The fuel injection system is a complex device with many elements. Its diagnostics and repair require special equipment, the use of complex multi-stage techniques and significant practical experience. Therefore, it is best to entrust diagnostics and repairs to specialized stations. Maintenance and repair Volkswagen cars with special equipment for this.

Central injection system Fuel Mono-Jetronic

The Mono-Jetronic fuel injection system provides electronic intermittent petrol injection during intake manifold. At the same time, the Mono-Jetronic system, unlike the Digifant and K-Jetronic injection systems, has one centrally located nozzle 4 () for all cylinders. The distribution of fuel to individual cylinders occurs, as in engines with a carburetor, through the intake manifold. Air is drawn in by the engine through the air filter and enters the injection device. In the injector housing there is a controlled flexible cable throttle valve 12. Opening angle throttle valve is fixed by the throttle potentiometer 8, and transmits a signal to the control unit 6, depending on the instantaneous value of the engine speed and determines the amount of intake air.

The control unit regulates the timing and amount of injection based on the measured air quantity and the engine speed data from the ignition system. The longer the injector is open, the greater the amount of fuel injected.

Additional sensors are responsible for correctly measuring the amount of fuel in different modes movement.

The throttle valve potentiometer 8 informs the control unit 6 about the position of the throttle valve at idle.

The control unit slightly opens or closes the throttle valve through the servomotor and thus maintains stable speed idle move.

Temperature sensor 14 on the coolant connector measures the engine temperature.

The air temperature sensor in the intake duct measures the air temperature.

The lambda sensor 15 measures the oxygen content in the exhaust gas stream. The control unit, at its signal, maintains the content of harmful emissions in the exhaust gases at the lowest level.

For vehicles with a catalyst, the composition of the exhaust gases is maintained at a level that provides the best afterburning in the catalyst.

Rice. 5.24. Arrangement of elements of the Mono-Jetronic injection system in engine compartment: 1 - injector; 2 - temperature controller; 3 - block ECU control; 4 – fuel burner; 5 - fuel pressure regulator; 6 - connector for the air heater entering the engine; 7 - control light; 8 - vacuum adjustment of the ignition timing; 9 - throttle potentiometer; 10 - lambda sensor connector; 11 - water reflector of the throttle valve potentiometer; 12 - temperature sensor of the injection system (blue); 13 - heater thermal switch in the intake manifold (red), 14 - throttle position potentiometer; 15 – air temperature sensor; 16 - solenoid valve of the filter with activated carbon (gray); 17 - solenoid valve; 18 – additional injector resistor; 19 - electrical connector of the throttle position potentiometer; 20 - throttle damper

Central injection system Fuel Mono-Motronic

The Mono-Motronic fuel injection system, unlike Mono-Jetronic, is made in one block. Thanks to the combination of the ignition system with the injection system, the ignition works better when various conditions engine operation. Most of the work carried out and instructions for the Mono-Jetronic system also apply to the Mono-Motronic.

The electronics of the control unit registers a malfunction in the injection system. This malfunction after the first occurrence, is recorded in the memory. At the same time, the control lamp on the additional panel lights up, signaling that the malfunction has been recorded. If the fault occurs only once, for example due to an unreliable contact, then it is still recorded in the memory of the control device.

Port injection system Digifanf fuel

Rice. 5.25. Fuel injection system: 1 – fuel tank; 2 - fuel pump; 3 - fuel filter; 4 - fuel distributor; 5 - pressure regulator; 6 - control unit; 7 - nozzle; 8 - nozzle for starting a cold engine; 9 – the screw of adjustment of turns of idling; 10 - throttle position potentiometer; 11 - throttle valve; 12 - air flow meter; 13 – temperature sensor; 14 – thermal time sensor; 15 - ignition distributor; 16 - idle speed regulator; 17 - battery; 18 - ignition switch; 19 - relay

The Digifant fuel injection system was developed by VW and is installed on engines with letter designation PB, PF, PG and 2E. Block 19 () controls the ignition and injection simultaneously. The injection part basically corresponds to the BOSCH L-Jetronic system. The Digifant fuel injection system injects fuel into the intake manifold ahead of each intake valve. Unlike Mono-Jetronic, the Digifant system has a separate injector for each cylinder.

Fuel is taken from the fuel tank 1 by the electric fuel pump 2 and is fed through the fuel filter 3 through the fuel line to the injectors 6, 10.

The pressure regulator 4 of the fuel line monitors the constant maintenance of pressure in the fuel system.

The vibration damper in the pressure regulator 4 reduces pressure fluctuations in the fuel return line.

Air is sucked in by the engine through the air filter, intake manifold and its volume is measured by the air flow meter 15.

There is a damper in the air flow meter housing, which is deflected during the passage of the air flow. The deflection angle of the damper serves as a measure of the air flow. From the potentiometer on the damper axis, the control unit receives signals corresponding to the position of the damper.

The control unit 19 regulates the time and amount of injected fuel according to the measured amount of air and engine speed. The longer the injector is open, the more fuel is injected. Additional sensors allow precise dosing of fuel in different operating conditions.

The fuel distributor 5 stabilizes the idle speed, especially when the engine is warming up, or if the engine is loaded with switched on electrical consumers.

The throttle position potentiometer 18 is located directly on the throttle valve shaft 12. It signals the control unit about the position of the throttle valve at idle and full power. This applies to the control of the fuel supply switch, since while the contacts of the idle speed regulator 13 are closed, at engine speeds exceeding 1500 min–1 (forced idling), the control unit must stop supplying fuel to the engine.

The lambda sensor installed in cars with a controlled catalyst measures the oxygen content in the exhaust gases and sends the corresponding electrical signals to the control unit. The control unit changes the quality air-fuel mixture so that the exhaust gases the best way burnt in the catalyst. If the sensor involved in the regulation process fails, the control unit switches to an emergency program, thereby preventing engine damage, but allowing you to continue driving. In this case, the ignition changes to a later one and the power and throttle response of the engine drops.

