FL Fuel System

Precautions

Warnings:

When replacing or dismantling parts of fuel system, the following instruction must be followed.

■ Place a sign "prohibiting fireworks" in operation working position.

■ Work must be operated at good ventilation areas, and operation working position should be equipped with CO₂ extinguisher.

■ The drained fuel must be contained in container and covered well. Put this container in safe area.

■ When dismantling fuel pipeline fittings, please abide by the following steps:

——Release fuel pressure from fuel pipe.

——Disconnect negative cable of battery.

■ When installing, do not twist oil pipe.

■ Please conduct this operation on horizontal place.

■ After connecting oil pipe joint, make sure that the joint is installed firmly, and joint and resin pipe don't contact with adjacent parts.

■ Do not tighten pipe clip too much, to avoid hose damage.

■ After installing fuel pipe, please ensure whether fuel leaks from each connection through the following steps.

——Turn ignition switch to "ON" position and exert fuel pressure to fuel pipe (do not start), and then inspect whether there is fuel leaks from each connection.

——Start the engine and increase rotation speed, and inspect whether there is fuel leaks from each connection.

■ Because fuel may have leakage, please prepare container and cloth ahead of time.

■ Avoid open fire and spark.

■ Please keep the dismantled parts away from fire source.

■ Keep the connection clean and avoid damage or foreign matters entering. Please use plastic bag or similar articles to cover them well.

■ Only pure accessories of fuel system provided by JAC can be used.

Preparation Work

Special Tool:

Special Tool Table

No.	Tools	Overall diagram	Code	Descriptions
1	Fuel pressure gauge		JAC-T1F018	Measure fuel pressure
2	Tightening nut fixing disc.			Dismantle oil pump locked Nut

Fuel System

Assembly:

Fuel system assembly figure

1-carbon tank assembly 2-Fuel pipeline assembly 3-Fuel filter 4-Fuel pump 5-Fuel tank 6-gravity valve 7- Filler guard plate 8- Filler cap 9- Filling pipe assembly 10-Filling pipe shield

Fuel injector and Fuel Guide Rail

Dismantling:

1) Release fuel pressure in fuel pipe. ① Turn ignitions switch to "OFF" position, and dismantle negative cable of battery. ② Open fuel tank cover. ③ Put cloth or towel onto the pressure testing port of fuel guide rail, and press needle valve to release pressure.
2) Loose PCV hose joint from intake manifold. 3) Loose wire harness connector of air intake absolute pressure sensor and fuel injector. 4) Disconnect throttle connector. 5) Loose quick joint from fuel guide rail. ■ When taking it out, use cloth to absorb fuel leaked from fuel pipe.
6) Dismantle 2 fixing bolts of fuel guide rail. 7) Take fuel injector and fuel guide rail from air intake manifold. Check after Dismantle: 1) Injector: ■ Inspect whether upper and lower sealing ring of fuel injector have crack, ageing and damage. If yes, please replace it. ■ Inspect whether injection hole of fuel injector is blocked. If yes, use special equipment to clean or replace it.
2) Fuel guide rail ■ Inspect whether fuel detection port has damage or sticking. If yes, please replace it. ■ Inspect whether there is residual inside fuel guide rail. If yes, please replace it. ■ Inspect whether fuel guide rail has cracked or deformation.

Installation:

1) When installing a new O-ring onto the fuel injector, please pay attention to the following items:

■ The upper and lower O-rings are not the same. Please do not confuse

■ Use gasoline to lubricate O-ring.

■ Do not use other solvent to clean or lubricate O-ring.

■ When installing O-ring, pay attention not to let tool or fingernail scratch it. And pay attention not to twist or tensile O-ring.

2) Insert fuel injector into fuel guide rail, and install buckle in good condition. 3) Install fuel pipe guide rail and fuel injector assembly inside of intake manifold. 4) After this step, install it in reverse order of dismantling.

Check after Installed:

After installing, it is necessary to inspect whether fuel has leakage. The steps are shown as follows:

1) Put ignition switch to "ON" position (engine stops), and then inspect whether the connection of fuel pipe has leakage.

2) Start the engine and increase rotation speed, and then confirm whether the connection of fuel system has fuel leakage again.

Fuel Filter

Dismantling:

Note:

■ Fuel filter should be regularly replace according to the maintenance instructions shown in "Repair and Maintenance Manual". 1) Release fuel pressure in fuel pipe. See EM" discharge fuel pressure in the fuel pipeline". 2) Open fuel filler cap, and release pressure from fuel tank.

Note:

■ Use towel or similar articles to wrap fuel filter, to avoid residual fuel pressure spraying out.

3) Hold the side of joint, and then press the projection section of joint to push out fuel pipe.

4) If the joint sticks to resin pipe, push the joint for several times until it begin to move, and then push out joint.

5) Loose filter fixing screws from filter fixing bracket.

6) Take down filter assembly from the filter fixing support.

Inspect after Dismantled

■ Inspect whether filter assembly surface has scratch or serious deformation.

■ Inspect whether fixing screw has thread damage.

