Haima M3. Service Manual

Electronic Fuel Injection Control System 1B

9. Normal starting but unstable idling speed or stalling when there is partial load (like
running of air conditioning)

Ordinary faulted parts: 1. Air conditioning system;2. Idling speed regulator;3. Fuel injector.

Ordinary Troubleshooting Flow:

No. Operation

Steps

Test

Results

Follow-up Steps

Yes

Overhaul the
intake system

Inspect if the air filter suffers blockage and if the intake port suffers
air leakage.

No Next

step

Yes

To step 4

Observe if the engine’s output power is increased when the air
conditioning is turned on, namely, use the electronic fuel injection
system’s diagnostic unit to observe the ignition advance angle, fuel
injection pulse width and intake volume.

No Next

step

Yes Next

step

Connect with the electronic fuel injection system’s adapter,
disconnect the ECU 75# pin’s connecting line, and inspect if there
is high-level signal at the wiring harness end after the air
conditioning has been turned on.

Overhaul A/C
system

Yes Next

step

Inspect if the A/C system pressure, compressor’s magnetic clutch,
and A/C pressure pump are normal.

Overhaul A/C
system

Yes

Fault
replacement

Dismantle the fuel injector, and use the dedicated fuel injector
cleaning analyzer to inspect if the fuel injector suffers leakage,
blockage, or excessive flow difference.

No Next

step

Yes Diagnosis

Help

Connect with the electronic fuel injection system adapter and turn on
the ignition switch, inspect if the power supply at 12#, 13#, 44#, 45#,
and 63# pin is normal, and inspect the electrical ground at 3#, 51#, 53#,
61#, and 80# pin is normal.

Overhaul
corresponding
lines

10. Normal starting but over high idling speed;

Ordinary faulted parts: 1. Throttle body and idling bypass air path;2. Vacuum tube;3. Idling speed
regulator;4. Coolant temperature sensor;5. Ignition timing.

Ordinary Troubleshooting Flow:

No. Operation

Steps

Test

Results

Follow-up Steps

Yes Adjust

Inspect if the throttle cable gets stuck or over-tightened.

No Next

step

Yes

Overhaul intake
system

Inspect if the intake system and connected vacuum tube suffer air
leakage.

No Next

step

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Electronic Fuel Injection Control System 1B

Yes

Overhaul the
intake system

Dismantle the idling speed regulator, and inspect if the throttle
body, idling speed regulator, and idling bypass air path suffer
carbon deposition.

No Next

step

Yes

Overhaul the
line or replace
the sensor

Pull out the coolant temperature sensor’s joint, and start the engine,
and observe if the engine has over high idling speed.

No Next

step

Yes Next

step

Inspect if the engine’s ignition timing accords with specification.

Overhaul
corresponding
lines

Yes Diagnosis

Help

Overhaul
corresponding
lines

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Electronic Fuel Injection Control System 1B

11. Rotating speed fails to increase or engine is stalled when being accelerated;

Ordinary faulted parts: 1. Water in fuel;2. Intake pressure sensor and throttle position sensor;3. Spark
plug;4. Throttle body and idling bypass air path;5. Intake port;6. Idling speed regulator;7. Fuel injector;8.
Ignition timing;9. Exhaust pipe.

Ordinary Troubleshooting Flow:

No. Operation

Steps

Test

Results

Follow-up Steps

Yes

Overhaul intake
system

Inspect if the air filter suffers blockage.

No Next

step

Yes Next

step

Connect with the fuel pressure gauge (front end of fuel
distribution pipe assembly’s inlet tube serves as the connection
point), start the engine, and inspect if the fuel pressure hovers
around 350kPa when being accelerated.

Overhaul the oil
supply system

Yes Next

step

Inspect every cylinder’s spark plug and observe if the model and
clearance accord with specification.

Adjustment or
replacement

Yes

Overhaul the
intake system

Dismantle the idling speed regulator, and inspect if the throttle
body, idling speed regulator, and idling bypass air path suffer
carbon deposition.

