Renault Megane, Scenic

Since 1996 of release

Repair and car operation

Fuel and exhaust systems - diesel models

Components of the fuel pump of high pressure Bosch

1 — the Electromagnetic valve of management depending on loading (ALFB) 2 — a valve Winding отсечки fuel 3 — the preheat/valve Microswitch recycling the fulfilled gases 4 — the Microswitch of the conditioner of air 5 — the Screw of adjustment of turns of delay	6 — the Screw of adjustment maximum turns 7 — the Screw of adjustment of idling 8 — the Screw of adjustment of fast idling 9 — the Electronic block of the coded valve

Components of the fuel pump of high pressure Lucas

1 — the Proof-reader of an advancing of injection 2 — the Proof-reader of pressure of pressurisation 3 — the Potentiometer of the lever of gas 4 — the Stopper of a control aperture of the moment of injection 5 — the Screw of adjustment of idling 6 — the Screw of adjustment of turns of delay 7 — the Electronic block of the coded valve	And — Weight In — + After ignition inclusion With — the Coded line D — Management of the proof-reader of an advancing of injection Е — + after ignition inclusion F — Weight G — the Signal of a control lever gas H — a Food 5В on a potentiometer of the lever of gas

The lever (arrow) of switching-off of fuel manually - ТНВД LUCAS

MODELS WITH ENGINE F8Q

The fuel system consists of a fuel tank, the fuel filter with a water-collecting sump, the fuel pump of a high pressure, atomizers and the components connected with them. At passage through the filter, fuel it is warmed up by a special element which is established in a filter casing. On engines F8Q 784 and 786 it is established турбокомпрессор. The Exhaust system - usual type, but on some models can be established system recycling the fulfilled gases and-or uncontrollable каталитический the converter which reduce quantity of harmful impurity in the fulfilled gas.
Fuel shakes from a fuel tank the fuel pump of a high pressure.
Before pump achievement, fuel passes through the fuel filter where it is cleared of alien subjects and water. Surplus of fuel greases rotating components of the pump, and then comes back in a tank (address to illustrations).
The fuel pump of a high pressure is resulted by a gear belt and rotates with turns, twice below turns коленвала.
On engine F8Q 620 fuel pump Bosch is established. The High pressure demanded for introduction fuel in compressed air in the chamber of combustion, is reached by the plate of a cam operating on the separate piston. Fuel passes through the central rotor with one exhaust outlet which is serially combined with target channels of injectors.
The fuel dosage copes a centrifugal regulator which reacts to position of a pedal of gas and turns of rotation of the engine. The regulator is connected with the dosing out valve which increases or reduces quantity of the fuel injected for each course of the pump.
The injection high light is established by manufacturers at pump installation. On the working engine the injection moment automatically is brought into accord with turns коленвала by means of the special mechanism turning кулачковую a plate or a ring.
The electromagnetic valve on the pump is used for short-term correction of the moment of injection during start from a cold condition.
The electromagnetic valve copes the block of management of system of preheat or the high-rise gauge. When the temperature of a cooling liquid is less 29°С, at engine start on a valve winding pressure of a food moves. If the gauge of temperature of a cooling liquid is defective, the further work of the valve will depend on temperature of air which is measured by a temperature-sensitive element established on the block of management. If both gauges are faulty, the electromagnetic valve automatically joins for 200 seconds at each start of the engine. On it the current through the relay which copes the high-rise gauge when surrounding pressure reaches 900 ± 20 мБар also moves.
On Engines F8Q 784, 786 and 788 fuel pump Lucas DPC is established.
This pump consists of the proof-reader of an advancing of the injection operated the electronic block. Fuel passes in the pump in a hydraulic head through the measuring valve connected with a rope of a pedal of gas and the proof-reader of pressure of pressurisation. The hydraulic head consists of two pistons directed to opposite sides kept together by rollers, moving in a ring. The injection moment is defined by a signal going from the gauge of lifting of a needle of 1st atomizer.
The separate device also is intended for increase in giving of fuel at increase of pressure of pressurisation.
Four fuel atomizers make fuel injection in the vortical chambers established in a head of the block of cylinders. Atomizers are calibrated in such a manner that open and closed only at certain pressure, providing effective ignition топливовоздушной mixes. The atomizer needle is greased with fuel which collects in the chamber of a spring and goes to a returnable hose of the fuel pump through taking away tube.
Start from a cold condition is helped by a heater or the candles of "heat" established in each vortical chamber (sm the Head an engine Electric equipment).
The system of fast idling copes a thermodrive or a vacuum drive, depending on model.
On models with a thermodrive of fast idling (engines F8Q), a temperature-sensitive element in cooling system operates the lever of fast idling on the fuel pump by means of a rope, increasing idling turns while the engine is not heated-up.
On models with a vacuum drive (engines F8Q 784, 786 and 788), the rope of fast idling copes a vacuum drive through the electromagnetic block. The electromagnetic block copes the block of management of preheat system, and on models with air conditioner there is an additional management from the relay муфты the compressor.
The valve отсечки stops fuel giving to a rotor of the fuel pump at the switched off ignition.
Under condition of diligent performance of the service specified in Specifications, the system of injection of fuel will long serve. The fuel pump can endure the engine. The main potential reason of damage of the fuel pump and atomizers - a dirt or water in fuel.
Service of the fuel pump and atomizers for the motorist is limited also performance of any works which have been not described in this Chapter, it is necessary to charge HUNDRED Renault or to the expert in systems of injection of fuel.

Because of a lack of specifications by the time of a writing of the given Management, following Sections only are partially applicable to engines F8Q 788. Therefore for большей information address on HUNDRED Renault.

MODELS WITH ENGINE F9Q

The device and action of system of the injection applied on engine F9Q - basically same, as at described above engine F8Q. The main distinction between two systems - regarding management of injection system. On engine F9Q, the dosage of fuel and the injection moment is supervised by an electronic control mean injection system (ECU). This system by an action principle is similar to a control system of the engine which is applied on petrol models and uses similar gauges to provide the electronic module of the data control, necessary for various operational modes of the engine. Gauges supervise temperature of a cooling liquid, air temperature, a fuel stream, turns of rotation of the engine, speed of the car, atmospheric pressure, temperature of fuel and position of a pedal of gas. On the basis of this data ECU operates the fuel pump, calculating quantity of injected fuel and the injection moment, preheat system, system recycling the fulfilled gases, иммобилизатором the engine of anticreeping system and остановом the engine.
Under condition of diligent performance of the service specified in Specifications, the system of injection of fuel will long serve. The fuel pump can endure the engine. The main potential reason of damage of the fuel pump and atomizers - a dirt or water in fuel.
Service of the fuel pump and atomizers for the motorist is limited also performance of any works which have been not described in this Chapter, it is necessary to charge HUNDRED Renault or to the expert in systems of injection of fuel.
If in injection system there is a malfunction, at first check up, that all electroconducting of system has been reliably connected and not oxidised. Also check up, that the filtering element of the air filter was pure, the compression in engine cylinders was in norm and hoses сапуна the engine have not been littered or damaged.
If after the specified checks malfunction remains, address on HUNDRED Renault which has possibility to check up system by means of diagnostic tester Renault XR25. The tester quickly also will simply define malfunction, eliminating requirement of check of all components of system separately that takes away a lot of time and can lead to damage ECU.

Working with components of fuel system, especially with fuel atomizers, it is necessary to observe some precautions. Preventions in the beginning of Sections see.