Mazda MX-5 1990 Workshop Manual page 177

TROUBLESHOOTING tiU·IDE
STEP INSPECTION
6 Connect System Selector to diagnosis connector
and set Test Switch to "SELF TEST" when en-
gine is cold
Check if engine speed decreases as engine
warms up
cr
page F-98
- -
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7 With condition of Step 5 check for correct igni-
tion timing at idle after warm-up
cr
page
F-75
Ignition timing: 10 0
:±:
1 0 BTDC
8 Try known good ECU and check if condition
improves
Yes Go to next step
No Check air valve
Yes Go to next step
No Adjust
Yes Replace ECU
ACTION
c::::7'
page
F-127 No Change fuel to another brand
F
c:::r page F-99
cr
page F-75
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page F-127
05UOFX·026
F-33