low oil pressure MITSUBISHI LANCER EVOLUTION IV 1998 Workshop Manual

ENGINE – Engine Adjustments11-5
2. AUTO TENSIONER CHECK
(1) Stop the engine from the idle speed and check that the
belt rests within the auto tensioner pulley width.
(2) Remove the drive belt.
(For the removal of the drive belt, refer to P.11-9.)
(3) Fit a spinner handle or similar tool into the tool mounting
hole of the auto tensioner and turn the tensioner clockwise
and counterclockwise to ensure that it does not bind.
(4) If step (1) or (3), or both, have been checked abnormally,
replace the auto tensioner.
(5) Reinstall the drive belt.
3. LASH ADJUSTER CHECK
NOTE
If an unusual knocking noise can be heard immediately after
the engine has started or while it is running and if that is
probably attributable to the lash adjuster, make the following
checks.
(1) Check the engine oil and add or change oil as necessary.
NOTE
(1) If the engine oil level is low, air is taken in through
the oil screen, entering the oil passage.
(2) If the oil level is too high, the cranks agitate oil causing
oil to trap a large amount of air.
(3) Air does not easily separate from a deteriorated oil
that can contain an increased amount of air.
When air trapped in oil for these reasons gets into the
high-pressure chamber of the lash adjuster, the air in
the high-pressure chamber is compressed to shrink the
lash adjuster excessively while the valve is opening,
resulting in an unusual noise occurring. This is the same
symptom developing when the valve clearance is adjusted
to an excessive value.
The problem in this case is gone when air is released
from the lash adjuster.
(2) Start the engine and carry out several cycles (10 or less)
of mild racing*.
If the noise is gone after racing, it indicates that air has
been released from the high-pressure chamber of the
lash adjuster, restoring the lash adjuster to normal
operating conditions.
*: Gradually (extending over a 30-sec. period) increase
the engine speed from idle speed to 3,000 r/min and
then reduce it down to the idle speed gradually
(extending over a 30-sec. period).
NOTE
(1) If the vehicle is parked on a slope for a long time,
the amount of oil in the lash adjuster will decrease,
causing air to get into the high-pressure chamber
when the engine is started.
(2) After the vehicle has been parked for a long time,
oil drains out of the oil passage and it takes a long
time for the oil to reach the lash adjuster. This can
cause air to get into the high-pressure chamber.
Tool mounting hole
Good
MAX
MIN
High-pressure
chamber

ENGINE – Engine Adjustments11-8
(5) Set compression gauge to one of the spark plug holes.
(6) Crank the engine with the throttle valve fully open and
measure the compression pressure.
Standard value
(at engine speed of 250 r/min): 11.5 kg/cm
2
Limit (at engine speed of 250 r/min): 9.7 kg/cm2
(7) Measure the compression pressure for all the cylinders,
and check that the pressure differences of the cylinders
are below the limit.
Limit: Max. 1.0 kg/cm
2
(8) If there is a cylinder with compression or a compression
difference that is outside the limit, pour a small amount
of engine oil through the spark plug hole, and repeat
the operations in steps (5) through (7).
a. If the compression increases after oil is added, the
cause of the malfunction is a worn or damaged piston
ring and/or cylinder inner surface.
b. If the compression does not rise after oil is added,
the cause is a burnt or defective valve seat, or pressure
is leaking from the gasket.
(9) Connect the crank angle sensor connector.
(10)Install the spark plugs.
(11) Install the ignition coil and connect the ignition coil
connector.
(12)Erase the diagnosis codes by keeping the battery minus
(–) cable disconnected for more than 10 seconds.
NOTE
This will erase the diagnosis code resulting from the crank
angle sensor connector being disconnected.
8. MANIFOLD VACUUM CHECK
(1) Before inspection, set the vehicle to the pre-inspection
condition.
(2) Connect a tachometer connector.
(3) Attach a three-way union to the vacuum hose between
the fuel pressure regulator valve and the intake manifold,
and connect a vacuum gauge.
(4) Start the engine and check that idle speed is within
standard value.
Standard value: 850 ± 50 r/min
5. Check the manifold vacuum at idling.
Limit: Min. 55 kPa {410 mmHg}
Compression gauge
Vacuum gauge
Fuel pressure
regulator valve

