1987 MAZDA 626 engine

7B TROUBLESHOOTING (G4A-EL)
Procedure
86U07B-034
1. Block the wheels and apply the parking brake.
2. Connect a tachometer to the engine.
3. Shift the selector lever to R.
4. Firmly depress the foot brake with the left foot, and gently depress the accelerator pedal with the right.
5. When the engine speed no longer increases, quickly read the engine speed and release the ac-
celerator.
Caution
Steps 4 ->• 5 must be done within 5 seconds.
6. Move the selector lever to N and let the engine idle for at least one minute.
Caution
The reason for idling for at least one minute is to cool the ATF and to prevent deterioration
of the fluid.
7B-28

TROUBLESHOOTING (G4A-EL) 7B
7. Perform the stall test for the following ranges in the same manner.
(1) D range (4) L range
(2) D range (Hold) (5) L range (Hold)
(3) S range (Hold)
Caution
Be sure to allow sufficient cooling time between each stall test.
Engine stall speed: D.S.L range 2170—2270 rpm
R range 2130—2230 rpm
Note
The stall test can be performed with the EC-AT Tester in place of a tachometer.
Drum stall speed indication: 0 rpm
76G0/B-029
Evaluation
Condition Possible cause
Above specification
In all ranges Insufficient line
pressure
Worn oil pump
Above specification
In all ranges Insufficient line
pressure Oil leakage from oil pump, control valve, and/or transmission case
Stuck pressure regulator valve
Above specification
In forward ranges Forward clutch slipping One-way clutch 1 slipping
Above specification
In D range One-way clutch 2 slipping
Above specification
In S (Hold) and L (Hold) ranges Coasting clutch slipping
Above specification In D (Hold) and S (Hold) ranges 2-4 brake band slipping Above specification
In R, L and L (Hold) ranges Low and reverse brake slipping
Above specification
In R range
Low and reverse brake slipping Reverse cluch slipping Perform road test to determine whether problem is low and reverse brake or reverse clutch
a) Engine brake applied in 1st ...Reverse clutch
b) Engine brake not applied in 1st ...Low and reverse brake
Within specification All shift control elements within transmission are func-
tioning normally.
Below specification
Engine out of tune
Below specification One-way clutch slipping within torque converter
86U07B-036
7B-29

7B TROUBLESHOOTING (G4A-EL)
STEP 5 (TIME LAG TEST)
If the selector lever is shifted while the engine is idling, there will be a certain time lapse, or time lag,
before shock is felt. This step checks this time lag for checking condition of the 1-2, N-R, and N-D
accumulators, forward, and one-way clutches, 2-4 brake band, and low and reverse brake.
Preparation
76G07B-030
Procedure
1. Start the engine and check the idle speed in P range.
Idle speed: 900 ±58 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 speed for at least one minute.
5. Perform the test for the following shifts in the same manner.
(1) N D range (Hold mode)
(2) N -» R range
Note
Make three measurements for each test and take the average value.
Specified time lag: N -> D range
N -»• R range
Evaluation
Condition Possible Cause
N D (Economy) shifting
More than specification
Insufficient line pressure Forward clutch slipping One-way clutch 1 slipping One-way clutch 2 slipping N D (Economy) shifting
Less than specification N-D accumulator not operating properly
Excessive line pressure
N-D (Hold) shifting
More than specification
Insufficient line pressure Forward clutch slipping 2-4 brake band slipping One-way clutch 1 slipping N-D (Hold) shifting
Less than specification 1-2 accumulator not operating properly
Excessive line pressure
N R shifting
More than specification
Insufficient line pressure Low and reverse brake slipping Revese clutch slipping N R shifting
Less than specification N-R accumulator not operating properly
Excessive line pressure
86U07B-038
0.5—1.0 second
0.5—1.0 second
7B-30

TROUBLESHOOTING (G4A-EL) 7B
STEP 6 (OIL PRESSURE TEST)
This step checks line pressures for checking the hydraulic components and for oil leakage.
Line Pressure Test
Preparation
1. Perform the preparation procedure shown in STEP 4 (STALL TEST).
2. Connect a tachometer to the engine.
3. Connect the SST to the line pressure inspection hole (square head plug L)
Procedure
76G07B-031
1. Start the engine and check the idle speed in P range
Idle speed: 900 -so rpm
2. Shift the selector lever to D range and read the line pressure at idle.
3. Depress the brake pedal firmly with the left foot and gradually depress the accelerator pedal with
the right foot.
4. Read the line pressure as soon as the engine speed becomes constant, then release the accelera-
tor pedal.
Caution
Steps 3 to 4 must be performed within 5 seconds.
5. Shift the selector lever to N range and run the engine at idle for at least one minute.
6. Read the line pressure at idle and engine stall speeds for each range in the same manner.
7B—31

TROUBLESHOOTING (G4A-EL) 7B
Throttle Pressure Test
This step checks line pressure for checking the hydraulic components and for improper adjustment
of throttle cable.
Preparation
1. Perform the preparation procedure shown in STEP 4 (STALL TEST).
2. Connect a tachometer to the engine.
3. Connect the SST to the throttle pressure inspection hole (square head plug T).
Procedure
76G07B-034
1. Start the engine and check the idle speed in P range.
Idle speed: 900 _5o rpm
2. Shift the selector lever to D range and read the throttle pressure at idle.
3. Depress the brake pedal firmly with the left foot and gradually depress the accelerator pedal with
the right foot.
4. Read the throttle pressure as soon as the engine speed becomes constant, then release the ac-
celerator pedal.
Caution
Steps 3 to 4 must be performed within 5 seconds.
Specified throttle pressure:
Throttle pressure kPa (kg/cm2, psi)
When idling 39-88 (0.4—0.9, 6—13)
At stall speed 471—589 (4.8—6.0, 68—85)
Evaluation
Throttle pressure Possible location of problem
Not within specification
Throttle valve sticking Pressure regulator valve sticking Improper adjustment of throttle cable
7B—33