No Next

step

Yes Next

step

Inspect if the intake pressure sensor, throttle position sensor, and
the line are normal.

Overhaul the line
or replace the
sensor

Yes Fault

replacement

Dismantle the fuel injector, and use the dedicated fuel injector
cleaning analyzer to inspect if the fuel injector suffers leakage or
blockage.

No Next

step

Yes Fault

replacement

Step on the accelerator lightly and observe if the engine can be
easily started.

No Next

step

Yes Next

step

Inspect if the engine’s ignition sequence and ignition timing
accord with specification.

Overhaul
corresponding
lines

Yes Next

step

Inspect if the exhaust pipe can efficiently exhaust the air.

Repair or replace
the exhaust pipe

Yes Diagnosis

Help

Connect with the electronic fuel injection system adapter and turn
on the ignition switch, inspect if the power supply at 12#, 13#,
44#, 45#, and 63# pin is normal, and inspect the electrical ground
at 3#, 51#, 53#, 61#, and 80# pin is normal.

Overhaul
corresponding
lines

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Electronic Fuel Injection Control System 1B

12. Slow response when being accelerated

Ordinary faulted parts: 1. Water in fuel;2. Intake pressure sensor and throttle position sensor;3. Spark
plug;4. Throttle body and idling bypass air path;5. Intake port; 6. Idling speed regulator;7. Fuel injector;8.
Ignition timing;9. Exhaust pipe.

Ordinary Troubleshooting Flow:

No. Operation

Steps

Test

Results

Follow-up Steps

Yes

Overhaul intake
system

Inspect if the air filter suffers blockage.

No Next

step

Yes Next

step

Overhaul the oil
supply system

Yes Next

step

Inspect every cylinder’s spark plug and observe if the model and
clearance accord with specification.

Adjustment or
replacement

Yes

Overhaul the
intake system

Dismantle the idling speed regulator, and inspect if the throttle
body, idling speed regulator, and idling bypass air path suffer
carbon deposition.

No Next

step

Yes Next

step

Inspect if the intake pressure sensor, throttle position sensor, and
the line are normal.

Overhaul the line
or replace the
sensor

Yes Fault

replacement

Dismantle the fuel injector, and use the dedicated fuel injector
cleaning analyzer to inspect if the fuel injector suffers leakage or
blockage.

No Next

step

Yes Fault

replacement

Step on the accelerator lightly and observe if the engine can be
easily started.

No Next

step

Yes Next

step

Inspect if the engine’s ignition sequence and ignition timing
accord with specification.

Overhaul the
ignition system

Yes Next

step

Inspect if the exhaust pipe can efficiently exhaust the air.

Repair or replace
the exhaust pipe

Yes Diagnosis

Help

Connect with the electronic fuel injection system adapter and turn
on the ignition switch, inspect if the power supply at 12#, 13#,
44#, 45#, and 63# pin is normal, and inspect the electrical ground
at 3#, 51#, 53#, 61#, and 80# pin is normal.

Overhaul
corresponding
lines

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Electronic Fuel Injection Control System 1B

13. Poor performance or lack of power when being accelerated

Ordinary faulted parts: 1. Water in fuel;2. Intake pressure sensor;3. Spark plug;4. Ignition coil;5. Throttle
body ;6. Intake port;7. Fuel injector;8. Ignition timing;19. Exhaust pipe.

Ordinary Troubleshooting Flow:

No. Operation

Steps

Test

Results

Follow-up Steps

Yes Repair

Inspect if there are faults like clutch slippage, low tire pressure,
incorrect size of brake dragging tire, and incorrect four-wheel
positioning etc.

No Next

step

Yes

Overhaul the oil
supply system

Inspect if the air filter suffers blockage.

No Next

step

Yes Next

step

Connect with the fuel pressure gauge (front end of fuel distribution
pipe assembly’s inlet tube serves as the connection point), start the
engine, and inspect if the fuel pressure hovers around 350kPa
when being accelerated.