ENGINE – Cylinder Head Gasket11-20
(3) Tighten the bolts by the following procedure.
StepOperation
1Tighten to 78 Nm {8.0 kgf
m} in the order shown in the
illustration.
2Fully loosen in the reverse order of that shown in the
illustration.
3Tighten to 20 Nm {2.0 kgf
m} in the order shown in the
illustration.
4Mark the head of the cylinder head bolt and cylinder head
by paint, then tighten 90
of a turn in the order shown in
the illustration.
5Tighten 90
of a turn in the order shown in the illustration.
Check that the painted mark of the head bolt is lined up
with that of the cylinder head.
Caution
(1) Always make a tightening angle just 90
. If it is less
than 90
, the head bolt will be loosened.
(2) If it is more than 90
, remove the head bolt and repeat
the procedure from step 1.
COIL RETURN PIPE GASKET INSTALLATION
Install the gasket with the printed portion toward the oil pan.
DHIGH-PRESSURE FUEL HOSE INSTALLATION
(1) Apply a small amount of new engine oil to the O-ring,
then fit the O-ring in the delivery pipe.
Caution
Do not let any engine oil get into the delivery pipe.
(2) Check that the high pressure hose turns smoothly.
If the hose does not turn smoothly, the O-ring is probably
being clamped. Disconnect the high-pressure fuel hose
and check the O-ring for damage. After this, re-install
the hose to the delivery pipe and check that the hose
turns smoothly.
(3) Tighten the mounting bolts to the specification.
Intake sideMB991654
Exhaust sideFront of engine
Step 4
90

Painted markStep 5
90

Painted mark
GasketPrinted portion

ENGINE – Engine Assembly11-3 5
E ENGINE ASSEMBLY REMOVAL
After checking that all cables, hoses and harness connectors,
etc., are disconnected from the engine, lift the chain block
slowly to remove the engine assembly upward from the engine
compartment.
INSTALLATION SERVICE POINTS
 A ENGINE ASSEMBLY INSTALLATION
Install the engine assembly, checking that the cables, hoses,
and harness connectors are not clamped.
 B ENGINE MOUNT BRACKET INSTALLATION
(1) Place a garage jack against the engine oil pan with a piece of wood in between, and install the engine mount
bracket while adjusting the position of the engine.
(2) Support the engine with the garage jack.
(3) Remove the chain block and support the engine assembly
with the special tools.
 C HIGH-PRESSURE FUEL HOSE INSTALLATION
(1) Apply a small amount of new engine oil to the O-ring, then fit the O-ring in the delivery pipe.
Caution
Do not let any engine oil get into the delivery pipe.
(2) Check that the high pressure hose turns smoothly. If the hose does not turn smoothly, the O-ring is probably
being clamped. Disconnect the high-pressure fuel hose
and check the O-ring for damage. After this, re-install
the hose to the delivery pipe and check that the hose
turns smoothly.
(3) Tighten the mounting bolt to the specification.
MZ203826 or MZ203827
MB991453

MPI – General Information13-2
MULTIPOINT INJECTION (MPI)
GENERAL INFORMATION
OMPI System Diagram

1 Injector

2 ISC servo

3 Fuel pressure control valve

4 Waste gate solenoid valve

5 Secondary air control solenoid valve
Control relay
Fuel pump relay
A/C relay
Ignition coil
Exhaust temperature warning lamp
Engine warning lamp
Diagnosis output
Alternator G terminal
Fan motor relay
Tachometer
Fuel pump relay No.2 1 Oxygen sensor
2 Air flow sensor
3 Intake air temperature sensor
4 Throttle position sensor
5 Idle switch
6 Camshaft position sensor
7 Crank angle sensor
8 Barometric pressure sensor
9 High temperature sensor
10 Engine coolant temperature sensor
11 Detonation sensor
Power supply voltage
Ignition switch-IG
Ignition switch-ST
Vehicle speed sensor
A/C switch
Power steering fluid pressure switch
Alternator FR signalEngine ECU
1 Oxygen sensor
2 Air flow sensor3
Intake air tem-
perature sensor
4,
5
6 Camshaft position
sensor
7 Crank angle sensor 8 Barometric
pressure sensor
9 High temperature
sensor 10 Coolant temperature sensor
11 Detonation sensor
1 Injector
2 ISC servo

3 Fuel pressure
control valve

4 Waste gate
solenoid valve
5 Secondary air
control solenoid
valveCanister
Check valveFrom
fuel
tank
Throttle position
sensor (with a
built-in
idle
switch)
Secondary
air valve
AirTo fuel
tankFuel
pressure
regulatorFrom
fuel
pump
Waste gate
actuator
Catalytic converter
Given above is the MPI system diagram for EVOLUTION-IV. The MPI system for EVOLUTION-V is different
from this in the following point;
Oxygen sensor with a heater is adopted.
The diagnosis connector power supply circuit is different.
The high temperature sensor is no longer used.