Rice. 5.26. Location of elements of the Digifant injection system in the engine compartment: 1 - throttle body; 2 - ignition switch TSZ-H; 3 - idle switch; 4 - control unit; 5 - open throttle switch; 6 - idle speed stabilization valve; 7 - lambda sensor connector; 8 - intake manifold; 9 - pressure control valve; 10 - ignition coil; 11 - coolant temperature sensor (black); 12 - ignition distributor, 13 - injection system temperature sensor (blue); 14 - nozzles; 15 - knock sensor; 16 - fuel distributor; 17 - CO adjustment screw; 18 - air filter; 19 - air flow meter; 20 - pressure regulator; 21 - idle speed adjustment screw; 22 - air intake

K-Jetronic multipoint fuel injection system

Rice. 5.27. K-Jetronic injection system: 1 – fuel tank; 2 - fuel filter; 3 – fuel accumulator; 4 - fuel pump; 5 - storage battery; 6 - ignition switch; 7 - switch fuel pump; 8 - ignition distributor; 9 - thermal switch; 10 - cold engine start valve, 11 - spark plug; 12 - nozzle; 13 - inlet pipe; 14 - air valve for starting a cold engine; 15 - throttle body; 16 - throttle valve; 17 - air flow meter; 18 - measuring plate; 19 - plug; 20 - fuel distributor; 21 - engine warm-up valve; 22 – piston of the fuel distributor; 23 - pressure regulator; 24 – gauge plate lever; 25 - thrust lever of the fuel distributor piston; 26 - screw for adjusting the quality (composition) of the mixture; 27 - screw for adjusting the amount of the mixture

Rice. 5.28. Location of elements of the K-Jetronic injection system in the engine compartment: 1 - pressure sensor; 2 – the screw of adjustment of turns of idling; 3 - throttle position sensor; 4 - ignition switch TSZ-H; 5 - control unit; 6 - throttle body; 7 - ignition distributor; 8 - ignition coil; 9 - idle speed stabilization valve; 10 - control unit for idle speed and fuel cut-off; 11 - temperature sensor and thermo-time sensor; 12 - cold start valve; 13 - heating valve; 14 - crankcase breather; 15 - nozzle; 16 - damper for heating the air entering the engine; 17 - fuel distributor; 18 - screw for adjusting the CO content; 19 - air filter; 20 - fuel cut-off valve

The K-Jetronic fuel injection system is a mechanical sequential fuel injection system into the intake manifold before intake valves. The fuel is taken from the fuel tank 1 (), located in it by the supply fuel pump and the main fuel pump 4, and is supplied through the fuel accumulator 3 to the fuel filter 2, to the fuel distributor 20. The fuel distributor distributes and supplies fuel to the cylinders through the injectors 12 according to the amount measured air. Additional sensors allow you to accurately dose fuel at various temperatures and operating conditions ().

The fuel accumulator holds the fuel under pressure for a long time, even after the engine is turned off, which prevents the formation of bubbles and improves hot engine starting.

The fuel pump switch 7 (see) supplies current to the fuel pump 4 and the engine warm-up valve 21. The fuel pump switch interrupts the power supply to the pump when the ignition is turned off and there are no ignition pulses (engine off, ignition off). In addition, the switch interrupts the fuel supply when the engine exceeds the maximum speed.

When starting a cold engine, the cold start valve 10 injects additional fuel into the intake manifold to facilitate starting.

The thermal switch 9 regulates the injection duration of the cold start valve 10.

The pressure regulator 23 maintains the pressure in the system at about 470–540 kPa.

The warm-up regulator enriches the mixture during warm-up.

The electrical control unit controls the valves for shutting off the fuel supply and stabilizing the idle speed.

KE-Motronic multipoint fuel injection system

The KE-Motronic fuel injection system is combined system ignition and injection, with a common control unit. The nozzles are mechanically arranged in the same way as in the K-Jetronic system (see), but additionally have electronic control. Thanks to electronics, the amount of injection is controlled using additional sensors that collect and process information more fully and faster. In addition, lambda control during catalyst operation is facilitated. When using the KE-Motronic system, there is no need for a warm-up controller, shut-off valve and pressure control system.

The electronic control unit regulates the dose of fuel in various operating modes of the engine through an electro-hydraulic pressure regulator, which is located on the fuel quantity distributor. This means that the control unit monitors the richness of the mixture during cold start and engine warm-up, the richness of the mixture during acceleration and full power. In addition, it blocks the access of fuel when coasting.

The diaphragm pressure regulator, on the fuel quantity distributor, maintains the pressure in the system from 610 to 660 kPa.

The activated charcoal filter prevents harmful fuel vapors from escaping from the fuel tank into the atmosphere, evaporating fuel accumulates in the activated charcoal tank. When moving, the vapors are again fed into the engine for combustion under the control of two solenoid valves.

The memory device in the control unit recognizes the malfunction that has occurred and records it. If an important sensor fails, the control unit switches to a backup program (using average codes) so that the engine does not stop.

Rice. 5.30. Location of elements of the KE-Motronic injection system in the engine compartment: 1 - lambda sensor connector; 2 - throttle body; 3 - control unit; 4 – pipe for measurement of CO content; 5 - idle speed stabilization valve; 6 - output block; 7 - ignition coil; 8 - distributor with Hall sensor; 9 - fuel pump relay; 10 - sensor connection, ignition timing; 11 - knock sensor connector; 12 – temperature sensor; 13 - cold start valve; 14 - knock sensor 1; 15 - injector; 16 - knock sensor 2; 17 - damper for heating the air entering the engine; 18 - pressure regulator; 19 - fuel distributor; 20 - carbon filter; 21 - air filter; 22 - potentiometer; 23 - pressure regulator; 24 - air flow meter; 25 - valve carbon filter; 26 - spark plug; 27 - throttle position sensor

Simos engine management system

The device and principle of operation of the Simos engine management system are similar to the Digifant system.