Installation: Please pay attention to the following items and install them according to the reverse order of dismantling. 1) Fuel filter ■ Pay attentions to fuel filter installation direction.

2) Connect Connector Connect the joint of fuel supply hose according to the following method: ① Inspect whether the connection has foreign matters or damage. ② Align joint with resin pipe, and then insert joint vertically into until a clip sound is heard. ③ After connection, confirm whether the following connections are in good condition according to the following methods. ■ Confirm whether two projection positions are connected with joint.

Check after Installed:

After installation, it is necessary to inspect whether fuel has leakage. The steps are shown as follows:

1) After the vehicle is lifted to proper height, turn ignition switch to "ON" position (engine stops), and then inspect whether the connection of fuel filter pipe has leakage.

2) Start the engine and run it at idle and high speed, re-confirm whether the connection of fuel filter has fuel leakage.

Fuel Gauge and Sensor Unit

Dismantling:

With the same methods as dismantling of fuel pump, take out fuel liquid sensor unit.

Inspection of Fuel Gauge Sensor Components:

1) Inspection of resistance:

① Inspect whether the resistance between fuel gauge sensor terminals is in standard range when the float of fuel gauge sensor component is located at F (MAX) and E (MIN) positions.

Comparison table of fuel gauge sensor resistance with instrument indication

Scale mark	Standard Resistance（Ω）
E	291±6
1/8（RED）	164±6
1/4	129±5
3/8	105±5
1/2	88±4
5/8	74±4
3/4	62±3
7/8	55±3
F	48±3

② When the float slowly moves between F (MAX) and E (MIN) positions, whether the resistance changes stably? 2) The float of fuel gauge sensor component moves and measure the height of A and B when float rod respectively touches with limit block F (MAX) and E (MIN).
■ Standard value: A：50±2mm B：130±2mm Disassembly: 1. Disconnect wire harness connector. ■ Because there is no limit release projection on wire harness connector, it is necessary to use fingers to hold the connector to pull it out.
2. Dismantle fuel level sensor unit according to the following methods: ① Use proper tool to pull up the projection section for unlocking as shown in figure. Note: ■ Pay attention not to damage it. ■ As shown in figure, it is an example about how to use hex spanner [2.0 mm(0.08 in)]
② After loosening fixing piece, slide out fuel level sensor unit according to arrow direction shown in figure. Assembly: 1. Inspect whether the mounting position of fuel level sensor unit on the side of fuel filter and fuel pump assembly has damage.
2. Slide fuel level sensor unit and align it with mounting groove, and then insert it until it stops. ■ Insert it until a "clip" sound is heard and you feel they are engaged. ■ After inserting, make sure that it can't be pushed out in reverse force.

3. Connecting harness connector.

■ Connect wire harness connector as shown in figure.

■ Stably insert wire harness connector until it stops.

Installation:

This installation is the same as installation methods of fuel pump.
Fuel Tank

Assembly:

Fuel tank system consists of many important parts such as filling pipe, fuel tank, canister, fuel pump, etc.

Fuel Pump

Fuel pump assembly drawing

Dismantling:

1) Inspect fuel level height shown on fuel gauge. If fuel gauge indicates full or locates at full position, drain fuel out of fuel tank until the level height shown in fuel gauge is lower than "E".

2) Release fuel pressure in fuel pipe.

3) Open fuel filler cap, release pressure from the fuel tank.

4) Dismantle oil tank service cover 5) Until it can be pried by slotted screwdriver.
6) Loosen wire harness connector of fuel pump components and oil pipe joint. ■ Wire harness connector of fuel pump component. ■ Hold the side of the joint, and press the projection position of joint to pull out the oil pipe.

■ If the joint sticks to resin pipe, pull and push the joint for several times until it begins to move, and then pull out the joint.

■ Keep the connection clean and avoid damage or foreign matters entering. Please use plastic bag or similar articles to cover them well.

7) Use special tool to loosen locknut and remove it.
8) Take down “Y” sealing ring.
9) Take out fuel pump. Note: ■ When taking it out, it is necessary to tilt fuel pump to avoid fuel level sensor damage. ■ Avoid residual fuel contamination, use cloth to wrap it and vertical draw it out.

Check after Dismantle:

1. Fuel Pump:

■ Inspect whether there is damage and fuel impurities. If yes, please replace or clean it.

■ Resistance inspection. Measure the resistance between two terminals of fuel pump, and the measured result should be about 2～30 Ω.

■ Output pressure inspection. Connect 12 V power supply and conduct trial running in gasoline. Observe whether there is fuel flowing out of fuel supply pipe of fuel pump and inspect whether fuel supply pressure can be kept.

■ Do not run it for a long time, to avoid pump core damage.

2. "Y" -ring

■ Inspect whether there is material shortage or damage.

3. Lock Nut

■ Inspect whether it has deformation, crack, material shortage or damage, and whether mounting thread has damage.

4. Fuel Level Sensor

■ Inspect whether the float is clashed, and whether the surface is oxidized.

Installation:

Install it in the reverse order of dismantling.