Overhaul the oil
supply system

Yes Next

step

Pull out one cylinder’s spark plug wire, and connect with
the spark plug, during which make the spark plug’s electrode keep
a distance of 5mm away from the engine body. Then start the
engine, and inspect if the HV spark’s intensity is normal.

Overhaul the
ignition system

Yes Next

step

Inspect every cylinder’s spark plug and observe if the model and
clearance accord with specification.

Adjustment or
replacement

Yes

Overhaul the
intake system

Inspect if the throttle body and air path suffer carbon deposition.

No Next

step

Yes Next

step

Inspect if the intake pressure sensor and throttle line are normal.

Overhaul the line
or replace the
sensor

Yes Fault

replacement

Dismantle the fuel injector, and use the dedicated fuel injector
cleaning analyzer to inspect if the fuel injector suffers leakage or
blockage.

No Next

step

Yes Fault

replacement

Step on the accelerator lightly and observe if the engine can be
easily started.

No Next

step

Yes Next

step

Inspect if the engine’s ignition sequence and ignition timing
accord with specification.

Overhaul the
ignition system

Yes Next

step

Inspect if the exhaust pipe can efficiently exhaust the air.

Repair or replace
the exhaust pipe

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Electronic Fuel Injection Control System 1B

14. Idle start/stop function ineffective

Ordinary faulted parts: 1. Engine compartment cover signal;2. Driver door signal;3. Clutch switch
signal;4.Neutral position signal;5. Accelerator pedal;6. Brake vacuum degree signal;7. Accumulator sensor.

Note: If the engine has been started, start/stop indicator blinks in yellow color and turns into yellow,
indicating the system has located relevant part faults, and the faults shall be diagnosed and repaired in the
repair factory.

Ordinary Troubleshooting Flow:

1. Start/stop indicator is green, but the engine cannot stop automatically

No. Operation

Steps

Test

Results

Follow-up Steps

Yes

System is right staying in the
normal “Automatic Stop
Prohibited” condition.

If it is in green indicator blinking state or turns into
yellow lamp now and then.

No Next

step

Yes

Inspect the accelerator pedal

Inspect if the idling speed is a little bit high after the
accelerator has been released, and the normal idling
speed should be 700 rpm(depending on specific
project).

No Next

step

Yes Next

step

After the engine stops, the gearbox stays in the
gear-engaging state, and then floor the clutch and turn
the key to observe if the engine can be started.

Overhaul the clutch switch

2. After a period of driving (coolant temperature surpasses 75 ), start/stop indicator remains yellow,

℃

and inspect if the accumulator temperature (ambient temperature) is excessively low (below 0 , specific

℃

temperature)

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Electronic Fuel Injection Control System 1B

Functional Requirements on ME788 System’s Diagnostic Unit

Functions required:

I. Self-diagnosis

Mostly including: read fault code, and clear fault code;

II. System Parameter Display

Mostly including: including: water temperature, air intake temperature, throttle opening, engine rotating
speed, ignition angle, A/F ratio short-term modification, A/F ratio long-term plus and multiplication
modification, intake pressure, intake flow, oxygen sensor signal, system voltage, and torque demand value
etc;

III. System Modes

Mostly including: display of 10 modes like programming, cooling system, stable working condition,
dynamic working condition, emission control, oxygen sensor, idling speed, fault indicator, emergency
operation, and air conditioning etc.

IV. Actuator Test

Mostly including: six function tests on fault indicator, fuel pump, air conditioning relay, fan control,
ignition test, and single-cylinder oil interruption;

V. System Initialization Resetting (self-adaption stop resetting)

After being stalled, engine will send the initialization directive, and the system will stop resetting previous
self-adaption.

