1987 MAZDA 626 Workshop Manual

TROUBLESHOOTING 7C
Procedure
76G07C-025
1. Connect a tachometer to the engine.
2. Shift the selector lever to D range.
3. Depress the brake pedal firmly with the left foot, and gradually depress the accelerator pedal with
the right foot.
4. Read and note the engine speed as soon as it becomes constant; then release the accelerator pedal.
Caution
Steps 3 to 4 must be done within 5 seconds.
5. Shift the selector to N range and let the engine idle for one minute or more.
Note The idling cools the ATF and prevents oil degeneration.
6. Perform stall tests for the following ranges in the same manner.
(1) 2 range
(2) 1 range
(3) R range
Standard stall speed:
FE engine 2050—2150 rpm
F6 engine 1800—2050 rpm
Caution
Always provide adequate cooling time between individual range stall tests.
7C-15

7C TROUBLESHOOTING
Evaluation
Condition Possible cause
Worn oil pump
In all ranges Insufficient line
pressure
Oil leakage from oil pump, control
valve, and/or transaxle case
Stuck pressure regulator valve
In D, 2, and 1 Rear clutch slipping
Above specification In D range only One-way clutch slipping
In 2 range only Brake band slipping
Low and reverse brake slipping
Brake band slipping
In R range only Road test to determine if cause is low and reverse brake or reverse clutch:
a) Engine braking in 1 range Front clutch b) No engine braking in 1 range .... Low and reverse brake
Within specification All shift control elements within transaxle functioning normally
Below specification Engine out of tune Below specification
One-way clutch slipping within torque converter
76G07C-026
7C—16

TROUBLESHOOTING 7C
STEP 3 (TIME LAG TEST)
When the selector lever is shifted while the engine is idling, there is a certain time lapse, or time lag,
before shock is felt. This time lag test checks the condition of the front, rear, and one-way clutch, low
and reverse brake, and orifice check valve.
Preparation
Follow the test preparation procedure shown in STEP 2 (STALL TEST).
Procedure
1. Start the engine and verify that the idle speed is 950tso rpm.
2. Shift from N range to D range
3. Measure the time it takes from shifting until shock is felt with a stop watch.
4. Shift the selector to N range and run the engine at idle for one minute or more.
5. Perform the test for N range to R range in the same manner.
Note
Make three measurements for each test and take the average value.
Specified time lag: N D range 0.5—1.0 second
N R range 0.5—1.0 second
Evaluation
Condition Possible Cause
N -» D shift More than specification
Insufficient line pressure
N -» D shift More than specification Rear clutch slipping N -» D shift More than specification
One-way clutch slipping N -» D shift
Less than specification N-D accumulator not operating properly
N-R shift
More than specification
Insufficient line pressure
N-R shift
More than specification Low and reverse brake slipping
N-R shift
More than specification
Front clutch slipping N-R shift
Less than specification Stuck orifice check valve
N-R shift
Less than specification Excessive line pressure
76G07C-027
7C-17

7C TROUBLESHOOTING
STEP 4 (ROAD TEST)
This step is performed to check for problems in the various ranges. If these tests show any problems,
adjust or replace by referring to the QUICK DIAGNOSIS CHART and mechanical sections.
Caution
Perform the test at normal ATF operating temperature (50—80°C, 122—176°F).
Gearshift Function Check Items
1. Shift shock must be minimal, and shifting must be smooth.
2. Engine speed must not run away, and the shifting must not be delayed.
3. Transaxle must shift through Di D2 -»• D3 in D range.
4. Transaxle must shift from 3rd in D range to 2nd gear when 2 range is selected.
5. Transaxle must shift from 2nd to 1st when 1 range is selected from 3rd gear in D range.
6. Transaxle must not upshift in 1 range.
7. Transaxle must remain in 2nd gear in 2 range.
8. Transaxle must positively lock in P range.
The transaxle must positively lock when P range is selected while moving at a speed below 4 km/h
(2.5 mph) on level ground. The transaxle must positively lock when set in P range with the vehicle
on a gentle slope and the brakes disengaged.
Shift Speed
Throttle condition
(manifold vacuum) Hange Shift Vehicle speed km/h (mph) Throttle condition
(manifold vacuum) Hange Shift FE engine F6 engine
Fully opened 0—100 mmHg (0-3.94 inHg)
D
1st - 2nd 47—57 (29—35) 44-54 (27-33)
Fully opened 0—100 mmHg (0-3.94 inHg)
D 2nd - 3rd 106-119 (66—74) 95-108 (59-67) Fully opened 0—100 mmHg (0-3.94 inHg)
D 3rd - 2nd 95-103 (59-64) 86-94 (53-58)
Fully opened 0—100 mmHg (0-3.94 inHg)
D
2nd - 1st 35-39 (22-24) 34-38 (21-24)
Half-throttle 130 mmHg (5.12 inHg) D 1st - 2nd 18-31 (11-19) 18-31 (11-19) Half-throttle 130 mmHg (5.12 inHg) D 2nd -»• 3rd 39-68 (24—42) 44-73 (27-45)
Fully closed D 2nd - 1st 10-15 (6-9) 10-15 (6-9) Fully closed 1 2nd - 1st 32—39 (20-24) 33-40 (20-25)
1. Full-throttle: The throttle opening during kick-down when the manifold vacuum is between 0—100
mmHg (0—3.94 inHg)
2. Half-throttle: The throttle opening at manifold vacuum of 130 mmHg (5.12 inHg) 76G07C-028
7C-18

