How to Deal With the Problem of Difficult Starting of BMW 318i

 How to deal with the problem of difficult starting of BMW 318i 

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 (1) Fault symptoms The chassis model of this car is E46, equipped with an N46 engine. The fault 

symptoms are as follows: After parking the vehicle for a long time, the starter needs to be started more 

than twice before the engine can run. If it starts immediately after turning off the engine, start the 

engine once and you can start the car. 

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 (2) Diagnosis and maintenance: Confirm the fault symptoms. After parking the vehicle for 10 minutes, 

start the engine. The engine can start, but the speed drops rapidly and stalls after starting. Then it 

started 

again and the engine finally started running. Use the diagnostic tool to conduct self-diagnosis and check 

the fault information of the engine system. There is no fault code. Checked the fuel pressure, ignition 

strength and intake manifold sealing, and found no abnormalities. Measure the cylinder pressure and 

find that the pressure in each cylinder is normal. Looking at the engine's operating data, the intake 

valve 

lift is 9.58mm, which is close to the maximum value of the control volume. At this time, the intake 

manifold pressure is 53kPa, which is significantly lower than the atmospheric pressure of 100kPa, 

indicating that the electronic throttle valve has implemented throttling control and the engine system 

has activated emergency mode. The engine is equipped with an electronic valve control system. Under 

normal circumstances, the cylinder air intake volume is controlled by adjusting the intake valve lift, 

rather than by the electronic throttle. The electronic throttle is only used during starting conditions and 

emergencies. It plays a throttling role in mode. Therefore, when the engine is running, the intake 

manifold pressure should be the same as atmospheric pressure. The reasons that cause the engine 

system to activate emergency mode are as follows. Turn off the ignition switch and turn it on after 10 

minutes. Observe the engine's working data. The intake valve lift is 1.48mm and the throttle valve 

opening is 18%. This is normal. When the engine is started, the intake valve lift drops rapidly from the 

original 1.48mm to 0.30mm. At this time, the engine shakes violently until it stalls. When the engine is 

started again, the intake valve lift quickly drops from the original 1.48mm to 0.30mm, and then rises to

 9.58mm, and the engine starts running. The throttle opening is reduced from 18% to 3%, and the 

engine system enters emergency mode. The 0.30mm intake valve lift is not enough to get the engine 

started. Analyzing the reasons, if there is too much carbon deposit on the intake valve, the valve 

operation will be affected, making it difficult to achieve the predetermined lift, and the engine will stall 

due to too little air intake. In order to verify this inference, the learning value of the engine control 

module is cleared, and then the engine is started, and the intake valve lift is reduced from 1.48mm to

  0.62mm and remains unchanged, and the idle speed remains stable, indicating that the previous 

inference is correct. Keep engine speed at 2500r/min, use carbon removal agent to clean the air intake 

system. After completion, initialize the electronic valve control system and test drive. The fault 

symptoms disappear and the maintenance work is completed. 

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 (3) Summary: There is too much carbon deposit on the back of the intake valve, which causes the 

intake valve lift to be blocked and the engine stalls when it is first started. Afterwards, in order to 

enable the engine to start successfully, the engine control module enabled the emergency mode and 

used the electronic throttle to control the air intake volume instead of controlling the air intake volume 

 

through the intake valve lift. Therefore, the engine was able to run after two starts. During 

maintenance, 

pay attention to the engine's air intake control method, analyze the cause by viewing the data flow, and

 find the fault point.

How to Solve the Problem of BMW 318i Having Difficulty Starting

 How to solve the problem of BMW 318i having difficulty starting 

 (1) Fault symptoms The chassis model of this car is E46, equipped with an N46 engine. The fault 

symptoms are as follows: After parking the vehicle for a long time, the starter needs to be started more 

than twice before the engine can run. If it starts immediately after turning off the engine, start the 

engine once and you can start the car.

