ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-31
Engine Diagnosis Table
Perform troubleshooting referring to following table when ECM (PCM) has detected no DTC and no abnormality
has been found in visual inspection and engine basic inspection previously.
Condition Possible Cause Correction
Hard starting
(Engine cranks OK)Faulty idle air control system “DIAG. FLOW TABLE B-4” in this
section.
Faulty ECT sensor or MAF sensor ECT sensor or MAF sensor in Sec-
tion 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Low compression Compression check in Section
6A2.
Faulty hydraulic valve lash adjuster Valve lash adjuster in Section 6A2.
Compression leak from valve seat Valves inspection in Section 6A2.
Sticky valve stem Valves inspection in Section 6A2.
Weak or damaged valve springs Valves spring inspection in Section
6A2.
Compression leak at cylinder head gasket Cylinder head inspection in Section
6A2.
Sticking or damaged piston ring Piston ring inspection in Section
6A2.
Worn piston, ring or cylinder Cylinders, pistons and piston rings
inspection in Section 6A2.
Malfunctioning PCV valve PCV system inspection in Section
6E2.
Engine has no power
Engine overheating Refer to “OVERHEATING” in this
table.
Defective spark plug Spark plugs in Section 6F2.
Faulty ignition coil with ignitor Ignition coil in Section 6F2.
Fuel pressure out of specification
(dirty fuel filter, dirty or clogged fuel hose or
pipe, malfunctioning fuel pressure regulator,
malfunctioning fuel pump)“DIAG. FLOW TABLE B-3” in this
section.
Maladjusted TP sensor installation angle TP sensor in Section 6E2.
Faulty EGR system “DTC P0400 DIAG. FLOW TABLE”
in this section.
Faulty injector Fuel injector in Section 6E2.
Faulty TP sensor, ECT sensor or MAF sensor TP sensor, ECT sensor or MAF
sensor in Section 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Low compression Refer to the same item in “HARD
STARTING” of this table.
Dragging brakes Diagnosis in Section 5.
Slipping clutch Diagnosis in Section 7C1.
ENGINE GENERAL INFORMATION AND DIAGNOSIS (H27 ENGINE) 6-1-33
Surges
(Engine power varia-
tion under steady
throttle or cruise.
Feels like the vehicle
speeds up and down
with no change in the
accelerator pedal.)Defective spark plug
(excess carbon deposits, improper gap, and
burned electrodes, etc.)Spark plugs in Section 6F2.
Variable fuel pressure
(clogged fuel filter, kinky or damaged fuel hose
and line, faulty fuel pressure regulator)“DIAG. FLOW TABLE B-3” in this
section.
Faulty EGR system “DTC P0400 DIAG. FLOW TABLE”
in this section.
Faulty MAF sensor MAF sensor in Section 6E2.
Faulty injector Fuel injector in Section 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Excessive detonation
(The engine makes
sharp metallic knocks
that change with throt-
tle opening. Sounds
like pop corn pop-
ping.)Engine overheating Refer to “OVERHEATING” in this
table.
Faulty spark plug Spark plugs in Section 6F2.
Improper ignition timing Ignition timing in Section 6F2.
Clogged fuel filter and fuel lines Fuel pressure check in Section
6E2.
Faulty EGR system “DTC P0400 DIAG. FLOW TABLE”
in this section.
Faulty ECT sensor or MAF sensor ECT sensor or MAF sensor in Sec-
tion 6E2.
Faulty injector Fuel injector in Section 6E2.
Faulty ECM (PCM) Inspection of ECM (PCM) and its
circuit in this section.
Excessive carbon deposits in combustion
chamberPiston and cylinder head cleaning
in Section 6A2.
Poor knock sensor performance “DTC P0325 DIAG. FLOW TABLE”
in this section.
Overheating
Inoperative thermostat Thermostat in Section 6B.
Poor water pump performance Water pump in Section 6B.
Clogged or leaky radiator Radiator in Section 6B.
Improper engine oil grade Engine oil and oil filter change in
Section 0B.
Clogged oil filter or oil strainer Oil pressure check in Section 6A2.