Rice. 5.29. Arrangement of elements of system by the Simos engine: 1 – the electromagnetic valve of a canister of charcoal; 2 – air flow meter; 3 - oxygen sensor connector; 4 - throttle body; 5 - block ECU; 6 - injector; 7 - fuel pressure regulator; 8 - ignition coil; 9 - speedometer drive sensor; 10 - knock sensor connector; 11 – wire harness connector; 12 - speed sensor crankshaft engine; 13 – a socket of the gauge of frequency of rotation of a cranked shaft of the engine; 14 - ignition distributor; 15 - coolant temperature sensor; 16 - knock sensor; 17 - ground connection; 18 - temperature sensor of the air entering the engine; 19 - charcoal filter

Injection Device Precautions

When removing and installing elements of injection systems, it is necessary to observe following rules:

– do not start the engine at unreliably connected storage battery. Connectors of the ignition and injection system disconnect or connect only when the ignition is off. This also applies to measuring instruments;

- starting with a starting device is only permissible for no more than 1 minute, at a voltage of no more than 16.5 V;

- do not disconnect battery from onboard network when the engine is running, this can lead to failure of the control unit;

- before checking electronic system injection, you need to make sure that the ignition system is working, which means that the ignition and candles must correspond technical requirements;

– when working on the injection system, be careful to prevent dust and dirt from entering the various components of the system. It is not recommended to use compressed air or fluffy cloths to clean the system.

Checking and adjusting idle speed (XX) and mixture quality

A tachometer and analyzer are required to check and adjust idle speed and mixture quality. exhaust gases.

Preparation for adjusting the speed of the twentieth and the quality of the mixture run as follows:

- check and adjustment is carried out on a warm engine with a correctly set ignition moment and working system release of the fulfilled gases;

– start the engine and let it idle until the oil temperature reaches 80°C. At the same time, make sure that the temperature of the coolant does not exceed normal, since the fan must be turned off during the check and adjustment;

- turn off the engine, turn off all consumers of energy (headlights, radio, air conditioning, etc.);

– Disconnect and plug the crankcase ventilation hose;

– connect the control tachometer and gas analyzer;

– if the fuel lines were disconnected from the injectors or replaced with new ones before checking and adjusting the idle speed, increase the frequency to 3000 min–1, then leave the engine to idle for 2 minutes before starting the check and adjustment;

– The throttle must be in the idle position.

Adjustment of the idle speed and the quality of the mixture of the injection system Digifant fuel

– With the ignition off, connect the tachometer and the exhaust gas analyzer in accordance with the manufacturer's instructions;

– Start the engine and let it idle for one minute, then disconnect the blue connector from the temperature sensor 20;

– Using the accelerator control cable, open and close the throttle three times. When opening the throttle, the engine speed must exceed 3000 min-1;

- put the engine in idle mode, and check the idle speed, and the quality of the mixture (). To adjust, remove the plug and with the appropriate tool, turn the idle speed adjustment screw 1 and the mixture quality adjustment screw 2 (CO);

– Connect the temperature sensor connector, then sharply open the throttle three times (exceeding 3000 min-1), transfer the engine to idle and re-check the idle speed and the quality of the mixture (CO);

– at connection of a hose of ventilation of a crankcase the content WITH can increase;

– on the PF engine, check the lambda sensor: disconnect the pressure regulator hose from the throttle body, the CO content should increase momentarily, then decrease to a normal value;

– If the idle speed and CO content are satisfactory, reinstall the hoses and disconnect the tachometer and gas analyzer;

- if the adjustment does not give positive effect, check the idle switch (vehicles with mechanical box gear) or throttle position potentiometer (vehicles with automatic transmission gears) on special equipment.

Adjustment of the idle speed and the quality of the mixture of the Mono-Jetronic fuel injection system do it in the following order:

– Start the engine in the idle speed mode;

– Check up, turns of idling and the maintenance WITH;

– if the idle speed and the CO content differ from those required, check that the vacuum hoses are not cracked or damaged and are securely fastened;

– Check the valve of the carbon filter system. If it is OK, have the injection system checked by a workshop, as this requires a specialized diagnostic equipment, connected to the socket of the fault memory system. Adjustment of turns of idling or the content WITH is not made.

Adjust the idle speed and the quality of the mixture of the K-Jetronic fuel injection system in the following order:

– disconnect the crankcase ventilation hoses 1, 2 () from the breather on the side of the cylinder block, then disconnect the small diameter crankcase ventilation hose together with the calibrated connector 4 from the hose large diameter;

– turn on the ignition, the idle speed control valve should make noise and vibrate;

– Connect a tachometer and an exhaust gas analyzer in accordance with the manufacturer's instructions;

– if necessary, the position of the plate can be adjusted by bending the fastening bracket 2 under the plate (see );

for KE-Motronic fuel injection system:

– check initial position air flow meter plates. The upper part of the plate should be 1.9–3.0 mm lower, a = 1.9–3.0 mm (see) of the upper edge of the diffuser;

– if adjustment is necessary, remove the cover air filter and remove the filter element from the filter housing;

- check the value freewheel air flow meter plates. Engage the starter for 10 seconds, then slightly raise the air flow meter plate until you feel some resistance. The minimum free play should be 0.5 mm, and the maximum - 3.0 mm to the edge of the diffuser ();

– adjustment must be made at the fuel distributor by turning the locking screw of the control plunger. The distance from the locking screw to the shoulder of the nut 1 must be 0.6 mm ( and ). A quarter turn of the screw corresponds to 1.3 mm of insert travel. To increase the free play, screw in the locking screw, and to decrease it, unscrew it;

– Re-check idle speed;

– If the air flow meter or fuel distributor has been replaced, it is necessary to carry out the basic setting of the air flow meter adjusting lever. To do this, using a depth gauge, measure the distance between the contact surface of the fuel distributor and the tip of the adjustment lever (see), which should be 18.7–18.9 mm. To adjust, turn the CO content adjustment screw, but note that further adjustment of the CO content screw will change the initial setting.

nozzles

Checking the injectors of the Digifant fuel injection system do it in the following order:

- disconnect the voltage supply connector to the injectors, connect a probe with an LED to the connector and turn on the starter ();