MPI – Troubleshooting13-6
TROUBLESHOOTING
1. DIAGNOSIS FUNCTION
1-1 ENGINE WARNING LAMP (CHECK ENGINE LAMP)
If an abnormality occurs in any of the following items related
to the Multipoint Fuel Injection (MPI) system, the engine
warning lamp will illuminate.
If the lamp remains illuminated or if the lamp illuminates while
the engine is running, check the diagnosis code output.
Engine warning lamp inspection items
Engine-ECU
Air flow sensor (AFS)
Intake air temperature sensor
Throttle position sensor (TPS)
Engine coolant temperature sensor
Crank angle sensor
Camshaft position sensor
Barometric pressure sensor
Detonation sensor
Injector
Ignition coil, power transister
Misfire <Evolution-V only>
1-2 METHOD OF READING AND ERASING DIAGNOSIS
CODES
(1) Use the special tool to earth No.1 terminal (diagnosis
control terminal) of the diagnosis connector.
(2) To check ABS system, remove the valve relay.
NOTE
That is because the valve relay is off and the warning
lamp remains illuminated if there is a fault in the ABS
system.
(3) Turn off the ignition switch.
(4) Read out a diagnosis code by observing how the warning
lamp flashes.
Indication of diagnosis code by warning lamp
When the diagnosis code No.24 is outputWhen no diagnosis code is output*
On
Off
1.5 secs.0.5 sec.
0.5 sec.
Pause
time 3
secs.Tens signalPlace
division
2 secs.Units signal
A03X0113
On
Off
0.5 sec. <MPI, A/T>
0.25 sec. <ABS>
NOTE
*: Even if the ABS system is normal, removing the valve relay causes the diagnosis code No.52 to
be output.
Engine warning lamp
(check engine lamp)

MPI – Troubleshooting13-7
1-3 ERASING DIAGNOSIS CODES
(1) Turn the ignition switch to OFF.
(2) After disconnecting the battery cable from the battery (–) terminal for 10 seconds or more, reconnect
the cable.
(3) After the engine has warmed up, run it at idle for about 15 minutes.
1-4 FAIL-SAFE FUNCTION REFERENCE TABLE
When the main sensor malfunctions are detected by the diagnosis function, the vehicle is controlled
by means of the pre-set control logic to maintain safe conditions for driving.
Malfunctioning itemControl contents during malfunction
Air flow sensor (AFS)(1) Uses the throttle position sensor signal and engine speed signal (crank angle sensor
signal) to take reading of the basic injector drive time and basic ignition timing from
the pre-set mapping.
(2) Fixes the ISC servo in the appointed position so idle control is not performed.
Intake air temperature
sensorControls as if the intake air temperature is 25C.
Throttle position
sensor (TPS)No increase in fuel injection amount during acceleration due to the throttle position sensor
signal.
Engine coolant
temperature sensorControls as if the engine coolant temperature is 80C.
(This condition is maintained until the ignition switch is turned off even when the sensor signal
returns normal.)
Camshaft position
sensor(1) Injects fuel to all cylinders simultaneously for 4 seconds.
(However, after the ignition switch is turned to ON, the No. 1 cylinder top dead centre
is not detected at all.)
(2) Lets the fan motor (radiator and condensor) run at high speed.
Barometric pressure
sensorControls as if the barometric pressure is 101 kPa {760 mmHg}.
Detonation sensorSwitches the ignition timing from ignition timing for super petrol to ignition timing for standard
petrol.
Ignition coil, power
transistorCuts off the fuel supply to cylinders with an abnormal ignition.
Alternator FR terminalDoes not control the output of the alternator according to an electrical load. (works as a
normal alternator)
Misfire
(Evolution-V only)Cuts off the fuel to the misfiring cylinder if a misfire that could damage the catalyst is detected.