Inspect after Installed:

For inspection of whether there is fuel leakage, refer to "Inspection steps of fuel leakage".

Fuel Evaporation Drain System

Fuel evaporation system pipeline schematic diagram

1- Fuel tank 2- EVAP canister 3- EVAP canister electromagnetic valve 4- intake manifold

System Specification:

① The use of fuel evaporation system is to reduce the generation of hydrocarbon exhausting from fuel system into the atmosphere. Through the use of activated carbon in canister, the emission of hydrocarbon can be effectively reduced.

② Steam evaporated from fuel tank can be temporarily stored in canister through fuel tank steam control valve and steam pipe/ hose.

③ When the engine doesn't run or filling fuel into the fuel tank, the fuel evaporated from sealed fuel tank will be flew into the canister containing activated carbon and stored there.

④ When the engine runs, fuel steam in canister will be brought into the intake manifold through clean pipe. Canister clean control electromagnetic valve is controlled by ECU. When the engine is working, steam flow controlled by canister clean control electromagnetic valve will increase with the increase of air flow.

⑤ When the vehicle is at reduction speed or idle speed, canister clean control electromagnetic valve will close steam clean pipe.

⑥ Fuel steam control valve is riveted to the fuel tank, to prevent fuel steam emitting into the canister over the standard volume.

Fuel Evaporation Drain Pipeline Drawing:

Fuel evaporation system pipeline drawing

Note:

■ When installing vacuum pipe or clean pipe, do not use soap water or any other cleaning agent.

Inspection of Elements: 1）Canister : ① Position of canister: It is installed inside the engine compartment of the vehicle. ② Dismantling of canister: Dismantle two fixing bolts from canister housing, and take canister out.

③ Vacuum hose dismantle:

Use slip joint pliers to loosen clamp from canister to fuel tank and canister solenoid valve, and unplug vacuum hose.

2）Canister electromagnetic valve:

Opening of steam bypass pipe inside canister solenoid valve changes with air flow rate. Canister solenoid valve repeats switching on/ off (ON/OFF) according to the signaled sent from ECM, and valve opening will change, to achieve optimal engine control. Optimal value stored in ECM is determined by different engine conditions. When engine is running, air flow rate of fuel steam from canister will be adjusted with the change of air flow.

① component specification: Canister solenoid valve controls fuel steam flow rate in canister through the switching ON/OFF (ON/OFF) duty ratio. Canister solenoid valve is driven by signal of switching ON/OFF duty ratio sent from ECM. The longer the pulse width of opening (ON), the more the fuel steam passes through valve.
② Dismantling: a. Disconnect vacuum hose of canister solenoid valve. b. Disconnect canister solenoid valve harness connector. C. Take down the canister solenoid valve from holder.

3. Oil Filler Cap:

Filler is equipped with vacuum relief valve. When the pressure inside fuel tank is high (fuel steam is sufficient), vacuum relief valve will close, to prevent fuel steam from emitting to the atmosphere. When the pressure inside fuel tank is low (negative pressure), vacuum relief valve will open, to let the air into the fuel tank.

Inspection of Vacuum Degree at Drain Port:

① When the joint of throttle drain vacuum pipe is loosening from vacuum hose (black strip), connect a manual vacuum pump to the pipe joint.

② Start the engine and conduct inspect after increasing rotation speed of engine from no-load running condition, vacuum degree at drain port will increase with the increase of rotation speed of the engine. Note: ■ If the vacuum degree doesn't change according to this principle, it indicates that throttle drain port is blocked and should be cleaned.

Fault Diagnosis

This EFI system does not conduct fault diagnosis to injector itself, but conduct fault diagnosis to the drive grade of injector. When injector drive grade generates short-circuit or overload to battery voltage, grounding short-circuit or open-circuit, the system will memory fault code. At this moment, turn off oxygen sensor loop control and itself study pre-control, the last self-study data will be effective. After elimination of fault, fault code should also be cleaned.

Working pressure ：350 kPa

Injector resistance：11-16 Ω

Working temperature：-40～130 ℃

For another wires of fuel injectors are connected together, and engine main relay power supply ECU controls injector grounding.

Troubleshooting:

■ Fuel injector faults are mainly caused by long time use of engine, which causes fuel injector unsmoothness and bad pulverization. Regular cleaning injector.

■ Short-circuit, open-circuit of coils inside fuel injector may cause EFI system fault.

■ Whether system circuit has short-circuit or open-circuit.

■ Long time use of unqualified fuel causes fuel sticking to spray hole of fuel injector, which is easy to cause unstable idle speed fault.

Maintenance Data and Specification

Fuel System Specification Table

Item	Descriptions
Fuel tank capacity	80L
Fuel Pump
Working voltage	7～15 V
Rated working voltage	12 V
System pressure	350kPa
Flow	30～200 L/h (series product, selected according to maximum fuel consumption of engine).
Allowed working temperature range	-30℃～+70℃
Radio interference characteristic	2 Grade limited value (GB18655-2002)
Fuel injector
Working pressure	350kPa
Injector resistance	11-16Ω
Working temperature	-40℃～130℃