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 (2) Diagnosis and maintenance: Confirm the fault symptoms. After parking the vehicle for 10 minutes, 

start the engine. The engine can start, but the speed drops rapidly and stalls after starting. Then it 

started 

again and the engine finally started running. Use the diagnostic tool to conduct self-diagnosis and check

 the fault information of the engine system. There is no fault code. Checked the fuel pressure, ignition 

strength and intake manifold sealing, and found no abnormalities. Measure the cylinder pressure and 

find that the pressure in each cylinder is normal. Looking at the engine's operating data, the intake 

valve 

lift is 9.58mm, which is close to the maximum value of the control volume. At this time, the intake 

manifold pressure is 53kPa, which is significantly lower than the atmospheric pressure of 100kPa, 

indicating that the electronic throttle valve has implemented throttling control and the engine system 

has activated emergency mode. The engine is equipped with an electronic valve control system. Under

 normal circumstances, the cylinder air intake volume is controlled by adjusting the intake valve lift, 

rather than by the electronic throttle. The electronic throttle is only used during starting conditions and 

emergencies. It plays a throttling role in mode. Therefore, when the engine is running, the intake 

manifold pressure should be the same as atmospheric pressure. The reasons that cause the engine 

system to activate emergency mode are as follows. Turn off the ignition switch and turn it on after 10 

minutes. Observe the engine's working data. The intake valve lift is 1.48mm and the throttle valve 

opening is 18%. This is normal. When the engine is started, the intake valve lift drops rapidly from the 

original 1.48mm to 0.30mm. At this time, the engine shakes violently until it stalls. When the engine is 

started again, the intake valve lift quickly drops from the original 1.48mm to 0.30mm, and then rises to 

9.58mm, and the engine starts running. The throttle opening is reduced from 18% to 3%, and the 

engine 

system enters emergency mode. The intake valve lift of 0.30mm is not enough to start the engine.

  Analyzing the reasons, if there is too much carbon deposit on the intake valve, the valve operation 

will 

be affected, making it difficult to achieve the predetermined lift, and the engine will stall due to too 

little air intake. In order to verify this inference, the learning value of the engine control module is 

cleared, and then the engine is started, and the intake valve lift is reduced from 1.48mm to 0.62mm and 

remains unchanged, and the idle speed remains stable, indicating that the previous inference is correct.

  Keep the engine speed at 2500r/min and use carbon remover to clean the air intake system. After 

completion, initialize the electronic valve control system and test drive. The fault symptoms disappear

 and the maintenance work is completed. 

 

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 (3) Summary: There is too much carbon deposit on the back of the intake valve, which causes the 

intake valve lift to be blocked and the engine stalls when it is first started. Afterwards, in order to 

enable the engine to start successfully, the engine control module enabled the emergency mode and 

used the electronic throttle to control the air intake volume instead of controlling the air intake volume 

through the intake valve lift. Therefore, the engine was able to run after two starts. During maintenance,

 pay attention to the engine's air intake control method, analyze the cause by viewing the data flow, and 

find the fault point.

How to solve the problem of difficulty starting in BMW 318i

 How to solve the problem of difficulty starting in BMW 318i 

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 (1) Fault symptoms The chassis model of this car is E46, equipped with an N46 engine. The fault 

symptoms are as follows: After parking the vehicle for a long time, the starter needs to be started more 

than twice before the engine can run. If it starts immediately after turning off the engine, start the 

engine once and you can start the car. 

 BMW E-Sys Scripts Collection for New Features

 (2) Diagnosis and maintenance: Confirm the fault symptoms, park the vehicle for 10 minutes, and then

 start the engine. The engine can start, but the speed drops rapidly and stalls after starting. Then it 

started 

again and the engine finally started running. Use the diagnostic tool to conduct self-diagnosis and 

check 

the fault information of the engine system. There is no fault code. Checked the fuel pressure, ignition 

strength and intake manifold sealing, and found no abnormalities. Measure the cylinder pressure and 

find that the pressure in each cylinder is normal. Looking at the engine's operating data, the intake valve

 lift is 9.58mm, which is close to the maximum value of the control volume. At this time, the intake 

manifold pressure is 53kPa, which is significantly lower than the atmospheric pressure of 100kPa, 

indicating that the electronic throttle valve has implemented throttling control and the engine system 

has activated emergency mode. The engine is equipped with an electronic valve control system. Under

 normal circumstances, the cylinder air intake volume is controlled by adjusting the intake valve lift, 

