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4.22. Search of malfunctions of system of injection of fuel

System of injection of L-Jetronic fuel

Malfunction Possible reason Way of elimination
The engine (cold) is started hardly or not started The injector of cold start or the temperature switch is faulty Check an injector of cold start and the temperature switch. Replace faulty components (watch the Section Check of Functioning and Replacement of an Injector of Cold Start and the temperature switch)
The fuel pump does not work Check a safety lock of the fuel pump and relay of the fuel pump (look the Sections Check of Pressure of Fuel / Fuel of the pump and Removal and installation of the fuel pump, intermediate pump and fuel level sensor)
The petal (valve) of the measuring instrument of a stream of air jams or sticks in open situation Examine the air stream measuring instrument regarding damages (look the Section Functioning Check, removal and installation of the measuring instrument of a stream of air)
Wrong pressure of fuel Check pressure in system (watch the Section Check of Pressure of Fuel / Fuel of the pump). Check the regulator of pressure of fuel (Section Check of Functioning and Replacement of the Regulator of Pressure of Fuel)
Leak of inlet air Examine all vacuum lines, air ducts, epiploons of an oil filter and the masloizmeritelny probe
Fuel injectors are corked or do not work Check fuel injectors (watch the Section Check of Functioning and Replacement of Fuel Injectors) and a cable
The sensor of temperature of a cooler or problem with wires is faulty Check the cooler temperature sensor (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases, the Section Check of Pressure of Fuel / Fuel of the pump)
The sensor of provision of a throttle (TPS) is incorrectly adjusted Check TPS adjustment (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases, Undressed Information sensors)
Wrong moment of ignition Check the ignition moment (watch the Head Sistem of ignition). Check the vacuum proofreader of ignition
Dirt or other inclusions in fuel Check fuel and, if necessary, merge fuel from a tank
ECU is faulty Check ECU at the dealer or other expert
The engine (heated-up) is started hardly or not started Leak in an injector of cold start or constantly open state Check an injector of cold start and the temperature switch (watch the Section Check of Functioning and Replacement of an Injector of Cold Start and the temperature switch)
Wrong pressure of fuel Check the fuel pump(s). If necessary replace (watch the Section Check of Pressure of Fuel / Fuel of the pump)
Insignificant residual pressure of fuel Check the residual pressure of fuel. Replace if necessary the fuel pump or the fuel accumulator (watch the Section Check of Functioning and Replacement of the Regulator of Pressure of Fuel)
Leak (utesk) of fuel Examine fuel lines and fuel injectors regarding leaks. Eliminate leaks as it is specified (watch Chapter the Power supply system)
The sensor of temperature of a cooler or problem with wires is faulty Check the cooler temperature sensor (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases, Undressed Information sensors)
Gas stopper in a fuel-supply line (hot weather) Check fuel pressure (watch the Section Check of Pressure of Fuel / Fuel of the pump)
Malfunction of the EVAP system (if it is applied) Check the EVAP system (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases, the Section System of Catching of Vapours of Gasoline (EVAP))
Wrong moment of ignition Check the ignition moment (watch the Head Sistem of ignition). Check the vacuum regulator of ignition
ECU is faulty Check ECU at the dealer or other expert
Malfunction of the control system of idling Check the air valve of stabilization of idling (look the Section Functioning Check, adjustment and replacement of the air valve of stabilization of idling)
The engine under loading glitches and twitches The fuel injector is corked or faulty Check fuel injectors. Check existence of the corked fuel lines. Replace faulty injectors (watch the Section Check of Functioning and Replacement of Fuel Injectors)
Wrong pressure of fuel Check pressure in fuel system (watch the Section Check of Pressure of Fuel / Fuel of the pump). Check the fuel pressure regulator (watch the Section Check of Functioning and Replacement of the Regulator of Pressure of Fuel)
Leak (leaks) of fuel Check existence of leaks in fuel lines and fuel injectors (watch Chapter the Power supply system)
Service of the engine Adjust the engine (watch Chapter Routine maintenance of the car). Check an ignition distributor cover, the runner, high-voltage wires and spark plugs and replace any faulty components
The petal (valve) of the measuring instrument of a stream of air jams or sticks in open situation Examine the air stream measuring instrument regarding damage (look the Section Functioning Check, removal and installation of the measuring instrument of a stream of air)
Leak of inlet air Examine all vacuum lines, air ducts, epiploons of an oil filter and the masloizmeritelny probe
The engine has unstable turns of idling The air valve of stabilization of idling is faulty Check the air valve of stabilization of idling (look the Section Functioning Check, adjustment and replacement of the air valve of stabilization of idling)
There is no power supply of the valve of stabilization of idling Check the relay of the stabilizer of idling and a wire (watch the Head Sistem of onboard electric equipment)
The vacuum regulator of ignition is faulty Check the vacuum regulator of ignition and the electronic relay of the vacuum regulator of ignition
The idling control block is faulty Check the idling control block at the dealer

Fuel system of injection Motronic

In this system in case of refusal ECU stores a malfunction code in memory. These codes can be read only at the dealer of BMW as the special equipment is required. If the dealer executes, at least, initial diagnostics of malfunctions, then it will allow to save time.