VI. Speedometer

Mostly including: display of vehicle driving mileage and driving time;

VII. Version Information

Mainly including: display of car frame number (optional), ECU hardware number, and ECU software
number

Parts Mounting Torque Specification Table

No. Part

Name Mounting Torque (N·m)

Coolant temperature sensor

39.2 (Max)

2 Knock

sensor

20±5

3 Oxygen

sensor

50±10

Rotating speed sensor

10±2

5 Phase

sensor

10±2

6 Magnetic

fuel

injector

7 Electronic

accelerator

pedal

6±0.5

8 Electronic

throttle

(Max)

Brake vacuum degree sensor

10±2

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Electronic Fuel Injection Control System 1B

Electronic Fuel Injection System Maintenance Specification

Family Vehicle

Note:

1. This maintenance specification is only tailored to family vehicles;

2. Maintenance interval depends on the speedometer reading or time interval, and the one that expires first

shall prevail.

3. Maintenance specification is based on the presumption that the automobile is used according to the

normal design, and so it shall be strictly observed.

Mileage

x1000km

10 20 30 40 50 60 70 80

Items

Month

3 6 9 12 15 18 21 24

Ignition

Coil

I I I I

Ignition

Cam

I I I I

Ignition

Cap

I I I I

Ignition

Wire

I I I I

Spark

Plug

I I I R

Ignition

Timing

I I I I

Engine

Idling

Speed

I I I I

Fuel Tank

Fuel

Filter

R R R R

Fuel

Injector

C* C* C* C*

Air

Filter

I R I R

EWD or Stepper Air Bypass

Throttle

Body

C C C C

Emission

Check

I I I I

Check

Diagnostic

Tool I I I I

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Electronic Fuel Injection Control System 1B

Vehicle for Lease

Explanation:

1. This maintenance specification is applicable to the vehicle for lease;

2. Maintenance interval depends on the speedometer reading or time interval, and the one that expires

first shall prevail.

3. Maintenance specification is based on the presumption that the automobile is used according to the

normal design, and so it shall be strictly observed.

Mileage

x1000km

20 40 60 80 100 120 140 160

Items

Month

3 6 9 12 15 18 21 24

Ignition

Coil

I I I I I I I I

Ignition

Cam

I I I I I I I I

Ignition

Cap

I I I I I I I I

Ignition

Wire

I I I I I I I I

Spark

Plug

I R I R

Ignition

Timing

I I I I

Engine

Idling

Speed

I I I I

Fuel

Tank

C C

Fuel

Filter

R R R R R R R R

Fuel

Injector

C* C* C* C* C* C* C* C*

Air

Filter

I R I R I R I R

EWD or Stepper Air Bypass

Throttle

Body

I C I C I C I C

Emission

Check

I I I I

Check

Diagnostic

Tool

I I I I

Note: R-Replace

C-Clean

I- Inspect (Replace the spare parts when find out failure in inspection.)

C- The maintenance of fuel injector had better clean by a special tool -- fuel injector cleaner

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Fuel System 1C-1

Chapter 3 Fuel System

Table of Contents

Fuel System ·········································································································1C-2

Preparatory Work before Repair ···········································································1C-2

Inspection Work after Maintenance········································································1C-2

Inspection to Fuel Leakage ·················································································1C-2

Fuel Hose Mounting ·························································································1C-2

Warning on Plastic Fuel Pipe (fuel supply pipe assembly, fuel supply pipe,
and fuel return pipe assembly) ·············································································1C-3

Explanations on Plastic Fuel Pipe (Fuel Supply Pipe Assembly,
Fuel Supply Pipe, and Fuel Return Pipe) Mounting·····················································1C-3

Explanations on fuel filter dismantling /mounting ······················································1C-3

Cylinder Dismantling /Mounting ··········································································1C-4

Cylinder Air Tightness Test ·················································································1C-5

Inspection of Check Valve ··················································································1C-5

Inspection of Fuel Cylinder Pipeline Pressure ···························································1C-5

Inspection of Fuel Pressure Maintenance·································································1C-7

Fuel Pump Assembly Dismantling /Mounting ···························································1C-8