Poor oil pump performance Oil pressure check in Section 6A2.
Dragging brakes Diagnosis in Section 5.
Slipping clutch Diagnosis in Section 7C1.
Blown cylinder head gasket Cylinder head inspection in Section
6A2. Condition Possible Cause Correction
6A2-6 ENGINE MECHANICAL (H27 ENGINE)
INSTALLATION
1) Install new intake manifold gaskets (1) to cylinder heads.
2) Install intake manifold (1).
Tighten bolts and nuts to specified torque.
Tightening torque
Intake manifold bolt and nut (a) :
23 N·m (2.3 kg-m, 16.5 lb-ft)
3) Install throttle body (2) to intake collector (1) with new throttle
body gasket.
Tighten bolts and nuts to specified torque.
Tightening torque
Throttle body bolt and nut (b) :
23 N·m (2.3 kg-m, 16.5 lb-ft)
4) Install EGR valve (1), EVAP canister purge valve (2), mani-
fold absolute pressure (MAP) sensor and each hoses to
intake collector and throttle body if removed.
Use new gasket, when installing IAC valve and EGR valve.
5) Install throttle body and intake collector assembly to intake
manifold with new intake collector gaskets.
1
(a)
(a)(a)
(a)
2 1
(b)
(b)
3. EVAP canister purge valve hose
2
1
3
6A2-10 ENGINE MECHANICAL (H27 ENGINE)
4) Disconnect EGR pipe from right (No.2) bank exhaust mani-
fold if right side exhaust manifold is removed.
5) Remove oil level gauge guide (3) if left side exhaust manifold
is removed.
6) Detach P/S pump assembly as following, if left side exhaust
manifold is removed.
a) Loosen P/S pump drive belt by loosening tensioner bolt.
b) Remove P/S pump mounting bolts.
c) Detach P/S pump assembly (4) with its hoses from cylinder
block.
7) Remove exhaust manifold covers (2) from exhaust manifolds
(1).
8) Hoist vehicle.
9) For 4WD vehicle, before disconnecting front propeller shaft,
put match mark (1) on joint flange and propeller shaft to facil-
itate their installation as shown in the figure.
10) For 4WD vehicle, disconnect propeller shaft from front differ-
ential.
11) Remove exhaust manifold stiffeners (1).
12) Remove stabilizer bar mounting bolt and pull down stabilizer
bar if right side exhaust manifold is removed.
13) Remove exhaust manifolds and their gaskets from cylinder
heads.
1
4
32
2. Exhaust No.1 pipe
A. Without WU-TWC
B. With WU-TWC
ENGINE MECHANICAL (H27 ENGINE) 6A2-11
INSTALLATION
1) Install new manifold gaskets to cylinder heads and No.1 pipe
gasket to exhaust No.1 pipe.
2) Install exhaust manifolds.
•Always install new bolts with pre-coated adhesive to the
locations with ✱ mark.
•Tighten both manifold nuts and bolts to specified torque.
Tightening torque
Exhaust manifold bolt and nut (a) :
30 N·m (3.0 kg-m, 21.5 lb-ft)
3) Install stabilizer bar if it was removed. Refer to “STABILIZER
BAR / BUSHINGS” in Section 3D.
4) Install exhaust manifold stiffeners (if removed).
5) Install exhaust No.1 pipe (1).
Tighten exhaust No.1 pipe bolts to specified torque.
Tightening torque
Exhaust No.1 pipe bolt (b) :
50 N·m (5.0 kg-m, 36.5 lb-ft)
6) Tighten exhaust No.1 pipe nuts to specified torque.
