BMW 3 series E30

Since 1983-1994 of release

Repair and car operation

+ 1. The maintenance instruction
+ 2. Maintenance service
+ 3. The engine
+ 4. Cooling system
+ 5. Heating and ventilation
+ 6. Fuel system
- 7. An exhaust system
   + 7.1.2. An exhaust system of cars 318i
   - 7.2. System of decrease in toxicity of the fulfilled gases
      7.2.2. Self-diagnostics of system of injection Motronic
      7.2.3. The processor block (block ESU)
      7.2.4. Gauges of system of automatic control of the engine
      7.2.5. System of compulsory ventilation картера (PCV-system)
      7.2.6. System of catching of steams of gasoline (EVAP-system)
      7.2.7. Katalitichesky neutralizer
+ 8. Transmissions
+ 9. Coupling
+ 10. Brake system
+ 11. A running gear
+ 12. A body
+ 13. An electric equipment
+ 14. A good advice

7.2.4. Gauges of system of automatic control of the engine

The gauge of temperature of a cooling liquid

The gauge of temperature of a cooling liquid (marksman), pressure from which moves on the processor block, is located near to the gauge of the index of temperature, about a regulator of pressure of fuel.

The gauge represents термистор (the resistor which size of resistance depends on temperature). In process of reduction of temperature of the gauge its resistance increases and on the contrary.


1. For gauge check, disconnect a socket and measure resistance of the gauge. On the cold engine resistance should be from 2 to 3 clod. Start the engine and warm up – resistance of the gauge should become 200–400 Ohm.

The prevention

If access to the gauge is complicated, remove the gauge and measure resistance, having placed it in a vessel with нагретой water.

2. To remove the gauge, wring out latches, disconnect a socket and accurately turn out the gauge. It is recommended to merge at first from system of cooling of a few liquid.
3. Installation is carried out upside-down. Slightly grease a carving of the gauge with hermetic.

The gauge of concentration of oxygen in exhaust gases

The gauge of oxygen of oxygen is established in cars with каталитическим neutralizer. The gauge will screw in a forward exhaust pipe after a final collector.

Socket of the gauge of oxygen
The socket of the gauge of oxygen on models 318i the beginnings of 1984 is located on the left side of the battery. On models of second half 1984 and 1985 the gauge settles down in the same place.

Socket of the gauge of oxygen on models 325i 1986-88

The gauge traces the oxygen maintenance in exhaust gases and generates target pressure from 0,1 In (the high maintenance of the oxygen, the impoverished mix) to 0,9 In (the small maintenance of the oxygen, the enriched mix). Changing target pressure from gauges moves on the electronic block of management which defines an oxygen and fuel parity in a gas mixture. The management block regulates a parity of air / of fuel in a mix by the task of time of an open condition of atomizers. At a parity of 14,7 parts of air to 1 part of fuel in an initial mix the maintenance of harmful substances in the fulfilled gases minimum, at such parity neutralizer clears gases with peak efficiency. The electronic block of management together with the oxygen gauge provide maintenance of structure of a gas mixture just at the specified level.

The relay of a heater of the gauge of oxygen

If temperature of the gauge of concentration of oxygen below normal working temperature, i.e. 320 With pressure on the gauge is absent. Therefore, until then while the engine will not get warm, on the electronic block of management of a signal from the oxygen gauge the block does not arrive also works in a mode of the opened cycle (preparing a gas mixture automatically).

If after engine warming up, or after not less than 2 minutes of work of the engine, pressure on the gauge not превышаеи 0,45 In at speed of rotation of the engine not less than 1500 rpm the management block will bring a refusal code in memory.

If the gauge or its chain the electronic block of management works in a mode of the opened cycle are faulty, i.e. The block doses out fuel according to the programmed value on its input, instead of according to a signal of the gauge of oxygen.

Correct work of the gauge depends on following conditions:

1. Electric: the low voltage generated by the gauge, very strongly depends on a condition of connections with wires.

2. Givings of external air: the gauge is arranged so that air circulates in its internal space. Every time at removal or installation be convinced of cleanliness of air channels of the gauge.

3. Working temperature: signals from the gauge do not arrive on the electronic block of management until then while the temperature of the gauge will not reach approximately 300 S.Etot the factor it is necessary to consider at an estimation of serviceability of the gauge.

4. Qualities of gasoline: use неэтилированного gasoline is an essential condition of correct work of the gauge. Fill the car only неэтилированным with gasoline.

Besides specified above conditions, at gauge service it is necessary to observe following rules:

1. The flexible conductor and a socket of the gauge of oxygen are not folding and from the gauge are not disconnected. Damage or a separation of a flexible conductor or a socket can negatively affect serviceability of the gauge.

2. It is not supposed hits of a dirt, lubricants and other extraneous components on a socket or on a tower insulator of the gauge.

3. It is forbidden to wipe the gauge all kinds of cleaners.

4. It is forbidden to drop the gauge or carelessly to address with it.

5. Watch correctness of installation of a silicone cover of the gauge to avoid cover fusion because of which gauge refusal is possible.

Types of the sockets applied to connection with the gauge of the maintenance of oxygen and a designation of conclusions (from outside conductings)

Appointment of conclusions to the gauge of the maintenance of oxygen

Without heating (single-wire)
Black wire (+)
Warmed up (3-wire)
Conclusion 1 (+)
Conclusions 3 (+) and 2 (+)
Warmed up (4-wire)
Conclusion 2 (+)
Conclusions 4 (+) and 3 (-)


1. Warm up the engine, disconnect a socket and check up the digital voltmeter pressure on a conclusion of a target signal of the gauge concerning weight. The gauge find on the big cover with a plait of black colour in a back part of the engine.
2. At increase in turns pressure from the oxygen gauge should increase from 0,5 to 1,0. At reduction of turns pressure decreases to 0–0,4 V.Esli a signal from the oxygen gauge differs from the specified values the gauge replace.
3. Check up a heater of the gauge of oxygen (on a part of cars). On the specified conclusions there should be a pressure 12 V.Pri absence of a food check up the gauge relay.


The prevention

At cooling the final collector or an exhaust pipe in which will screw the gauge, are compressed, therefore, on the cold engine to turn on the gauge difficultly. Not to damage the gauge (it is supposed that you will use it further) start and warm up the engine within 1–2 minutes, stop the engine.

1. Disconnect the battery from weight.
2. Lift the car and establish on supports.
3. Accurately disconnect a socket from gauge conducting.
4. Cautiously turn out the gauge.
5. At installation grease a carving of the gauge with structure against прихвата.

The gauge represents 2 steams of contacts. Idling which one steam it is normally closed, and another – is opened. Near to full opening заслонки the second pair of contacts becomes isolated. At intermediate position заслонки both steams of contacts are opened. Breakage in chains or easing of contacts of the gauge throttle заслонки can cause spontaneous injection of fuel that is at the bottom of unstable work of the engine idling.


1. The gauge of turn throttle заслонки settles down at an end face of a shaft throttle заслонки. Disconnect a socket and check up resistance between steams conclusions 2–18 and 3–18.
2. Between conclusions 2–18 should be a chain before assignment заслонки on 0,2–0,6 mm from the closed position.
3. Between conclusions 3–18 should be a chain which remains at opening заслонки to at 8-12 rather completely open position. If check yields negative result adjust the gauge.
4. If заслонка it is adjusted, check up pressure of a food 5 In on the gauge.


Release screws and having turned, establish the gauge in the necessary position, tighten screws and check up adjustment.

Measuring instrument of a stream of air

The removal and installation order is described in subsection 6.4.

Gauges of system of ignition

The procedure for test, removals and installations is described in subsection