Inspection of Fuel Pump Assembly········································································1C-8

Inspection of Conducting/Non-conducting State ························································1C-36

Inspection of Open/Short Circuit ··········································································1C-8

Inspection of Fuel Pump’s Maximum Pressure ··························································1C-8

Inspection of Fuel Pump Oil Pressure Maintenance ····················································1C-9

Spray Nozzle Dismantling /Mounting·····································································1C-10

Inspection of Spray Nozzle ·················································································1C-10

Fuel Vaporation and Absorption System ········································································1C-10

Inspection of Carbon Canister Assembly ·································································1C-11

Inspection of Carbon Canister’s Electromagnetic Valve················································1C-11

Inspection of Ventilation Condition ·······································································1C-11

Inspection of Open/Short Circuit ··········································································1C-11

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Fuel System 1C-2

Fuel System

Preparatory Work before Repair

Warning

 Fuel vapor is dangerous and combustible,

which may lead to personnel injury and
property loss. Due to this, avoid spark or naked
flame at the place where there is fuel.

 Fuel overflow or leakage is dangerous, and the

fuel is combustible, which may lead to
personnel injury and property loss. In addition,
the fuel has side effect on the skin and eye.
Due to this, work safety rules shall be observed
during the working process.

Notice:

 Even if the engine does not run, fuel in the fuel

system still stays within the high pressure
state.

Work Safety Steps

1. Dismantle the oil cylinder head, and release

the pressure from the oil cylinder.

2. Pull out the fuel pump relay (located in the

electrical box at the centre of the engine
compartment).

3. Start

the

engine.

4. Restart the engine several times after the

engine stalls.

5. Turn the ignition switch to the “OFF” position.

6. Reload the fuel pump relay.

Inspection Work after Maintenance

Warning

 Fuel overflow or leakage is dangerous, and

also the fuel is combustible, which may lead to
personnel injury and property loss. Due to this,
follow the under-mentioned “Fuel Leakage
Inspection” to conduct inspection after
remounting the fuel hose.

Inspection to Fuel Leakage

Warning

 Fuel overflow or leakage is dangerous, and

also the fuel is combustible, which may lead to
personnel injury and property loss. Due to this,
fuel leakage shall be inspected frequently after
the engine stops.

Caution

 Wrong connection with other wiring terminals

may lead to fault, and so caution is needed
during the connection process.

1. Connect the DLC’s wiring terminal F/P with

the vehicle body (as the ground) with a
jumper wire.

2. Turn the ignition switch to the “ON” position

to run the oil pump.

3. Pressurize the oil circuit for at least five

minutes according to preceding method, so as
to inspect if there is leakage.

4. In the event that there is fuel leakage, inspect

if fuel hose and fuel pipe’s sealing faces
suffer damage. If necessary, replace them.

5. After the overhaul and remounting, repeat

Step 1 to Step 3.

Fuel Hose Mounting

1. Replace the damaged and distorted fuel hose,

fuel pipe, and pipe clamp.

2. Fuel hose shall be mounted 25mm {0.98in}

above the fuel pipe, and if the fuel pipe has
limit device, mount the hose till it contacts the
limit device.

3. Use the pipe clamp to clamp the hose within

the mounting range (see the figure below),
and prevent the clamp from nipping previous
nipping place.

Jumper Wire

Fuel Pipe

Limit Device

Fuel Hose

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Fuel System 1C-3

Warning on Plastic Fuel Pipe (fuel supply
pipe assembly, fuel supply pipe, and fuel
return pipe assembly)

Dismantling

 When dismantling the fuel pipe, pressure in the

fuel system will lead to ejection of fuel from
the fuel pipeline, and so oil cylinder head shall
be dismantled in advance according to
requirements while dismantling the fuel
pipeline, in order to release the pressure in the
oil cylinder and avoid personnel injury and
property loss.

Caution

 While dismantling the fuel pipeline, necessary

sheltering measures shall be adopted, in order
to avoid the fuel’s ejection onto your body.

