BMW Fuel Pump: Common Problems And How to Test

Faulty BMW fuel pump can cause poor engine performance and difficulty starting. If you suspect that your fuel pump is faulty, please compare it with the symptom information provided by Eurocartool experts below. This will help you identify the cause and fix it in time. Let’s follow along!

BMW High Pressure Fuel Pump Problems

BMW fuel pumps do not have any warnings on the dashboard or Check Engine light when they malfunction. However, there will be a phenomenon based on some of the following signs:

• Difficult to start after the engine is cold
• Can only start once in the morning
• Noisy fuel tank
• Abnormal fuel consumption
• Abnormal decrease or increase in exhaust gas
• No noise in the fuel tank

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Detailed descriptions of the signs of fuel tank failure will be described in detail below:

The fuel tank makes a strange noise

It is normal for the fuel tank to make noise when it is pressurized, however, if this noise becomes louder or makes a creaking noise, it is a sign of a serious problem. It can include fuel damage, insufficient fuel level, or fuel contamination.

The car is difficult to start or stalls

A faulty fuel pump will not provide enough fuel for the engine to operate, which can lead to frequent stalling. The temperature gauge will also show a high temperature before your BMW stalls.

In addition, if the fuel pump is worn, it cannot provide the correct amount of fuel at the right time. This leads to an imbalance of fuel-air in the engine. The combustion process is distorted and makes it harder to start.

The engine consumes more fuel

When driving at high speeds, the fuel pump needs to work more than normal to provide fuel. If it is damaged, the lack of fuel needed to meet the engine will cause the engines to jerk. Besides, the amount of fuel supplied exceeds the prescribed amount, leading to excessive consumption and unstable vehicle speed. This is a serious hazard and indicates a fuel pump failure.

How to Test High Pressure Fuel Pump

The operation of the high-pressure BMW fuel pump is monitored by the engine control unit (ECU). Therefore, any errors in the system pressure will be detected by the pressure sensor and stored in the ECU’s error memory. You can use a suitable diagnostic tool to read the codes and troubleshoot the issue.

Here are some ways to test the fuel pump:

Visual Inspection

Visually inspecting the BMW Fuel Pump system components can help identify problems such as leaks in the fuel line or faulty plug connections on the sensor.

Using a Diagnostic Scanner

As mentioned above, all error codes will be stored in the memory and you can access them using a diagnostic scanner. After connecting the diagnostic plug to the fuel pressure regulator valve, you will see the error code P2294 appear on the scanner screen.

The error code P2294 – Fuel Pressure Regulator 2 Control Circuit/Open can be caused by the following:

• Open circuit
• Loss of signal/no communication with BMW Fuel Pump
• Permanent fault

Reading Parameters

Check the high and low pressure sensor parameters from the ECU to assess the system pressure and find the possible cause of the error.

To check and evaluate the system pressure, you first need to look at the parameters of the high and low pressure sensors from the ECU.

To narrow down the possible causes of the error, the actual values displayed can be compared to the target values set by the vehicle manufacturer.

The high-pressure circuit is always checked after the low-pressure circuit has been checked and no fault has been found.

Checking Low Fuel Pressure

The low-pressure fuel pressure sensor is installed in the supply line to the high-pressure pump and sends a signal to the engine control unit.

Using this information, the engine control unit can calculate the required low pressure and send a signal to the fuel pump controller to activate the pump as needed.

If the sensor is faulty, the pre-feed pump is controlled by the engine control unit with a fixed value and the pressure will be increased accordingly. If the fuel pump controller is faulty, the pre-supply pump will not be activated.

Checking High Fuel Pressure

The high-pressure fuel pressure sensor is screwed into the distributor (rail) and sends a signal to the engine control unit. The data is evaluated in the engine control unit and the high pressure is adjusted accordingly via the high pressure control valve.

If the sensor is faulty, the valve will be activated by the controller with a fixed override value.

Preventing BMW Fuel Pump Problems

BMW fuel pump problems are often caused by dirty fuel, dirty filters, or electrical problems. Therefore, to prevent these problems, you should do the following:

Use high-quality, appropriate fuel: BMW engines typically use a type of fuel specifically manufactured by their brand. If you want your engine to always be in top condition, stop using low-quality fuel because it contains a lot of impurities and can lead to clogging of the fuel system.

See Also: How To Repair BMW Fuel Pump Control Module Failure Symptoms 

Make sure the gas tank is always full: The fuel pump will tend to break down if you use the car with low gas levels regularly. In addition, the fuel pump is cooled by the fuel surrounding it in the gas tank, so if the tank is low it means it will be exposed to more heat and is at a higher risk of overheating.

Maintain the fuel filter regularly. Contaminants are retained when fuel passes through the filter. If you do not clean the filter after using it for a long time, all debris and dirt will clog and fuel will not be able to be supplied sufficiently for the combustion process. This will become a potential hazard for the entire engine.

Once you have confirmed the signs that the BMW fuel pump is damaged, you should quickly proceed to repair it to avoid more serious damage. In addition, in some cases the BMW fuel pump may give false warnings due to a sensor error, to save the cost of replacement, you can use the coding and reprogramming method. However, the operations need to be performed by experienced technicians. Contact WhatsApp: +13155472355 for support from Eurocartool experts.