1987 MAZDA 626 engine

1B TUNE-UP PROCEDURE 1 B
86U01X-008
Coolant Level (Cold engine)
1. Check that the coolant level is near the radiator inlet
port.
2. Check that the level in the coolant reservoir is be-
tween the FULL and LOW marks.
Add coolant if necessary.
Warning
a) Never remove the radiator cap while the en-
gine is hot.
b) Wrap a thick cloth around the cap and care-
fully remove it.
Drive Belt
1. Check that the drive belt is positioned in the pul-
ley groove.
2. Check the drive belt for wear, cracks, or fraying.
Replace if necessary.
3. Check the drive belt tension by using the tension
gauge.
Standard belt tension N (kg, lb)
76G01B-006

Belt New Used
Alternator 589-785 (60-80, 132-176) 491-687 (50-70, 110-154)
P/S 687-883 (70-90,154-198) 589-785 (60-80.132-176)
A/C 687-883 (70-90,154-198) 589-785 (60-80,132-176)

76G01B-007
Adjusting bolt
76G01B-008
4. Check the drive belt deflection by applying moder-
ate pressure (98 N, 10 kg, 22 lb) midway between
the pulleys.
(1) Alternator belt deflection
New : 6—8 mm (0.24—0.31 in)
Used: 7—9 mm (0.27—0.35 in)
If necessary, loosen the alternator mounting
bolts and adjust the belt deflection by turning
the adjusting bolt.
Tightening torque
®: 31—46 Nm (3.2—4.7 m-kg, 23—34 ft-lb)
(§): 37—52 Nm (3.8—5.3 m-kg, 27—38 ft-lb)
(2) P/S belt deflection
New : 8—10 mm (0.31—0.39 in)
Used: 9—11 mm (0.35—0.43 in)
If necessary, loosen the idler pulley lock bolt
and adjust the belt deflection by turning the ad-
justing bolt.
Tightening torque of lock bolt:
37—52 N-m (3.8—5.3 m-kg, 27—38 ft-lb)
1B—6

TUNE-UP PROCEDURE 1 B
High-Tension Lead
Check the following points. Clean or replace if
necessary.
1. Damaged lead
2. Carbon deposits
86U01X-014
i^rrr ' /
49 0187 280
76G01B-011
76G01B-012
Hydraulic Lash Adjuster (HLA)
Note
Tappet noise may occur if the engine is not
operated for an extended period of time. The
noise should stop after the engine has
reached normal operating temperature.
1. Check for tappet noise. If noise exists, check the
following points.
(1) Engine oil condition and level
(2) Engine oil pressure (Refer to Section 2A)
2. If the noise does not stop, check for movement of
each HLA by pushing it during disassembly.
3. If the HLA moves, replace the HLA. (Refer to page
1B—60.)
Ignition Timing
1. Warm up the engine and run it at idle.
2. Turn all electric loads OFF.
3. Connect a timing light tester.
4. Disconnect the vacuum hose from the vacuum
control, and plug the hose.
5. Check that the ignition timing mark (yellow) on the
crankshaft pulley and the timing mark on the tim-
ing belt cover are aligned.
Ignition timing: 12° ± 1° BTDC
(at idle speed)

76G01B-008

1B—8

TUNE-UP PROCEDURE 1 B
76G01B-015
6. If necessary, adjust the ignition timing by turning
the distributor.
Idle Speed
1. Ground the test connector to the vehicle with a
jumper wire.
2. Connect a tachometer to the engine.
3. Check the idle speed.
Idle speed: 750 ± 50 rpm
4. If necessary, remove the blind cap from the throt-
tle body and adjust by turning the air adjust screw.
5. Install the blind cap and disconnect the jumper wire
from the test connector.
Idle Mixture
1. Connect an exhaust gas analyzer to the vehicle.
2. Measure the CO and HC concentration.
CO concentration: 1.5 ± 0.5%
HC concentration: Less than 1,000 ppm
3. If necessary, remove the blind cap from the air flow
meter and adjust by turning the bypass air adjust
screw with SST.
4. Install the blind cap to the air flow meter and dis-
connect the jumper wire from the test connector.
76G01B-016
1B—9