1. If the quick plug assembly is equipped with

double-lock mechanism, loosen the quick
plug assembly’s double locks along the
direction illustrated in the figure.

2. Pinch locking devices on both sides of the quick

plug with fingers to remove the quick plug.

3. Repeat Step 1 and Step 2, and dismantle the

quick plug at the other end of the fuel pipeline
from the supporting pipeline.

Explanations on Plastic Fuel Pipe (Fuel
Supply Pipe Assembly, Fuel Supply Pipe,
and Fuel Return Pipe) Mounting

Notice

When mounting the new fuel supply pipe
assembly, assemble properly double locks on the
quick plug assembly.

1. Inspect the fuel pipeline and supporting

pipeline joint’s sealing faces and avoid their
damage and distortion. If necessary, replace
them.

2. If the quick plug O-ring is damaged or

disengaged, mount the new fuel pipeline.

3. Push the fuel pipeline quick plug into the

loading part till the pipe joint makes the
“click” sound.

4. If the fuel pipeline quick plug is equipped

with double-lock mechanism, mount the
double locks till there is “click” sound.

5. Pull the quick plug with hands to confirm if it

has been secured mounted.

Explanations on fuel filter dismantling
/mounting

Warning

 When dismantling the fuel pipe, pressure in the

fuel system will lead to ejection of fuel from the
fuel pipeline, and so cylinder head shall be
dismantled in advance according to requirements
while dismantling the fuel pipeline, in order to
release the pressure in the cylinder and avoid
personnel injury and property loss.

Caution

 While dismantling the fuel pipeline, necessary

sheltering measures shall be adopted, in order
to avoid the fuel’s ejection onto your body.

1. Complete the preparatory work before the

repair (See Preparatory Work before Repair).

2. Dismantle fuel filter from the longitudinal

beam on the left side of the bottom plate.

Loosen the cylinder fuel supply pipe and fuel
return pipe assembly along the direction illustrated
in the figure.

Avoid nipping previous nipping place

Double Locks

Locking Device (two sides)

Fuel supply pipe

Fuel filter

Fuel return pipe

assembly

Bolt

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Fuel System 1C-4

Caution

 To avoid the quick connector’s damage or oil

leakage, follow the “Explanations on plastic
fuel pipe dismantling” to complete the
under-mentioned work (see the Fuel System,
Explanations on Plastic Fuel Pipe Dismantling)

Dismantle fuel filter bracket’s mounting bolt, and
remove the fuel filter.

Mount parts according to the sequence reverse to
the dismantling process.

Caution

 To avoid the quick connector’s damage or oil

leakage, follow the “Explanations on plastic
fuel pipe mounting” to complete the
under-mentioned work (see the Fuel System,
Explanations on Plastic Fuel Pipe Mounting)

Cylinder Dismantling /Mounting

Warning

 Unwashed cylinder is dangerous and may lead

to combustion or explosion, which will further
result in serious casualties. Due to this,
cylinder shall be cleaned with vapor before the
overhaul.

 Fuel overflow or leakage is dangerous, and the

fuel is combustible, which may lead to
personnel injury and property loss. Due to this,
do not damage the sealing face while
dismantling/ mounting the oil pump assembly.

Caution

 Dismantling/mounting quick connector before

cleaning will lead to damage of the fuel pipe
and quick connector. Due to this, cleaning is a
must before dismantling /mounting, in order to
make sure that no foreign objects enter the fuel
pipe and connector.

1. Park the vehicle stably on the lifting machine.

2. Complete preparatory work before repair (see

Preparatory Work before Repair).

3. Loosen the accumulator’s negative cable.

4. Dismantle

the

second-row seats (see Part S,

Seat, Second-row Seats Dismantling
/Mounting).

5. Dismantle the cylinder repair cover plate.

6. Dismantle all fuel pipes that connect with the

oil pump.