7B TROUBLESHOOTING (G4A-EL)
STEP 7 (ROAD TEST)
This step is performed to inspect for problems at the various ranges. If these tests show any problems,
adjust or replace by referring to the electronic system component or mechanical sections.
Caution
Perform the test at normal ATF operating temperature (50—80°C, 122—176°F).
D Range Test
Shift point, shift pattern, and shift shock
1. Shift the selector lever to D range and select the Power mode.
2. Accelerate the vehicle with half and full throttle valve opening.
Note
Throttle sensor voltage of the EC-AT Tester represents the throttle valve opening.
3. Check that 1-2, 2-3 and 3-OD up-shifts and downshifts and lock-up are obtained. The shift points
must be as shown in the D range (Power) shift diagram.
Note
a) Drum speed (rpm) of the EC-AT Tester represents the shift point.
b) Vehicle speed of the EC-AT Tester and speedometer and vehicle speed on a chassis
roller may not meet the specified shift pattern because of tire size. Therefore, check
the shift points with the Drum speed.
c) There is no lock-up when the coolant temperature is below 72°C (162°F).
d) There is no overdrive when the cruise control is operating and there is a 3 km/h (1.9
mph) difference between the pre-set cruise speed and vehicle speed, or set or resume
switch is ON.
e) There is no lock-up when the brake pedal is depressed.
4. Check the up-shifts for shift shock or slippage in the same manner.
5. While driving in OD, shift the selector lever to S range and check that 4-3 downshift immediately
occurs, then decelerate and check that engine braking effect is felt in only 3rd gear.
7B—34

7B TROUBLESHOOTING (G4A-EL)
Evaluation
Condition Possible Cause
No 1-2 up- or down-shift Stuck 1-2 shift solenoid valve
Stuck
1
-2 shift valve
No 2-3 up- or down-shift Stuck 2-3 shift solenoid valve Stuck 2-3 shift valve
No 3-OD up- or down-shift Stuck 3-4 shift solenoid valve Stuck 3-4 shift valve
No lock-up shift Stuck lock-up control solenoid valve Stuck lock-up control valve
Incorrect shift point Mis-adjusted throttle sensor Sticking shift valves
Excessive shift shock or slippage
Excessive shift shock Stuck accumulators Stuck or no one-way check orifice
Worn clutches, brakes, or one-way clutch
No engine braking effect Worn clutches or brakes
76G07B-035
Noise and vibration
Drive the vehicle in OD (lock-up), OD (no lock-up), 3rd (Hold) and check for abnormal noise or vibration.
Note
Abnormal noise and vibration can also be caused by the torque converter, drive shaft, or
differential. Therefore, checking of cause must be made with extreme care.
Kick-down
Drive the vehicle in OD, 3rd and 2nd gears and check that kick-down occurs for OD->3, OD->2, OD->1,
3->2, 3-+1, 2-> 1, and the shift points are as shown in the shift diagram.
S Range Test
Shift pattern
1. Shift the selector lever to S range and select the Economy mode.
2. Accelerate the vehicle and check that 1-2 and 2-3 up-shifts and down-shifts are obtained, and that
no overdrive and no lock-up are obtained.
Note
a) Inspections of shift shock and shift point are not necessary because these are the same
as those of the D Range Test.
b)ln S range, the shift patterns for Economy and Power modes are the same.
c) Shift points are the same as those of the D range (Power) shift diagram.
3. While driving in S range (Economy mode) and 3rd gear, select the Hold mode and check that 3rd
gear is held until the 3-2 down-shift point as shown in the S range (Hold) shift diagram is achieved.
4. Accelerate the vehicle with S range (Hold mode) and check that 2nd gear is held.
7B i—36

TROUBLESHOOTING (G4A-EL) 7B
76G07B-036
Noise and vibration
Drive the vehicle in 2nd gear (Hold mode) and check for abnormal noise or vibration.
Note
Abnormal noise and vibration can also be caused by the torque converter, drive shaft or
differential. Therefore, checking of cause must be made with extreme care.
L Range Test
Shift pattern
1. Shift the selector lever to L range and select the mode.
2. Accelerate the vehicle and check that the 1-2 up- and down-shiftings are obtained and that no 3rd
gear, no OD, and no lock-up are obtained.
Note
Inspection of shift shock and shift point are not necessary because these are the same
as those of the D Range Test.
3. Drive in 1st gear then decelerate and check that engine braking effect is felt.
Note
a) In L range, the shift patterns for Economy and Power modes are the same.
b) Shift points are the same as those of the D range (Power) shift diagram.
4. While driving in S range (Hold mode) and 2nd gear, shift the selector lever to L range and check
that 2nd gear is held until the 2-1 down-shift point as shown in the L range (Hold) shift diagram
is achieved.
5. Accelerate the vehicle in L range (Hold mode) and check that 1st gear is held.
7B—37