1 B ON-VEHICLE INSPECTION
76G01B-017
86U01X-020
76G01B-018
Possible Cause
ON-VEHICLE INSPECTION
If the engine exhibits low power, poor fuel economy,
or poor idle, check the following points.
1. Ignition system (Refer to Section 5)
2. Compression
3. Fuel system (Refer to Section 4C)
COMPRESSION
1. Check that the battery is fully charged. Recharge
if necessary.
2. Warm up the engine to the normal operating tem-
perature.
3. Turn it off for about 10 minutes to allow the exhaust
manifold to cool.
4. Remove all spark plugs.
5. Disconnect the primary wire connector from the
ignition coil.
6. Connect a compression gauge to No.1 spark plug
hole.
7. Fully depress the accelerator pedal and crank the
engine.
8. Note the maximum gauge reading.
9. Check each cylinder.
Standard compression:
1,422 kPa (14.5 kg/cm2, 206 psi)—290 rpm
Leaded fuel
1,373 kPa (14.0 kg/cm2,199 psi)—310 rpm
... Unleaded fuel
Compression limit:
996 kPa (10.2 kg/cm2, 144 psi)—290 rpm
Leaded fuel
961 kPa (9.8 kg/cm2, 139 psi)—310 rpm
... Unleaded fuel
If compression is low, pour heavy oil into the cylinder and turn the crankshaft several times Check compression once more
»
Is compression increased? Yes 1. Worn piston or piston rings
2. Worn cylinder wall
No
1. Worn piston or piston rings
2. Worn cylinder wall
No 1. Defective cylinder head gasket 2. Distorted cylinder head
Is compression in adjacent cylinder low? Yes
1. Defective cylinder head gasket 2. Distorted cylinder head
Is compression in adjacent cylinder low?
No 1. Improper valve seating
2. Valve sticking in guide
3. Defective cylinder head gasket
86U01X-022
1B—10

ON-VEHICLE MAINTENANCE (TIMING BELT) 1 B
ON-VEHICLE MAINTENANCE
TIMING BELT
Removal
1. Disconnect the negative battery cable.
2. Remove in the sequence shown in the figure referring to the removal note for specially marked parts.
76G01A-108
76G01B-020
1. Center cover
2. High-tension lead and spark plug
3. Engine side cover
4. Drive belt
5. Crankshaft pulley
6. Engine mount bracket
7. Upper timing belt cover
8. Lower timing belt cover
9. Baffle plate
10. Timing belt tensioner
11. Timing belt tensioner spring
12. Timing belt
1B—11

ON-VEHICLE MAINTENANCE (TIMING BELT) 1 B
10. Check the timing belt deflection. If the deflection
is not correct, repeat the adjustment from step 5
above.
Timing belt deflection: 7.5—8.5 mm
(0.30—0.33 in) /98 N (10 kg, 22 lb)
Caution
Be sure not to apply tension other than that
of the tensioner spring.
76G01B-027
Drive belt
Install each drive belt, and check the belt deflection.
(Refer to page 1B—6.)
76G01B-028
Spark plug
1. Apply anti-seize compound or molybdenum-based
lubricant to the spark plug threads.
2. Install the spark plugs.
Tightening torque:
15—23
N
m (1.5—2.3 m-kg, 11—17 ft-lb)
79G01C-021
Steps After Installation
Perform the necessary engine adjustment. (Refer to
TUNE-UP PROCEDURE.)
86U01X-029
1B—15

1 B ON-VEHICLE MAINTENANCE (CYLINDER HEAD)
CYLINDER HEAD
Removal
Warning: Release the fuel pressure. (Refer to Section 4C.)
1. Disconnect the negative battery cable.
2. Drain the engine coolant.
3. Remove in the sequence shown in the figure referring to the removal note for specially marked parts.
1B—16

76G01B-034

1 B ON-VEHICLE MAINTENANCE (CYLINDER HEAD)
1. Center cover
2. High-tension lead and spark plug
3. Accelerator cable
4. Air intake pipe assembly
5. Fuel hose
6. Upper radiator hose
7. Heater hose
8. Brake vacuum hose
9. Canister hose (Unleaded fuel)
10. Engine harness connector and ground
11. EGR pipe (Unleaded fuel)
12. A/C compressor and bracket
13. Exhaust manifold insulator
14. Exhaust pipe
15. Exhaust manifold
16. Intake manifold bracket
17. Intake manifold assembly
18. Distributor
19. Engine mount stay
20. Upper timing belt cover
21. Timing belt tensioner spring
22. Timing belt
23. Cylinder head cover
24. Cylinder head and gasket
76G01B-030
Removal note
Fuel hose
Warning
a) Cover the hose with a rag because fuel will
spray out when disconnecting.
b) Keep sparks and open flame away from the
fuel area.
Plug the disconnected hoses to avoid fuel leakage.
86U01X-032
Timing belt
1. Before removing the timing belt, turn the crankshaft
to align the mating marks of the camshaft pulleys
with the seal plate timing mark.
Note
For intake side camshaft pulley, align "I"
mark.
For exhaust side camshaft pulley, align "E"
mark.
76G01B-031
2. Loosen the timing belt tensioner lock bolt.
3. Shift the tensioner outward as far as possible, then
temporarily tighten it.

76G01B-034

1B—17