MPI – Troubleshooting13-8
2. INSPECTION CHART FOR DIAGNOSIS CODES
Code No.Diagnosis itemReference page
12Air flow sensor (AFS) system13-8
13Intake air temperature sensor system13-9
14Throttle position sensor (TPS) system13-9
21Engine coolant temperature sensor system13-10
22Crank angle sensor system13-11
23Camshaft position sensor system13-11
24Vehicle speed sensor system13-12
25Barometric pressure sensor system13-13
31Detonation sensor system13-14
41Injector system13-14
44Ignition coil and power transistor unit system13-15
64Alternator FR terminal system13-16
3. INSPECTION PROCEDURE FOR DIAGNOSIS CODES
Code No. 12 Air flow sensor (AFS) systemProbable cause
Range of Check
Engine speed is 500 r/min or more.
Set conditions
Sensor output frequency is 3 Hz or less for 4 seconds.Malfunction of the air flow sensor
Improper connector contact, open circuit or
short-circuited harness wire of the air flow sensor
Malfunction of the engine-ECU
Measure at the air flow sensor con-
nector A-25.
Connect the connector. (Use
the test harness: MB991709)
1. Voltage between 3 and earth
(Engine: Idling)
OK:2.2–3.2 V
2. Voltage between 7 and earth
OK:0–1 V (Engine: idling)
6–9 V (2,000 r/min)
OK
Replace the engine-ECU.1. NG
Check the air flow sensor circuit.
2. NG
Measure at the engine-ECU con-
nector B-59.
Connect the connector.
Voltage between 19 and earth
(Ignition switch: ON)
OK:6–9 V
OK
Check the following connector:
B-59
OK
Check trouble symptom.
NG
Replace the engine-ECU.NG
Check the following connector:
A-25NG
Repair
OK
Check trouble symptom.
NG
NG
Repair
Replace the air flow sensor.

MPI – Troubleshooting13-15
Code No. 44 Ignition coil and power transistor unit systemProbable cause
Range of Check
Engine speed is approx. 50 – 4,000 r/min.
Engine is not being cranked.
Set conditions
Abnormal engine speed is detected due to misfiring by crank angle sensor. (One
of two coils fails.)Malfunction of the ignition coil
Improper connector contact, open circuit or
short-circuited harness wire of the ignition primary
circuit
Malfunction of the engine-ECU.
NG
Check the harness wire between the ignition coil and ignition switch
connector, and repair if necessary.
2. NG
OK
Replace the engine-ECU.
3. NG
NG
Check the following items.
Check the spark plugs and spark plug cables.
Check the compression pressure.
OK
Check trouble symptom.
OK
Check the following
connectors:
A-110, A-111NG
Repair
NG
Check the harness wire
between the engine-ECU
and ignition coil connec-
tor.NG
Repair
OK
Check trouble symptom.
Check the following
connector:
B-59NG
Repair
OK
Check trouble symptom.
OK
Measure at the ignition coil connectors A-110, A-111.
Disconnect the connector, and measure at the harness.
1. Voltage between 1 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 3 and earth (Engine: Cranking)
OK:0.5 – 4.0 V
3. Continuity between 2 and earth
OK:Continuity1. NGCheck the following
connectors:
B-65, B-76NG
Repair
Check the ignition coil. (Refer to Group 16 – Ignition System.)NG
Replace
Check the harness wire between the ignition coil connector and
earth, and repair if necessary.

MPI – Troubleshooting13-22
6. ENGINE-ECU INSPECTION
6-1 TERMINAL VOLTAGES
Engine ECU connector
Terminal
No.Check itemCheck condition (Engine condition)Normal condition
1No.1 injectorWhile engine is idling after having been warmed up,
suddenly depress the accelerator pedal
Momentarily drops
slightlyfrom 1114V
14No.2 injector
suddenly depress the accelerator pedal.slightly from 11 – 14 V.
2No.3 injector
15No.4 injector
3Fuel pressure control
valve
Ignition switch: ONBattery voltage
valve
Engine: Cranking to idling (within about two minutes)0 – 3 V to battery
voltage
4Stepper motor coil (A1)Engine: Immediately after engine has been started
f
or warming up
Changes repeatedly
f
rom battery voltage to
17Stepper motor coil (A2)
for warming upfrom battery voltage to
0 – 6 V and from 0 – 6
V to battery voltage5Stepper motor coil (B1)V to battery voltage.
18Stepper motor coil (B2)
6Secondary air control
solenoid valveIgnition switch: ONBattery voltage
8Fuel pump relayIgnition switch: ONBattery voltage
Engine: Idling0 – 3 V
10Power transistor unit
(A)Engine speed: 3,000 r/min0.3 – 3.0 V
23Power transistor unit
(B)
11Wastegate solenoid
valve
Ignition switch: ONBattery voltage
valve
Engine: At idle after having been warmed up (when
premium gasoline is used)0 – 3 V
12Power supplyIgnition switch: ONBattery voltage
25
19Air flow sensor reset
signal
Engine: Idling0 – 1 V
signal
Engine speed: 3,000 r/min6 – 9 V
20Fan motor relay (HI)Fan not operating (coolant temperature: 90C or
below)Battery voltage
Fan at high speed (coolant temperature: 105C or
above)0 – 3 V