rather than by the electronic throttle. The electronic throttle is only used during starting conditions and 

emergencies. It plays a throttling role in mode. Therefore, when the engine is running, the intake 

manifold pressure should be the same as atmospheric pressure. The reasons that cause the engine 

system to activate emergency mode are as follows. Turn off the ignition switch and turn it on after 10 

minutes. Observe the engine's working data. The intake valve lift is 1.48mm and the throttle valve 

opening is 18%. This is normal. When the engine is started, the intake valve lift drops rapidly from the 

original 1.48mm to 0.30mm. At this time, the engine shakes violently until it stalls. When the engine is 

started again, the intake valve lift quickly drops from the original 1.48mm to 0.30mm, and then rises to 

9.58mm, and the engine starts running. The throttle opening is reduced from 18% to 3%, and the 

engine 

system enters emergency mode. The 0.30mm intake valve lift is not enough to get the engine started.

  Analyzing the reasons, if there is too much carbon deposit on the intake valve, the valve operation 

will 

be affected, making it difficult to achieve the predetermined lift, and the engine will stall due to too 

little air intake. In order to verify this inference, the learning value of the engine control module is 

cleared, and then the engine is started, and the intake valve lift is reduced from 1.48mm to 0.62mm and 

remains unchanged, and the idle speed remains stable, indicating that the previous inference is correct.

  Keep engine speed at 2500r/min, use carbon remover to clean the air intake system. After completion,

 initialize the electronic valve control system and test drive. The fault symptoms disappear and the 

maintenance work is completed.

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  (3) Summary: There is too much carbon deposit on the back of the intake valve, which causes the 

intake valve lift to be blocked and the engine stalls when it is first started. Afterwards, in order to 

enable the engine to start successfully, the engine control module enabled the emergency mode and 

used the electronic throttle to control the air intake volume instead of controlling the air intake volume 

through the intake valve lift. Therefore, the engine was able to run after two starts. During maintenance,

 pay attention to the engine's air intake control method, analyze the cause by viewing the data flow, and 

find the fault point.

How to Solve the Problem of BMW not Starting

 How to solve the problem of BMW 318i not starting  

 (1) Fault symptoms: The chassis model of this car is E46, equipped with an M43 engine. The fault 

symptoms are as follows: when the engine is started, there is no sign of the engine starting, and the fuel 

gauge on the instrument panel indicates zero. 

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  (2) Diagnosis and maintenance. Remove the rear seat and the two flanges on the upper part of the fuel 

tank. It is found that there is no fuel in the right oil storage chamber, but the left oil storage chamber is full 

of fuel. This condition is usually caused by a damaged siphon mechanism inside the fuel tank. Taking 

out the siphon device, it can be seen that it is a simple siphon device with only a siphon pump and a 

connecting tube. After careful inspection, it was confirmed that there was no problem with the siphon 

device. Analyzing the cause of the failure, it may be insufficient fuel return pressure. After replacing 

the fuel filter and fuel pump, test drive and completely eliminate the fault.  

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(3) Summary The fuel pump is installed in the oil storage chamber on the left side of the fuel tank.

  During engine operation, excess fuel returns to the left oil storage chamber of the fuel tank, and is 

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pumped to the right oil storage chamber through the siphon device for recycling. Fuel requires a certain 

initial pressure when it returns, and the pressure comes from the fuel pump. Therefore, if the fuel pump 

performs poorly or the fuel filter is clogged, a fault like this will occur.

 

How to Solve the Problem of BMW Stalling After Starting

how to solve the problem of BMW 318i stalling after starting

 

  (1) Fault symptoms The chassis model of this car is E46, equipped with an M43 engine. The fault 

symptoms are as follows: After starting the engine, the engine shakes seriously and cannot keep 

running.