- when the starter is running and normal voltage, the LED will flicker. If it is constantly on, replace the electrical wires from the battery to the gearbox and the ground bus of the Digifant control system;

– if the LED is off, check the status electrical wires control unit and injector. Measure the resistance of the injector power wires by connecting the connector to measuring instrument. If the resistance is 3.7–5.0 ohms, then the injectors are in normal condition. If resistance is greater than 5.0 ohms, check each injector and connector individually. The resistance of each nozzle is 15-20 ohms, and in the connector - no more than 0.5 ohms;

– the quality of spray nozzles can only be checked at a service station using special equipment

Removal and installation of nozzles of the Digifant fuel injection system do it in the following order:

– Disconnect a wire from the negative plug of the storage battery;

Rice. 5.45. Fuel line and nozzles of the Digifant fuel injection system: 1 - hose for fastening the fuel pressure regulator; 2 - bolt; 3 - fuel pressure regulator; 4 - supply fuel line, 5 - return fuel line; 6, 7 - bracket; 8 - insert; 9 - sealing ring, 10 - bolt; 11 - bracket; 12 - cable harness case; 13 - fuel line; 14 - nozzle; 15 - fuel hose; 16 - pressure control valve; 17 - connector; 18 - coolant temperature sensor; 19 - temperature sensor of the fuel injection system; 20 - connector; 21 - hose

– Remove the pressure in the fuel system. Unscrew the fuel pressure regulator 3 from the fuel line. Disconnect supply 4 and return 5 fuel lines from regulator 3 and fuel line;

– unscrew the bolts 10 fastening the fuel line to the cylinder head and remove the fuel line together with the injectors;

– Disconnect connectors from injectors 14;

- Loosen bracket 11 for fastening each injector and remove the injectors from the fuel line;

– Install in the reverse order of removal.

Checking the injectors of the fuel injection system K-Jetronic and KE-Motronic do it in the following order:

– injectors can only be checked at a service station using special equipment.

Removal and installation of nozzles of the fuel injection system K-Jetronic and KE-Motronic do it in the following order:

Rice. 5.46. Elements of the K-Jetronic fuel injection system: 1, 5, 9 - electrical connecting blocks; 2 - sealing ring; 3 - fuel line from the fuel pump; 4 – a tube of discharge of fuel in a fuel tank; 6 - thermal switch of the cold engine start valve; 7 - branch pipe of the cooling system; 8 - engine warm-up valve; 10 - pressure regulator; 11 - adjusting washer; 12 – fuel distributor; 13 - air flow meter; 14 – piston of the fuel distributor; 15 - sealing ring; 16 - plug; 17 - screw for adjusting the quality (composition) of the mixture; 18 - nozzle; 19 - inlet pipe; 20 - gasket; 21 - cold start valve

– switch off the ignition and release the pressure in the fuel system, to do this, loosen the fastening of the fuel line bolt to valve 21 (see ) to start a cold engine;

– Collect the spilled fuel with a rag and tighten the bolt;

– unscrew the connecting nut, loosen the hose of the fuel injection system on the injector 18 and remove the injector from the rail on the cylinder head;

- unscrew the nut and disconnect the nozzle from the fuel line;

– to unscrew the injector from the cylinder head, use special tool VW 3135;

– Installation is carried out in the reverse order of removal, but when installing the nozzle, first moisten the sealing ring 2 in gasoline.

System elements Digifant fuel injection

Idle speed stabilization valve check do it in the following order:

– the idle speed stabilization valve is installed behind the throttle body (). If, when the ignition is turned on, the valve vibrates and makes noise, then it is working;

- disconnect the electrical connector from the valve and measure the resistance with a tester, which should be 3.5–4.5 Ohm;

- if the valve is in good condition, then there is damage in the electrical wiring to the valve or in the control unit.

Lambda sensor test do it in the following order:

– connect the gas analyzer to the measuring tube;

– Start the engine in idle mode and let it run for 2 minutes, then check the CO content;

– Disconnect the hose from the pressure regulator 20 (see ) on the throttle body and close it tightly. In this case, the CO content should increase for a short time, and then return to the measured level;

– if the value of the CO content does not decrease, disconnect the lambda sensor and the connector for the sensor heating wires (). Connect the wire between the lambda sensor block and in turn to the negative and positive terminals of the battery (). The CO content should increase and decrease alternately. If the CO content is not correct, the control unit or electrical wiring is damaged and must be checked by a workshop;

– Disconnect the gas analyzer and connect the hoses and connectors.

Checking engine braking and enrichment at wide open throttle do it in the following order:

– engine braking and enrichment at wide open throttle are linked via the control unit;

– start the engine at idle speed, then open the throttle valve 1 () and insert a screwdriver 2 so as to increase the engine speed to 2000 rpm. The engine speed must change as the engine braking system works;

– if the engine braking system does not work, disconnect the electrical connector from the temperature sensor (blue), then connect the connector pins with a piece of wire. If the engine speed fluctuates, the temperature sensor is faulty and needs to be replaced;

– if the engine speed still does not change, reconnect the temperature sensor connectors and check electrical wiring temperature sensor or throttle switch. If they are in working condition, then the control unit is damaged.

Elements of the fuel injection system Mono-Jetronic

Checking the idle switch/control valve do it in the following order:

– switch on the ignition, open and close the throttle valve. Control valve 7 () should operate twice. Otherwise, disconnect the electrical connector and connect an LED probe to the connector. When the throttle is closed, the LED probe will light up, when the throttle is open, it will turn off;

– start the engine at idle speed, then disconnect the connector and reconnect it. The engine speed should increase and then decrease. Otherwise, replace the control valve;

– Switch off the ignition, disconnect the electrical connector from the throttle position device;

– using additional wires, connect the battery poles to the clamps of the throttle position device, while the rod 2 should move 2.5 cm, then disconnect the wires;

– connect the tester to the lower contacts of the electrical connector 2 (see ). When inserting the probe, the switch must be open, and after removing the probe, the switch must be closed (0 ohm).