Malfunction Possible reason Way of elimination
Loss of power The sensor of temperature of a cooler or break of a wire to the sensor is faulty Check the sensor of temperature of a cooler and a wire. Correct a wire or replace the sensor if it is faulty (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases)
Wrong pressure of fuel Check fuel pressure in the fuel pump and the intermediate pump if it is applied (watch the Section Check of Pressure of Fuel / Fuel of the pump)
The valve of a throttle opens not completely Check adjustment of a cable of an accelerator to be convinced of full opening of the valve of a throttle.
Adjust a cable if it is necessary (look the Section Check, adjustment and replacement of a cable of an accelerator)
The engine (cold) is started hardly or not started The injector of cold start or the temperature switch is faulty (only on the early Motronic systems) Check an injector of cold start and the temperature switch. Replace faulty components (watch the Section Check of Functioning and Replacement of an Injector of Cold Start and the temperature switch)
The fuel pump does not work Check a safety lock and the relay of the fuel pump (watch the Section Removal of Pressure in system of injection of fuel and Check of pressure of fuel / the fuel pump)
The petal (valve) of the measuring instrument of a stream of air jams or sticks in open situation Examine the air stream measuring instrument regarding damage (look the Section Functioning Check, removal and installation of the measuring instrument of a stream of air)
Wrong pressure of fuel Check pressure in system (watch the Section Check of Pressure of Fuel / Fuel of the pump)
Leak of inlet air Examine all vacuum lines, air ducts, epiploons of an oil filter and the masloizmeritelny probe
Fuel injectors are corked or do not work Check fuel injectors (watch the Section Check of Functioning and Replacement of Fuel Injectors) and a cable
The sensor of temperature of a cooler or problem with wires is faulty Check the cooler temperature sensor (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases, Undressed Information sensors)
TPS (the sensor of provision of a throttle) is incorrectly adjusted Check TPS adjustment (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases, Undressed Information sensors)
Dirt or other inclusions in fuel Check fuel and, if necessary, merge it from a tank
ECU is faulty Check ECU at the dealer or other expert
The signal of provision of a bent shaft vanishes The sensor of situation or flywheel is faulty, or the reperny pin is not lost
The engine (heated-up) is started hardly or not started The injector of cold start proceeds or is constantly open (only on the early Motronic systems) Check an injector of cold start and the temperature switch (watch the Section Check of Functioning and Replacement of an Injector of Cold Start and the temperature switch)
Wrong pressure of fuel Check fuel pressure (watch the Section Check of Pressure of Fuel / Fuel of the pump)
Insignificant residual pressure of fuel Check the residual pressure of fuel system (watch the Section Check of Pressure of Fuel / Fuel of the pump)
Leak (and) fuels Examine fuel lines and injectors regarding leaks. If necessary, eliminate leaks
The sensor of temperature of a cooler or problem with wires is faulty Check the cooler temperature sensor (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases, Undressed Information sensors)
Gas stopper in a fuel pipe (hot weather) Check fuel pressure (watch the Section Check of Pressure of Fuel / Fuel of the pump)
The EVAP system is faulty Check the EVAP system (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases, the Section System of Catching of Vapours of Gasoline (EVAP))
The idling control system is faulty Check ECU at the dealer or other expert
The oxygen sensor is faulty (where it is applied) Check the air valve of stabilization of idling (look the Section Functioning Check, adjustment and replacement of the air valve of stabilization of idling)
Check the oxygen sensor (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases, Undressed Information sensors)
The engine under loading glitches and twitches The fuel injector is corked Check fuel injectors. Check passability of lines of injectors. Replace faulty injectors (watch the Section Check of Functioning and Replacement of Fuel Injectors)
Wrong pressure of fuel Check pressure of fuel system (watch the Section Check of Pressure of Fuel / Fuel of the pump). Check the fuel pressure regulator (watch the Section Check of Functioning and Replacement of the Regulator of Pressure of Fuel)
Leak (and) fuels Check fuel lines and injectors for existence of leaks (watch Chapter the Power supply system)
Service of the engine Adjust the engine (watch Chapter Routine maintenance of the car). Check a distributor cover, the runner, high-voltage wires and spark plugs and replace all faulty components
The petal (valve) of the measuring instrument of a stream of air jams or sticks in open situation Examine on existence of damage of the measuring instrument of a stream of air (look the Section Functioning Check, removal and installation of the measuring instrument of a stream of air)
Leak of inlet air Examine all vacuum lines, air ducts, epiploons of an oil filter and the masloizmeritelny probe
The sensor of provision of a throttle (TPS) is incorrectly adjusted Check TPS adjustment (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases)
The raised turns of idling of the engine Jams an accelerator pedal, a cable or the valve of a throttle Check existence of the worn-out or broken components, the overwound cable or other damages. Replace faulty components
Leak of air in the throttle valve Examine the valve of a throttle and adjust or, if necessary, replace
Unstable turns of idling of the engine The air valve of stabilization of idling is faulty Check the air valve of stabilization of idling (look the Section Functioning Check, adjustment and replacement of the air valve of stabilization of idling)
There is no power supply of the valve of stabilization of idling Check the relay of the stabilizer of idling and a wire (watch the Head Sistem of onboard electric equipment)
The idling control block is faulty Check the idling control block at the dealer
The increased fuel consumption The injector of cold start (only early Motronic systems) proceeds Check and, if necessary, replace an injector of cold start (watch the Section Check of Functioning and Replacement of an Injector of Cold Start and the temperature switch)
The oxygen sensor is faulty (where it is applied) Check the oxygen sensor (watch Chapter of the Control system of the engine and decrease in toxicity of the fulfilled gases, Undressed Information sensors)
Jams a parking brake / brakes brake Check a parking brake / brake systems (watch Chapter the Brake system)
Low pressure in tires Check pressure in tires