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  (2) Diagnosis and maintenance: Connect the diagnostic instrument for self-diagnosis. The engine 

system has multiple fault codes, but the information of these fault codes is not directly related to the 

fault symptoms. Cleared the fault code and tried driving, but the fault persisted. Query the fault 

information again and there is no fault code. Removed the spark plug and found that there was a lot of 

carbon deposits on the electrode. Replaced 4 spark plugs, problem still persists. Measure the fuel 

pressure and it can reach 380kPa at startup, which is normal. Unplug the wiring harness plug of the 

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injector and connect the test light. The test light flashes when starting, indicating that the control The 

line is good. After removing the four fuel injectors, it was found that they were all seriously clogged 

and had cotton-like debris inside. Remove the fuel filter and find that the internal filter element has 

been broken, indicating that the cotton-like debris is formed by the broken paper filter element. After 

replacing the fuel filter, cleaning the fuel lines and injectors, and testing the car, the fault was alleviated.

 However, as the engine temperature increased, the jitter symptoms became more and more serious, 

and 

the three-way catalytic converter burned dark red. After replacing 4 injectors, the engine would not 

start. The cylinder pressure was measured and the results showed that the cylinder pressure of 2 

cylinders was seriously insufficient. Remove the cylinder head, remove carbon deposits, grind the 

valves, reassemble and test run to completely eliminate the fault. 

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 (3) Summary: The car has been driving at low speed in the city for a long time, and the engine cannot 

reach the self-cleaning temperature, forming a large amount of carbon deposits. In addition, the fuel 

filter is not replaced regularly, the filter element is broken, causing pipeline pollution, and the fuel 

injector is scrapped. This illustrates the importance of proper vehicle use and regular maintenance.

How to Solve the Problem of BMW 318i Coolant level Warning light Coming On

(1) Fault symptoms The chassis model of this car is E46, equipped with an M43 engine. The fault 

symptoms are as follows: According to the owner, after starting the engine, the coolant level warning 

light (yellow water tank-shaped symbol warning light) on the instrument panel keeps lighting up. 

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(2) Diagnosis and maintenance: Start the engine and conduct actual inspection. No yellow water tank 

symbol warning light is found to be on. Turn off the ignition switch, and after the temperature drops, 

open the coolant reservoir cap. You can see that the liquid level is indeed low. Check the appearance of 

the engine and find no obvious signs of leakage. 

 

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       pressure test was conducted at the mouth of the liquid storage tank and no trace of leakage was found.

  No leakage when the engine is cold does not mean there is no leakage after the engine is running.

  There may also be internal leakage issues. Remove the spark plug and check the internal condition of 

the cylinder. The top of each piston is dry. This eliminates the possibility of the cylinder gasket being 

torn. Connect the diagnostic tool for self-diagnosis. There are no fault codes in the engine system and 

instrument panel. After consulting relevant information, I learned that the coolant level warning signal 

on the instrument panel is transmitted by the coolant level switch, which is located at the bottom of the 

radiator reservoir. The circuit diagram is shown in Figure 1-26. Unplugged the wiring harness plug of 

the coolant level switch and tested the car. Sure enough, a yellow warning light with a water tank 

symbol came on. Plug in the wiring harness plug and the warning light will go out. Add an appropriate 

amount of coolant to the reservoir tank and perform a road test. It is found that a small amount of 

coolant overflows from the edge of the reservoir cap, indicating that the reservoir cap is poorly sealed.

  Replace the reservoir cap and the fault is completely eliminated. 

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(3) Summary When the coolant is sufficient, the coolant level switch is closed; when the coolant is 

missing, the coolant level switch is opened and a warning message appears on the instrument panel.

  Depending on the model configuration, the coolant warning information is displayed in a different 

manner. A The formula is also different. The dashboard of some models displays text information 

through an LCD screen, and the dashboard of some models provides alarms through relevant warning 

lights. For this type of fault, not only the coolant level but also the coolant concentration must be 

checked, because the concentration will affect the float height of the coolant level switch, which in turn 

affects whether the switch can be closed.

How to Solve the Problem of BMW 318i Engine Shaking and Weak Acceleration

 How to solve the problem of BMW 318i engine shaking and weak acceleration 

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 (1) Fault symptoms The chassis model of this car is E46, equipped with an M43 engine. The fault symptoms are as follows: after starting the engine, the idling vibration is severe, the body vibration can be felt when sitting in the cab, and the vehicle cannot accelerate when driving. 