Resistor test do it in the following order:

- connect the tester to the connector pins, the tester should show the presence of a resistance of 3-4 ohms.

Checking the throttle damper(vehicles with manual transmission) proceed in the following order:

– check that when the throttle is closed, the lever 1 (see) moves the rod 2 in the shock absorber 3 by 4 mm;

– otherwise, loosen the regulator nut 4 and install the shock absorber so that the lever just touches the stem;

– From this position, turn the shock absorber 4 1/4 turns towards the lever.

Checking the pressure regulator do it in the following order:

- due to the use of special equipment, the check must be carried out at a service station.

Charcoal filter check do it in the following order:

– Connect the tester to the black electrical connector 1 and turn on the ignition;

- the tester should show a voltage of 12 V;

– repeat the same operation with the gray electrical connector 2;

- for check solenoid valve 3 turn on the ignition and check that the valve is closed;

– When the ignition is switched off, the valve must open;

– The efficiency of the carbon filter system depends on the correct functioning of the Mopo-Jetronic control unit, lambda sensor and other elements. Due to the use of special equipment, the check must be carried out at a service station.

System elements fuel injection K-Jetronic

And the thermo-time switch, perform in the following order:

– disconnect the electrical plug from the cold start valve and connect the LED probe to the contacts ();

– Disconnect the electrical plug from the thermal switch and connect the contacts of the green-white wire () to ground. Do not connect the contact of the red-black wire to the "ground";

– Connect the electrical connector to the switch, leaving the green-white wire connected to ground;

- remove the cold start valve and insert it into glass jar. Turn on the starter, an even stream in the shape of a cone should come out of the valve ();

– wipe the valve and dry it for 1 min;

– with the cold start valve installed, but the wire contact disconnected, connect the LED probe to the two connector pins;

– turn on the starter for 10 s, the LED probe, depending on the temperature of the thermo-time switch, will light up for 1–8 s;

- the dependence of the duration of the LED on the probe on the temperature of the coolant is shown in the diagram ().

Checking fuel enrichment in cold engine acceleration mode do it in the following order:

– fuel enrichment in the cold engine acceleration mode works only when the start fuel supply mode switch, the diaphragm pressure sensor and the throttle switch are closed;

– Disconnect the electrical plug from the cold start valve and connect the LED probe to the pins in the connector. Start the engine in idle mode, while the LED probe should not light up;

– quickly open the throttle, while the LED probe should light up briefly (for 0.4 s).

Diaphragm pressure sensor check do it in the following order:

– Disconnect the electrical plug from the pressure sensor;

– Start the engine in idle mode;

connect the tester to two contacts on the switch, while the resistance should be equal to infinity, i.e. contacts are open;

quickly open the throttle, and the resistance should briefly decrease.

Do it in the following order:

– connect the tester to two contacts;

- with the throttle closed, the resistance should be equal to infinity;

– Slowly open the throttle until the switch contacts click. At this point, the resistance should be infinity, and the gap between the idle speed limiter and the throttle lever should be 0.1 mm ();

Heater check do it in the following order:

- Disconnect from the ignition coil and connect to ground high voltage wire;

– disconnect the electrical plug 2 () from the heater and connect the LED probe to the contacts in the connector;

- turn on the starter, while the LED probe should light up;

– check the resistance of heater element 1, which should be 20–26 ohms.

Checking the main throttle setting do it in the following order:

– The adjusting screw is set at the factory and does not require adjustment. If the screw has loosened, the following adjustment must be made:

- loosen the nut 1 (), unscrew the adjusting screw so that a gap is formed between the screw and the limiter, then turn the screw clockwise until it touches the limiter;

- the moment of contact can be determined using a sheet of thin paper inserted between them. From this point, turn the screw further by half a turn;

– Apply anti-twist fluid to the thread of the nut and tighten the nut;

– After adjustment, check the idle speed.

Elements of the fuel injection system KE-Motronic

Lambda sensor test do it in the following order:

- warm up the engine to operating temperature, and let it idle for two minutes;

- note the current in the control circuit, then pinch the hose 1 (). The current in the control circuit should decrease. Otherwise, disconnect the wires of the lambda sensor 2 and close the wire of the control unit to ground for twenty seconds. If the current in the control circuit changes, then the lambda sensor is faulty.

Checking the engine braking system do it in the following order:

– turn on the ignition, while the current in the circuit must be positive and be 90-110 mA. Otherwise, reverse the connection polarity of the connecting wires;

– start the engine and increase the speed to 3000 min–1;

– quickly close the throttle, while the current in the control circuit should change to negative for a short time.

Checking the cold start valve do it in the following order:

– Disconnect an electric socket from the gauge of temperature;

– Connect a 15 kOhm resistor in series to the connector;

– remove the cold start valve 13 and insert it into a glass jar;

- turn on the starter, an even jet in the form of a cone should come out of the valve;

– wipe the valve and dry it for a minute.

Throttle switch test do it in the following order:

– Disconnect the electrical plug 2 (see ), connect the tester to the throttle switch. Check that the resistance between the two pins is 0 ohm when throttle is closed, and infinity when throttle is open;

– Check up the moment of switching of the switch of turns of idling, slowly opening and then closing a butterfly valve. Operation should occur with a gap between the throttle lever and the control lever equal to 0.15–0.5 mm. If the clearance is not as specified, insert a 0.10 mm feeler gauge between the levers, loosen the switch 1 screws (see ), then move the switch so that the actuation torque is slightly higher. Tighten the screws and check the adjustment.

Diagnostics

Volkswagen Passat B3- popular car, its reliability, ease of maintenance, long term operation and spaciousness deserving best reviews many experienced drivers. Captivating with its durable, corrosion-resistant body and reliable engine, he, despite his age, remains a frequent guest on the roads. Naturally, even this quality car does not do without various breakdowns.

Engine problems can be very diverse, depending on various reasons. So, floating values ​​​​of engine speed, when the speed starts to decrease while driving, may be associated with malfunctions in the multi-injection. It also happens that due to malfunctions of the single-injection Passat b3 does not start at all. A later article will describe how to set up the Passat v3 single injection.