7. Drain fuel in the cylinder.

8. Life the vehicle with lifting machine and

dismantle parts according to sequence
illustrated in the figure.

9. Mount parts according to the sequence reverse

to the dismantling process.

10. Complete inspection work after the repair (see

Inspection Work after Repair)

No.

Part Name

Tightening

Torque

(N·m)

1 Oil filling pipe cover

2 Assembling bolt

3.9～5.9

3 Dustproof cover

4 Elastic pipe clamp

5 Ventilation hose

6 Elastic pipe clamp

7 Oil filling hose

8 Anti-looseness bolt

8.8～12.7

9 Oil filling pipe assembly

10 Flange nut

43.1～60.8

11 Fuel tank mounting unit

12 Fuel tank mounting

13 Electric pump gland

75～85

14 Fuel pump assembly

15 Electric pump gasket

16 Fuel tank assembly

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Fuel System 1C-5

Cylinder Air Tightness Test

Notice

 Cylinder air tightness test is used to test the

welding quality between parts (like the upper oil
filling port, exhaust port, and gravity valve) and
the cylinder body.

1. Dismantle the cylinder mounting assembly

(see the Cylinder Dismantling/Mounting).

2. Block the special blanking plug (dedicated to

main fuel pipe) on the fuel pump assembly.

3. Use special blanking plug to block the gravity

valve vapor hose’s joint on the cylinder body.

4. Connect the special air pressure test tool with

the cylinder’s oil filling port and exhaust port.

5. Put the cylinder horizontally into the special

water tank dedicated to cylinder test (the total
cylinder shall be immersed 100mm below the
water surface).

6. Charge compressed air into the cylinder’s oil

filling port, and pressurize the cylinder to
(30～50)kPa. Then, maintain the pressure for
1min.

7. Inspect if there is air bubble between the parts

(like oil filling port, exhaust port, and gravity
valve) and the cylinder’s welding face.

 If there is air bubble on the welding face,

replace the cylinder (see Cylinder
Dismantling/Mounting)

Inspection of Check Valve

1. Dismantle the oil filling pipe assembly (see

Cylinder Dismantling/Mounting).

2. Confirm if the check valve’s bulge is aligned

with the oil filling pipe’s slot.

3. If they are not aligned, dismantle the check

valve, and remount it after the aligning.

4. Confirm if picking up the check valve again,

the check valve should be closed.

5. If it is open, replace the check valve (see

Cylinder Dismantling/Mounting).

6. Confirm if the check valve can be opened in

dead weight.

7. If it cannot be opened, replace the check valve

(see Cylinder Dismantling/Mounting).

Inspection of Fuel Cylinder Pipeline Pressure

Warning

 Fuel overflow or leakage is dangerous, and the

fuel is combustible, which may lead to
personnel injury and property loss. In addition,
the fuel has side effect on the skin and eye.

Caution

 Dismantling/mounting quick connector before

cleaning will lead to damage of the fuel pipe
and quick connector. Due to this, cleaning to
the quick connector’s contacting zone is a must
before dismantling /mounting, in order to make
sure that no foreign objects enter the fuel pipe
and connector.

Notice:

 The following tests can be conducted if

necessary

Bulge

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Fuel System 1C-6

1. Complete

preparatory

work before repair (see

Preparatory Work before Repair)

2. Loosen the accumulator’s negative cable.

Caution

 To avoid the quick connector’s damage or oil

leakage, follow the “Explanations on plastic
fuel pipe dismantling” to complete the
under-mentioned work (see the Fuel System,
Explanations on Plastic Fuel Pipe Dismantling)

3. Dismantle the main fuel hose (fuel supply

pipe assembly) from the main pipe (fuel rigid
pipe).

4. Connect the special tool’s quick connector

with the fuel distributor(fuel rail), and insert
the fuel supply pipe assembly onto the special
tool’s interface.

5. Remount the accumulator’s negative cable.

Caution

 Wrong connection with other wiring terminals

may lead to fault, and so caution is needed
during the connection process.