 (2) Diagnosis and maintenance From the fault symptoms, it is initially judged that there is a cylinder shortage fault. Connect the diagnostic instrument for self-diagnosis, select the "DME engine electronic servo control system ME9" item, and query the fault information. The content is shown in Table 1-3.

 

 

 

 

 

 

  In order to determine whether there is a misfire failure in the relevant cylinder, check the cylinder running stability value at idle speed, see Table

 1-4.  

 

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It can be seen that cylinders 2 and 4 have obvious misfires. After clearing the fault code and starting the 

engine, the fault became more serious and remained the same. Check the fault information again, only 

 

fault code 2745 is left, and the nature of the fault is current. Check the cylinder running stability value 

 

again. The value of cylinder 2 reaches 24.35 and it is not working at all. There are usually two reasons 

 

for cylinder shortage and misfire failure: one is poor ignition coil performance; the other is clogged 

 

fuel 

 

injector. The spark plug and ignition coil were replaced and tested, and the failure symptoms of 

 

cylinder 

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2 did not improve. The four fuel injectors were removed for cleaning, reinstalled and then tested, but 

 

the fault persisted. Use a stethoscope to check the working conditions of the four injectors. After 

 

comparison, it is confirmed that the sound of the 2-cylinder injector is weak. Check the 2-cylinder 

 

injector wiring harness connector and find a poor contact. After treatment, test run and the fault is 

 

completely eliminated. 

 

 

 (3) Summary: The engine control module identifies whether there is a speed difference in the 

 

crankshaft at a certain phase angle based on the engine speed signal, thereby determining whether a 

 

certain cylinder is defective. To this end, the engine control module continuously monitors the time of 

 

each sector working area corresponding to the crankshaft speed signal disc teeth, performs 

 

corresponding calculations, and converts it into cylinder operation smoothness data. If the running 

 

stability value of a certain cylinder gradually increases, the engine control module determines that the 

 

cylinder has a misfire fault, sets the relevant fault code, and disables the fuel injection function 

 

depending on the degree of the fault. Symptoms of this type of failure will not appear immediately, but 

 

will occur gradually. Although the fault codes can be cleared, the fault symptoms cannot disappear and 

 

require thorough inspection and elimination.

How to Solve the Problem of BMW 318i Having Difficulty Starting

 How to solve the problem of BMW 318i having difficulty starting 

 

 (1) Fault symptoms: The chassis model is E46, equipped with an M43 engine. The fault symptoms are

 

 as follows: the engine often has difficulty starting or even cannot start the car. In order to start the 

 

engine, it is necessary to press the accelerator pedal to start, so that the engine can run. 

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 (2) Diagnosis and maintenance: Confirm the fault symptoms and start the engine. Although the engine 

 

has signs of running, it cannot run. Press the accelerator pedal to start, and the engine finally runs.

 

  Observing the engine operating conditions, the idle speed is relatively stable and there is no sluggish 

 

acceleration, indicating that the problem only occurs during the starting process. Use the diagnostic 

 

instrument to perform self-diagnosis, select the "DME digital engine electronic servo control system 

 

MS461" item, and query the fault information. The fault code is 87, and the content is that the camshaft 

 

position sensor signal is missing or untrustworthy, and the fault currently exists. Check the engine 

 

operating data, see Table 1-2. All the above data are normal. Looking at the cylinder running 

 

smoothness data, cylinders 2 and 3 are working in good condition and there is no ignition loss problem.

 

Cylinders 1 and 4 have a slight ignition loss, but it does not cause starting difficulties. Based on the 

 

above inspection results, the nature of fault code 87 is that it currently exists, and the camshaft position 

 

sensor or signal is most likely to be bad, so we focus on checking this sensor. The M43 engine is only 

 

equipped with one camshaft position sensor, and its circuit diagram is shown in Figure 1 -25 shown.

 

  Unplug the sensor's wiring harness plug, turn on the ignition switch, and measure the terminal voltage 

 

of the wiring harness plug. The power line terminal voltage is 12V, the signal line terminal voltage is 

 

10V, and the ground wire terminal voltage is OV. All are normal, which means the fault is in the cam.

 

  The shaft position sensor itself. Replace the sensor, clear the fault code, test drive, and troubleshoot

 

  The status disappears and the maintenance work is completed. 