Fault searchequality

Computer diagnostics, which everyone is now used to, is absolutely useless when it comes to older cars. Fortunately, the diagnostics of the VW Passat B3 single injection is not a task that requires special education. Troubleshooting a single-injection Volkswagen Passat b3 is within the power of any competent owner.

Disassembled mono-injector

One of the common malfunctions of the Volkswagen Passat b3 mono-injection is a violation of the tightness of the gasket, in which the distribution of fuel becomes uneven. Such a breakdown is cured very simply - by replacing the gasket. Other frequent malfunction- violation of the connection of the wires located under the yellow sensor on a single injection. The sensor can be easily removed for diagnostics. Do not forget about the rest of the wires - checking their integrity can solve the problem.

Cleaning the single-injection Passat b3 will help you cope if carbon deposits have formed on the throttle or it is clogged. The question: “how to clean the Passat B3 single injection?” Has a very simple answer - disassemble and clean it. Fortunately, this unit has a fairly simple design and is easy to maintain.

The cover of the distributor can cause inconvenience even if the penetration is indistinguishable to the eye. In this case, only a replacement will help. Replacement will help with clogging fuel filter- a common cause of problems. The fuel cell may also need to be replaced, as a failure could result in improper compression.

Of course, this is far from complete list possible faults, but it is better to entrust the solution of other reasons to car service specialists. If the above tips helped, then the second stage of work is ahead - setting up.

Single injection setting

The first step is to measure the resistance value of the air supply temperature sensor to the single injection using a multimeter. The resistance value should be approximately 1800-1900 ohms at an air temperature of 20 degrees Celsius. For a working sensor, heating will lead to a decrease in resistance, and cooling will lead to an increase. The injector resistance should be in the range of 1200-1600 ohms.

Sensor Diagnostics

Next, you need to adjust the idle clearance. Throwing 12 V on the contacts of the regulator, we put the accelerator in its extreme position. With a multimeter, we check for a short circuit by inserting the probe into the gap between the end switch of the aforementioned accelerator and the rod. With an excessive distance between the limit switch and the stem, the multimeter will not show the appearance of a short circuit. The gap can be adjusted by changing the screw located at the bottom of the single injection, the location of the limit switch.

The next step is to set the throttle. This action is performed after the installation of a single injection on the engine with the connection of the injector connectors and sensors. It is also necessary to connect the fuel supply. After completing all the above actions disconnect the battery and turn on the ignition. This action will reset the mono injection settings.

Installation

Having connected the battery back, we check the voltage between pins 1 and 5 on the connector that controls the throttle. You should get a result of 5-6 volts. Measurement between the first and second contacts should give a result of 0.186 volts. For other values, adjustments must be made. With a multimeter connected to the first and second contacts, it is necessary to turn the shutter cover to the side, after loosening the screws, fixing the voltage value and bringing it to the required one.

Actually, in such a simple way, the Volkswagen Passat b3 mono-injection is repaired. For him, the most basic knowledge in car repair and tools available in the garage of any car enthusiast, not to mention professionals, is enough. Following these tips will save you a lot of money in the future due to less frequent visits to the service station.

Video: Adjusting the relay and idle sensor, as well as setting up the Passat b3 single injection

Not all malfunctions can be detected using the method described above, and not all systems allow you to poll the memory at home. But it is possible to draw a conclusion about the cause of the defect by analyzing the external manifestations of malfunctions. Let's consider this using the example of the Mono-Jetronic and Digifant systems.

Table 3. Malfunctions of the Mono-Jetronic system

sign	Cause
A. Cold engine does not start or starts badly	1. F18 fuse blown 2. Faulty additional resistance Z. The fuel pump does not work 4. Defective fuel pressure regulator 5. Defective coolant temperature sensor 6. Defective throttle potentiometer 7. Faulty control unit 8. Malfunctions in the wiring harness from the Hall sensor 9. Air suction
B. Warm engine does not start or starts poorly	1. see paragraphs. A2-9 2. Nozzle leakage
B. Engine stalls after starting	1. Throttle positioner does not work 2. see item A6 3. Lambda probe defect
D. Cold engine vibrates at idle	1. see item A5 2. see point B1
	See point B1
	See point B1
	1. clogged fuel filter 2. see item A3 3. see item B2 4. see point B3
Z. Unstable rpm crankshaft of the engine in the range of 2000 - 3000 min-1	See A6
I. Engine vibrates, runs rough	See p. A6
K. Insufficient power	1. see paragraphs. A3, A6, A9 2. see point B3 3. Throttle not set to "full throttle" position
L. Pops in the intake manifold	1. see p. A4 2. see item B3
	1. see paragraphs. A5, A6, A9 2. see item B3

Table 4. Malfunctions of the "Digifant" system

sign	Cause
A. Cold engine does not start or starts poorly	1.Fuse F18 blown 2. No voltage on relay K12 3. The fuel pump does not work 4. Leaky cold start valve or it does not inject 5.Defective fuel pressure regulator 6. Defective coolant temperature sensor 7.Defective throttle potentiometer 8.Defective control unit 9. Defect in the wiring harness from the Hall sensor 10. Air suction
B. Warm engine does not start or starts poorly	1. Defective vacuum hose connected to the fuel pressure regulator 2. See paragraphs. A2-10 3. The fuel injection pump does not work after turning off the engine 4.Leakage in the nozzle
Q. Engine starts but stalls again	1. The idle speed stabilization valve does not work 2.See pp. A 6 and A 7 3.See item B 1 4. Faulty CO potentiometer 5. Defect of the air quantity sensor or wires to it 6.Defective switch on the throttle shaft
D. Cold engine vibrates when idling	1.See item A 6 2.See p. B 1 3. Mismatched operation of the control unit and throttle potentiometer
E. Warm engine vibrates at idle	See paragraphs. B1 and B 4
E. Idle speed drops when steering wheel is turned all the way	See point B 1
G. Engine runs rough	1. Clogged fuel filter 2. See item A 3 H. See item B 4 4. See paragraphs. B 4 and B 5
Z. Unstable revolutions of the crankshaft of the engine in the range of 2000-3000 min-1	1. See point A 7 2. See point B 6
I. Engine vibrates, stalls	See point A 3
K. The engine does not develop power	1. See paragraphs. A 3, A 7 and A 10 2. See paragraphs. At 4, At 6 H. Knock sensor defect 4. Throttle does not open fully
L. Popping in the intake manifold	1. See item A5 2. See point B 4
M. Increased consumption fuel	1. See paragraphs. A 6 and A7 2. See point B 4

A common problem for a common German car: how to set up and repair a single injection on a Volkswagen Passat B3. This model is very common of all model range Volkswagen.

