage
C7'
page F-127
c:::r page F-75
c::r page F-112
c:::r
page F-113
05UOFX-048
F-71