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  (3) Summary The engine has two sensors related to speed and phase: one One is the crankshaft 

 

position sensor located at the rear of the cylinder block; the other is the camshaft position sensor 

 

located 

 

 

 

 

 

 

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at the front of the cylinder head. The camshaft position sensor is a Hall-type sensor that measures the 

 

phase of the camshaft. The engine control module performs the full sequence fuel injection function 

 

based on the camshaft position sensor signal to achieve optimal control of ignition timing and fuel 

 

injection time. If the sensor fails, the engine control module activates the ignition loss identification 

 

function, starts the emergency operation program, and only performs cylinder identification once. 

 

Therefore, difficulty in starting will also occur, but there will be no obvious acceleration problems. The 

 

camshaft position sensor of the M43 engine is relatively easy to damage. If a fault code related to the 

 

sensor appears, it should usually be replaced.

​

How to Solve the Problem of Idle Speed Fluctuation in BMW 318i

  (1) Fault symptoms: The chassis model of this car is E46, equipped 

with an M43 engine. The fault symptoms are as follows: The engine 

runs for 12 There are intermittent fluctuations from time to time. 

When starting in gear or turning on the air conditioning system, the 

engine speed fluctuations are more obvious. 

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 (2) Diagnosis and maintenance: Use the diagnostic instrument to 

perform self-diagnosis and query the fault information of the engine 

system. There is no fault code. A routine inspection was performed 

and no problems were found. Replace spark plugs and fuel filters, 

clean throttle valve. Check the idle solenoid valve and find that there

 is oil in its working chamber. After cleaning it, measure its 

resistance and it is 102 [standard value is (8±2)Ω]. Reinstalled the 

idle solenoid valve and tried driving, but the fault persisted. Use an 

oscilloscope to measure the control signal of the idle solenoid valve.

 When the engine speed is 800r/ min, the signal waveform is a 12V 

square wave; when the engine speed is 1200~1500r/min, the 12V 

square wave gradually turns into a straight line, indicating that the 

control signal is good. Check the air flow sensor and measure the 

voltage at its terminal 1, there is 5V. Check the grounding condition 

of terminal 5, it is normal. Terminal 2 is the signal terminal, measure 

its signal voltage. When the engine speed is 1200~1500r/min, the 

voltage is 2.3~2.5V; when accelerating, the voltage can increase 

accordingly, which is normal. Terminal 4 of the air flow sensor is the 

signal terminal of the intake air temperature sensor. Measure the 

resistance between terminals 4 and 5. It is 23002 at 20℃ and 9702 at 

50℃, which is normal. Continue to check the throttle position 

sensor, the installation position is normal. Measure the signal 

voltage, which is 0.5V when the throttle is fully closed and 4.8V 

when the throttle is fully open. Moreover, the signal voltage changes

 evenly during the process of opening the throttle, indicating that the

 throttle position sensor is normal. Lift the vehicle and check the 

oxygen sensor, which appears to be in good condition. Use a 

multimeter to measure the signal voltage and find that the change is 

very small. When the engine speed reaches more than 2500r/min, the

 signal voltage is still 0.55V, which is inconsistent with the standard

 value, indicating poor performance of the oxygen sensor. Replace 

the oxygen sensor and the fault is completely eliminated. 

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 (3) Summary The signal voltage of the oxygen sensor should change

 within the range of 0.1~0.9V, and the number of changes per minute

 should be more than 20 times. When the mixture concentration is 

low, the signal voltage should be lower than 0.45V; when the mixture 

concentration is rich, the signal voltage should be higher than 0.45V

. The cause of the fault in this case is that the oxygen sensor is aging, 

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the signal voltage is too low, and the number of changes does not 

meet the requirements. The engine control module determines that 

the mixture is too lean based on the wrong signal and performs 

enrichment control, resulting in incomplete combustion of the 

mixture and engine jitter. The particularity of this fault is that 

although the oxygen sensor signal is inaccurate, the signal voltage is 

still within the standard value range. Therefore, the engine control 

module cannot record the relevant fault code. This requires 

maintenance personnel to check item by item through conventional 

methods, making maintenance difficult. There has been an increase.