It is characterized by the following positive traits: reliability, spaciousness, durability, ease of maintenance. In general, this car contains many characteristics that make it a truly popular car. It can also be noted that the interior is large and spacious, the car starts at very low temperatures, the body is made with high quality, for his age a very high-spirited car.

Thanks to these advantages many people use the Passat B3 as a workhorse, it can be found everywhere: in the city, in the country, in the middle of a field, in a forest, in swamps, while fishing. Although the car is very reliable, breakdowns and stability in the operation of the engine are also found in it. So, one of the problems can be, because of which the car starts to behave badly, as people say - the car "stupid".

Even if the car started up well, then after a while while driving, a drop in speed is possible and the gas pedal seems to sink. These problems are related to the engine's mono-injection.

Setting up and repairing a single injection on a Volkswagen Passat B3 is not a difficult task, the most important thing is to find the cause of this problem. Complexity computer diagnostics in this model is complicated by the lack of a computer connection module. The problem with uneven mono injection, as a rule, can be as follows:

• there is a gasket under the mono-injection, in case of violation of the tightness of which uneven distribution of fuel begins (replacement of the gasket);
• a yellow sensor is installed on the device itself, under which wires are hidden. It is necessary to remove the sensor and check the integrity of the wire connection;
• if the problem starts, return the old ones and check, as the malfunction may be related to them (selection of the optimal type of candles);
• a broken trampler cover is possible (it needs to be replaced here). The hole may be insignificant, not even visible to the naked eye;
• on the sensor that regulates the throttle position, the resistance should change without significant dips in values ​​(checking the integrity of the wiring);
• improper compression of the fuel pump (repair or replace fuel cell);
• (replacement with a new one);
• soot and throttle clogging (simple).

Above are the main problems playing important role in the operation of a single injection. If these troubleshooting options did not help, then you should consult with specialists. After the mono-injection has been repaired, it is also necessary to properly adjust it. Setting is carried out in the following order:

• you need to measure the resistance on the intake air temperature sensor with a multimeter and compare it with the table value (if work is carried out at room temperature 20-25 ° C, then the resistance value is at the level of 1.8-1.9 kOhm);
• when the intake air sensor is heated, the resistance drops; when cooled, it grows. If everything is exactly so, therefore, the sensor is working;
• we measure the resistance of the nozzle itself (resistance values ​​are in the range from 1.2 to 1.6 ohms). When obtaining values ​​above, check the error of the multimeter, it can be significant. This is described in more detail in the article "";
• then set the idle clearance of the single injection. By supplying a voltage of 12 V from the battery to the contacts of the regulator, we put the accelerator in its extreme position. We set the multimeter to the "short circuit" mode and connect the contacts to the accelerator controller. The following situation should turn out: there should be a gap between the rod and the accelerator limit switch, insert the probe into this gap (ideally 0.45-0.5 mm), if the multimeter does not register a short circuit, then the distance is too big. It should be noted that adjusting bolt with this procedure, it is necessary to set according to the instructions. So, if the gap is too big, then we adjust the position of the accelerator limit switch with a screw located at the bottom of the single injection;
• adjust the throttle position. To do this, you need to install a single injection on the engine and connect the connector to the nozzle, the throttle position sensor and the intake air sensor. We connect the fuel hoses and, and turn the ignition key. This resets all on-board device settings. After that, we connect the battery in place.

We measure the voltage on the first and fifth pins of the throttle connector (with the ignition on), there should be 5–6 V. Then, between pins 1 and 2, the value is 0.186 V, if not, then we adjust. To do this, loosen 4 screws of the damper cover, to contacts 1 and 2 and turn the cover in one or the other direction, while changing the voltage.

This completes the setup, we assemble the mono-injection to the end and start the car. Thus, the tuning and repair of the single injection on the Volkswagen Passat B3 is being carried out. If they are not afraid to smear their hands, and they grow from the right place, then there is nothing difficult about it. Doing everything yourself is much more pleasant than paying someone else a lot of money for it.

SERGEY SAMOKHIN, "ABS"

“Does not go! Or rather, it somehow rides, sometimes it doesn’t, sometimes it stalls at idle ... ”- the owner of the VW Passat B3, manufactured in 1991, shared his grief. Well, now we will see it (the car, of course), listen, smell it ...

"Trade winds" of the B3 series were equipped a wide range gasoline engines, starting from a four-cylinder, with a volume of 1.6 liters, to a V-shaped "six" with a volume of 2.8 liters. The engines were equipped with the same variety of fuel systems: Solex-Pierburg carburetor, single-point and port injection manufactured by Bosch or VW. What fate has in store for us this time?

Reflections at the open hood

Under the hood was a 2-liter, 16-valve model 9A engine with a Bosch KE-Motronic control system. According to diagnostic specialists, the engine is far from the most successful of the Volkswagen series. Did not cause delight and KE-injection. It's not that this system injection is bad, it's just that it has not been installed on cars for a long time. Quite often found here, in Russia, specimens have already practically exhausted their resource, especially since in our conditions, as at the front, one year goes by two, or even three.

New parts for the KE-Jetronic hydro-mechanical assembly are very expensive (a distributor head, for example, costs about 800 "green", and a fuel dispenser assembly costs twice as much). At the "showdown" - only trash of dubious quality, so the cost quality repair such systems can be comparable to the cost of a car. The client does not go for a full-fledged repair, so they usually limit themselves to half-measures that allow them to temporarily extend the life of the engine: they patched it up somewhere, tweaked it somewhere, somehow something works - and okay. With this approach, the repair cannot be completed, it can only be stopped!