Tightening torque
Exhaust No.1 pipe nut (b) :
50 N·m (5.0 kg-m, 36-5 lb-ft)
1. Left (No.1) exhaust manifold
2. Right (No.2) exhaust manifold
2. Exhaust No. 2 pipe
1. Exhaust No.1 pipe
2. Exhaust manifold
A. Without WU-TWC
B. With WU-TWC
ENGINE MECHANICAL (H27 ENGINE) 6A2-17
Valves and Cylinder Heads
1. Cylinder block 6. Exhaust valve 11. Valve stem oil seal 16. Cylinder head bolt
(hex hole bolt)
2. RH bank cylinder head 7. Intake valve 12. Valve spring retainer Tightening Torque
3. LH bank cylinder head 8. Valve spring seat 13. Valve cotter Do not reuse
4. RH bank cylinder head gasket :
Carved lot number on cylinder head
gasket should face up (toward cylinder
head side).9. Outer valve spring :
Be sure to position spring in place with
its bottom end (small-pitch end) facing
the bottom (valve spring seat side).14. Valve guide Apply engine oil to
sliding surface of
each parts.
5. LH bank cylinder head gasket :
Carved lot number on cylinder head
gasket should face up (toward cylinder
head side).10. Inner valve spring :
Be sure to position spring in place with
its bottom end (small-pitch end) facing
the bottom (valve spring seat side).15. Cylinder head bolt
6A2-18 ENGINE MECHANICAL (H27 ENGINE)
INSPECTION
Valve guides
Using a micrometer and bore gauge, take diameter readings on
valve stems and guides to check stem-to-guide clearance. Be
sure to take reading at more than one place along the length of
each stem and guide.
If clearance exceeds limit, replace valve and valve guide.
Valve stem-to-guide clearance :
INSTALLATION
1) Clean mating surface on cylinder head and cylinder block.
Remove oil, old gasket and dust from mating surface.
2) Install knock pin (4) to cylinder block.
3) Apply sealant “A” to cylinder head gasket (1) as shown in the
figure.
“A” : Sealant 99000-31150
Sealant amount (Width “w”) :
4 mm (0.158 in.)
4) Install new cylinder head gasket (1) to cylinder block as
shown in the figure. carved lot number (5) on cylinder head
gasket (1) should face up (toward cylinder head side).Standard Limit
Valve stem
diameterIntake 5.965 – 5.980 mm
(0.2348 – 0.2354 in.)–
Exhaust 5.940 – 5.955 mm
(0.2339 – 0.2344 in.)–
Valve guide
I.D.In & Ex 5.985 – 6.010 mm
(0.2356 – 0.2366 in.)–
Stem-to-guide
clearanceIntake 0.035 – 0.045 mm)
(0.0014 – 0.0018 in.)0.07 mm
(0.0027 in.)
Exhaust 0.060 – 0.070 mm
(0.0024 – 0.0028 in.)0.09 mm
(0.0035 in.)
[A] : RH ( No.2) bank
[B] : LH (No.1) bank
2. Crankshaft pulley side
3. Flywheel side
6E2-20 ENGINE AND EMISSION CONTROL SYSTEM (SEQUENTIAL MULTIPORT FUEL INJECTION FOR H27 ENGINE)
CLEANING
Clean throttle body bore and bypass air passages (1) by blowing
compressed air.
INSTALLATION
1) Clean mating surfaces and install throttle body gasket to
intake collector (1) with new gasket (2).
2) Install throttle body to intake collector and tighten bolts.
3) Connect PCV hose.
4) Install throttle body and intake collector to intake manifold
with new intake collector gaskets.
5) Install EGR pipe with new gaskets.
6) Connect breather hose and EVAP canister purge valve hose
and install PCV valve to cylinder head.
7) Connect connectors of EVAP canister purge valve, MAP
sensor and EGR valve.
Fix wire harness with clamps.
8) Install clamp bracket to intake collector.
9) Connect ground wire connector.
10) Connect connectors of TP sensor, ground and IAC valve.
11) Install surge tank pipe to intake manifold with new gaskets
and intake air pipe to throttle body. Install surge tank cover.
12) Connect engine coolant hoses to throttle body.
13) Connect accelerator cable and A/T throttle cable (A/T).CAUTION:
Do not blow compressed air through bypass air pas-
sage with IAC valve installed to throttle body. This will
cause IAC valve to malfunction.
TP sensor, idle air control valve or other components
containing rubber must not be places in a solvent or
cleaner bath.
A chemical reaction will cause these parts to swell,
harden or get distorted.