6. Connect the DLC’s wiring terminal F/P with

the Vehicle body’s earthing point GND with a
jumper wire.

7. Turn the ignition switch to “ON” position to

make fuel pump run, and measure the

pipeline’s maximum oil pressure.

Standard value

390～410kpa

8. Turn the ignition switch to the “OFF”

position and loosen the jumper wire.

 If the pressure is higher than the standard value,

inspect the fuel pump’s maximum pressure

 If the pressure is normal, inspect if the oil

return pipe and pressure regulator suffer
blockage.

 If the pressure is lower than standard value,

turn the switch handle and measure the oil
pressure’s variation (see the figure).

—If the oil pressure rises speedily, inspect the
pressure regulator.

—If the oil pressure rises slowly, inspect the oil
pressure’s maximum value.

 If the oil pump’s maximum pressure is normal,

inspect if the oil circuit between the oil pump
and pressure regulator suffers blockage.

9. Dismantle the special tool unit.

Caution

 To avoid the quick connector’s damage or oil

leakage, follow the “Explanations on plastic
fuel pipe dismantling” to complete the
under-mentioned work (see the Cylinder
Dismantling/Mounting, Explanations on
Plastic Fuel Pipe Dismantling)

10. Connect the main fuel hose (fuel supply pipe

assembly) and the main pipe (fuel rigid pipe)

11. Complete the inspection work after repair (see

Inspection Work after Repair).

Switch handle

To main pipe

Fuel distributor

Earthing
jumper

Switch handle

To main pipe

Fuel distributor

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Fuel System 1C-7

Inspection of Fuel Pressure Maintenance

Warning

 Fuel overflow or leakage is dangerous, and

the fuel is combustible, which may lead to
personnel injury. In addition, the fuel has side
effect on the skin and eye.

Caution

 Dismantling/mounting quick connector before

cleaning will lead to damage of the fuel pipe
and quick connector. Due to this, cleaning to
the quick connector’s contacting zone is a
must before dismantling /mounting, in order
to make sure that no foreign objects enter the
fuel pipe and connector.

Notice:

 The following tests can be conducted if

necessary

1. Complete

preparatory

work before repair (see

Preparatory Work before Repair)

2. Loosen the accumulator’s negative cable.

Caution

 To avoid the quick connector’s damage or oil

leakage, follow the “Explanations on plastic
fuel pipe dismantling” to complete the
under-mentioned work (see the Fuel System,
Explanations on Plastic Fuel Pipe
Dismantling)

3. Dismantle the main fuel hose (fuel supply pipe

assembly) from the main pipe (fuel rigid pipe).

4. Connect the special tool’s quick connector

with the fuel distributor (fuel rail), and insert
the main fuel hose (fuel supply pipe assembly)
onto the special tool’s interface.

5. Rotate the switch handle along the direction

illustrated in the figure.

6. Remount the accumulator’s negative cable.

Caution

 Wrong connection with other wiring terminals

may lead to fault, and so caution is needed
during the connection process.

7. Connect the DLC’s wiring terminal F/P with

the Vehicle body’s earthing point GND with a
jumper wire.

8. Turn the ignition switch to the “ON” position

for about 10s, in order to make the fuel pump
run.

9. Turn the ignition switch to the “OFF”

position and loosen the jumper wire.

10. Observe the oil pressure after 60 minutes.

 If the oil pressure is lower than the standard

value, observe the oil pressure’s variation
while rotating the switch handle

—If the oil pressure maintains unchanged, replace
the pressure regulator (see Pressure Regulator
Dismantling/Mounting)

—If the oil pressure is changed, inspect if the oil
circuit and spray nozzle suffer oil leakage.

Standard value:

≥250kpa(2.5kgf/cm2, 36psi)

Switch handle

To main pipe

Fuel distributor

Earthing
jumper

Switch handle

To main pipe

Fuel distributor

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Haima M3. Service Manual - part 6