However, let's not rush things, and therefore - "come to boxing!"

insidious pump

IN enclosed space diagnostic box, the walls of which are sheathed with a metal sheet, became especially clearly audible extraneous noise mixed with the sound of a running engine. It was not difficult to establish that their source is behind the right rear wheel. The gas pump worked unusually noisily, sometimes "bucking" like a hungry Carlson's motor.

Increased noise of work and from time to time changing tone is a direct sign indicating that not everything is in order with the fuel pump. But immediately sending the client for a new one is still premature. It is possible that this reason is not the main one, but just one of a number of unfortunate consequences.

To rule out the possibility of electrical faults, before checking fuel devices we carry out preventive measures: we make sure that the battery voltage is normal, and we power the pump directly from it.

It must be borne in mind that on this car two pumps are installed - the main one (roller type), mounted under fuel tank, and booster (turbine), placed directly in the tank. Such a two-pump scheme is not an integral feature of KE systems, it is sometimes used in devices purely electronic injection, for example on Volvo-240 cars.

The fact is that the roller pump has a low suction capacity and in some cases a turbine one is installed in front of it. IN last years this problem is solved by using pumping units in which both pumps are mounted in a single housing.

It is possible that the booster pump is also junk, although it is more reliable than the roller one, so we “throw” a couple of wires onto its terminals.

An experiment with a reliable redundant power supply showed that no fundamental changes occurred. The main pump was still strainingly buzzing, sometimes choking unpredictably. Periods of pump failures unequivocally reflected in the nature of the engine.

What's next? Further, as recommended, is the measurement of system pressure and performance. We connect a pressure gauge through the adapter to the power line of the starting injector, it will show the value of the system pressure. Immerse the undocked backflow pipe into a plastic container. We mark the time. Go!

Despite the short-term malfunction of the fuel pump noted by ear, the measurement of the amount of fuel is within the norm! This shows the insidiousness of roller pumps. Not always their performance degrades gradually. Sometimes there are short-term failures that are difficult to fix when determining the performance, which is measured within a minute.

However, the pressure gauge still responded to the failure, noting a drop in system pressure. For persuasiveness, we use additional method checks. Using the non-contact sensor of the oscilloscope, we measure the currents in the power circuits of both pumps.

The experiment shows that the current of the booster pump is stable, while the current of the main pump drops from 8 to 6A at the moments of engine failure, and the drop is accompanied by the appearance of ripples. This suggests that the load on the pumping unit of the pump is reduced due to leakage and fuel leaks.

For the final confirmation of the diagnosis, as well as to check other elements of the fuel system, we connect instead of regular pumps offline installation for cleaning injection systems, which incorporates a pump that develops the desired pressure. When the engine is running from the unit's pump, the system pressure stabilizes in the range corresponding to the passport value - from 6.1 to 6.6 bar, no dips are observed. This indicates that the mechanical pressure regulator is working. And how does his electro-hydraulic partner feel?

It is worth checking the correctness of its work. In the event of a fuel supply failure, if the car falls into the hands of unskilled repairmen, it is not uncommon for them to try to eliminate the manifestations of a malfunction by making adjustments, the meanings of which they do not fully understand, and therefore they do not experience fear of “cogs”.

A normally operating EHA must maintain a differential pressure (the difference between the system and pressure in the lower chamber of the fuel dispenser) in the range of 0.2 to 0.5 bar at stationary engine operation. Additionally, the control current is subject to verification. To do this, a milliammeter is connected to the break in the EHA control circuit.

For this engine in idling mode on a warm engine with lambda correction turned off, the current should be zero. This indicates the absence of ECU intervention in maintaining the composition of the mixture (basic fuel dosing is carried out). When a lambda sensor is connected, abrupt gas flow, full throttle opening, the control current is different from zero and changes in accordance with the program embedded in the computer.

The pressure measurement in the lower chamber of the dispenser showed that the differential pressure is within the norm (0.45 bar). This means that no one has yet reached the EHA fine-tuning screw. A different fate befell the mixture adjustment screw, which, unfortunately, is more accessible. I had to perform a gas analysis and adjust the mixture.

That, it would seem, is all. Now, after replacing the main fuel pump, the injection system should work as it should. It remains only for order to read the fault codes stored by the ECU and delete unnecessary information. It turned out that this order was not established in vain.

Tricky ring

The scanner, in addition to indicating several sporadic errors that do not affect the performance of engine systems, issued a message: 514 - Ignition timing sender - NO SIGNAL. If you “Russify” the message of the ECU, it means that the unit does not receive a signal from the sensor that registers the ignition moment in the fourth cylinder.

It has nothing to do with the injection system. The sensor is used to determine in which particular cylinder knock occurs, which is detected by the knock sensor. Information is needed by the control system to individually adjust the ignition timing for each engine cylinder. The absence of a signal does not lead to a loss of engine performance, but reduces its efficiency.

The sensor is a winding consisting of several turns of wire, enclosed in a plastic ring case, equipped with an electrical connector. The ring is put on the high-voltage wire of the fourth cylinder. When a spark discharge current passes through the wire, a voltage pulse is induced in the winding, which is recorded by the ECU.

The resistance of the sensor winding is very small; one “ring” is not enough to determine its performance. The output signal was checked with an oscilloscope. She showed that there is a signal, but its amplitude (25mV) is about 4-5 times less than normal. That is why the ECU does not “see” it and registers an error.

The reason turned out to be banal - the use of non-standard high-resistance wires. The resistance of the "native" should be about 2kOhm, while the used one should be 10-12kOhm. By the way, an incorrectly worn “ring” can lead to similar consequences. If you put it on a wire reverse side, the polarity of the signal will change and it will become invisible to the control unit. Be careful when changing wires!

That's all for now, and the final denouement will come when the owner of the Passat saves up 200 bucks to buy a new pump.