Mazda MX-5 1990 Workshop Manual page 162

F
TROUBLESHOOTING GUIDE -
DIAGNOSTIC INDEX
No. TROUBLESHOOTING ITEM DESCRIPTION
PAGE
1 Will not crank or cranks slowly Refer to Engine Electrical System G- 4
2 Cranks normally but will not start Engine cranks at normal speed but shows no sign of F-20
(No combustion) "firing"
3
Cranks normally but will not start Engine cranks at normal speed but shows partial F-22
(Partial combustion) - When engine is cold combustion and will not continue to run
4
Cranks normally but will not start Engine cranks at normal speed but shows partial F-24
(Partial combustion) - After warm-up combustion and will not continue to run after running
and hot soaked
5
Cranks normally but hard to start - Always
Engine cranks at normal speed but requires exces-
F-26
sive cranking time (more than 5 sec.) before starting
6 Cranks normally but hard to start Same condition as No.5 when engine is cold F-28
- When engine is cold Restarts OK after warm-up
7 Cranks normally but hard to start Same condition as No.5 after running and hot soaked
F-29
- After warm-up Starts normally when cold
8 Rough idle - Always Engine vibrates excessively at idle in every condition F-30
9
Low idle speedlRough idle
Engine speed low or engine vibrates excessively at
F-32
- Before warm-up
idle during warm-up
10
Low idle speedlRough idle - After warm-up Engine runs normally at idle during warm-up but F-34
vibrates excessively after warm-up
11
High idle speed - After warm-up Engine idle excessive for operation mode F-36
12
Low idle speed Engine speed decreases at idle when AIC, PIS, or F-38
- When AIC, PIS, or ElL ON
ElL is ON
13
Rough idle just after starting Engine starts normally but vibrates excessively only
F-39
just after starting
14
Idle moves up and down Engine speed up and down periodically at idle F-40
15
Engine stalls at idle - Always Engine starts normally but vibrates excessively and
F-42
stalls at idle in every condition
16 Engine stalls at idle - Before warm-up
Engine starts normally but vibrates excessively and
F-44
stalls at idle before warm-up
17
Engine stalls at idle - After warm-up Engine runs normally at idle during warm-up but be- F-45
comes rough and stalls after warm-up
18
Engine stalls during start-up Engine unexpectedly stops running while starting F-46
19
Engine stalls on deceleration Engine unexpectedly stops running while decelerat- F-48
ing or after deceleration
20
Engine stalls at idle Engine unexpectedly stops running at idle when AIC, F-50
- When AIC, PIS, or ElL ON PIS, or ElL is ON
21
Engine stalls suddenly (Intermittent) Engine intermittently stops running F-51
22 HesitateslStumbles on acceleration
Flat spot occurs just after accelerator is depressed or
F-52
mild jerking occurs during acceleration
23
Surges while cruising Unexpected, usually repetitive change in engine F-54
speed
24 Lack of power
Performance poor under load F-56
Maximum speed reduced
25
Poor acceleration Performance poor while accelerating F-60
26
Runs rough on deceleration/Backfire Engine runs rough while decelerating and abnormal F-64
combustion in exhaust system
27 Knocking Abnormal combustion accompanied by audible
F-66
"pinging" noise
28 Fuel odor Gasoline odor in cabin
F-68
29
Exhaust sulfur smell Exhaust gas smells abnormal (rotten egg smell)
F-69
30
High oil consumption Oil consumption excessive
F-69
31
Poor fuel economy Fuel economy unsatisfactory
F-70
F-18