TROUBLESHOOTING 7C
Basic Gearshift Pattern
FE engine
mm Hg
(in Hg)
0 (0)
CO
40 (1.6)
100
(3.9)
200
(7.9) E 3 3 O CO
V 300 o (11.8)
400-(15.7)
Di«fD2 Di-fhD2
Di<-D2 I I
D1-D2
20 (12)
. Kick-down i D2^-p3 Daf-Da range
100 (62) 120 (74)
Vehicle speed km/h (mph)
F6 engine
mm Hg
(in Hg)
0
(0)
40 (1.6)
100 (3.9)
CD 3 c/> CO d>
E 3 3 o CD >
o H— "c co
200 (7.9)
300 (11.8)
400 (15.7)
Dl<-D2
DI^DZ DIT*DZ Kick-down Da 4
Da
Dzj+Da range
40 (25) 60 (37) 80 (50) 100 (62) 120 (74)
Vehicle speed km/h (mph)
76G07C-029
7C—19

7C TROUBLESHOOTING
STEP 5 (OIL PRESSURE TEST)
This step determines line pressure, and governor pressure to check the hydraulic components and
for oil leakage.
Line Pressure Test
Preparation
1. Connect the SST to the line pressure output point.
2. Connect a tachometer to the engine.
3. Follow the test preparation procedure show in STEP 2 (STALL TEST).
Procedure
76G07C-030
1. Start the engine and verify that the idle speed is 950-5° rpm.
2. Shift the selector lever to D range.
3. Read the line pressure at idle.
4. Depress the brake pedal firmly with the left foot, and gradually depress the accelerator pedal with
the right foot.
5. Read the line pressure as soon as the engine speed becomes constant; then release the accelera-
tor pedal.
Caution
Steps 4 to 5 must be done within 5 seconds.
5. Shift the selector lever to N range and let the engine idle for one minute or more.
6. Read the line pressure at idle and engine stall speeds for each range in the same manner.
7C—20

TROUBLESHOOTING 7C
Specified line pressure:
Range Pressure kPa (kg/cm2, psi) Range
Idle Stall
D 294-392 (3-4, 43-57) 883-1079 (9—11, 128-156)
2 785—1177 (8—12, 114—171) 785-1177 (8—12, 114-171)
1 294-392 (3-4, 43—57) 883-1079 (9—11, 128—156)
R 392-687 (4-7, 57-100) 1570—1864 (16—19, 228-270)
76G07C-031
Evaluation
Condition Possible cause
Below standard
In all ranges
Worn oil pump
Below standard
In all ranges Fluid leakage from the oil pump, control valve, or transaxle case
Below standard
In all ranges
Stuck pressure regulator valve Below standard
In D, 1, 2 ranges Fluid leakage from the rear clutch or governor hydraulic circuit, or both
Below standard
In R range only Fluid leakage from the low and reverse brake hydraulic circuit
Excessive line pressure at idle Leaking or disconnected vacuum hose Excessive line pressure at idle
Leaking vacuum diaphragm
76G07C-032
76G07C-033
Vacuum
gauge Line
pressure
Governor pressure
At Atmosphere Radical line Read
& 200 mmHg pressure governor
(7.87 inHg) reduction
Line Pressure Cutback Point
1. Connect the SST to the line pressure output point
and the governor pressure output point in the trans-
axle case, and place the gauges inside the vehicle.
2. Disconnect the hose to the vacuum diaphragm,
and plug it.
3. Connect a vacuum pump to the vacuum di-
aphragm, and place the pump inside the vehicle.
4. Gradually accelerate the vehicle in D range.
5. Read the governor pressure at the point where the
line pressure suddenly drops.
6. Apply 200 mmHg (7.87 inHg) vacuum, and re-
peat steps 4 and 5.
Standard
Vacuum mmHg (InHg) Governor pressure kPa (kg/cm2, psi)
Atmospheric pressure 98-157 (1.0—1.6, 14-23)
200 (7.87) 39-98 (0.4-1.0, 6—14)
Evaluation
Incorrect pressures
1. Missing diaphragm rod or rod length incorrect, or
both.
2. Stuck valve in control valve.
76G07C-034
7C—21

7C TROUBLESHOOTING
Governor Pressure Test
Preparation
1. Connect the SST to the governor pressure output point.
2. Place the SST inside the vehicle.
3. Warm up the ATF and check the ATF level.
Procedure
49 0378 400A
76G07C-035
1. Drive the vehicle in D range.
2. Read the governor pressure at the speeds listed in the table below.
Specified governor pressure:
Vehicle Speed km/h (mph) Governor Pressure kPa (kg/cm2, psi)
30 (19) 78-137 (0.8-1.4, 11-20)
55 (34) 157-226 (1.6-2.3, 23-33)
85 (53) 314-402 (3.2-4.1, 46-58)
Evaluation
Condition Possible Cause
Not within specification
Fluid leakage from the line pressure hydraulic circuit
Not within specification Fluid leakage from the governor pressure hydraulic circuit Not within specification
Defective or stuck governor valve
7C-22