Learn how to diagnose & repair BMW Fuel & Intake System problems:
BMPdesign will help you recognize BMW fuel and intake system problems & issues before it is too late. The following BMW fuel and intake system repair technical advice, recommendations, tech tips, and videos will teach you how to diagnose, and repair your BMW's damaged or worn fuel and intake system components.
With over 30 years experience, our BMW repair videos and instructions will give you helpful tips on weaknesses that your specific model may have. Knowing this information in the beginning will save you hundreds of dollars by aiming you in the right direction before you purchase unnecessary parts. Send us a repair request!
The electric fuel pump, usually located inside or near the fuel tank, is the heart of every electronic fuel injection system. The fuel pump sends the fuel from the tank to the injectors, and creates pressure to the injectors so the correct amount of fuel is injected. The pressure developed by the pump, as well as the volume of fuel it flows, must both meet the vehicle manufacturers' requirements or engine performance, economy and emissions will suffer.
Fuel Flow & Fuel Pressure
Driving and emissions problems occur if a fuel pump doesn't meet the OE minimum fuel or pressure volume for your BMW.
A weak fuel pump can upset the operation of your fuel system. This may cause the engine to run lean or starve for fuel under load, causing symptoms such as hard starting (hot or cold), poor idle quality, hesitation or stumbling when accelerating and a loss of high-speed power. Low fuel pressure can also cause misfire at idle and under load increasing hydrocarbon (HC) emissions, and may not pass an emissions test.
BMW Fuel Pump Failure & Diagnosis
If a fuel pump stops working with no noise, the first thing to check is the pump's voltage supply and electrical connections.
Output pressure and fuel delivery are the two standard static diagnostic tests used to determine a pump's ability to deliver fuel.
Static pressure is measured with a gauge attached to the fuel rail into the fuel supply line with the engine off and pump energized.
Fuel flow is measured by disconnecting the fuel supply line, energizing the pump for a specified number of seconds with the engine off, and measuring the volume of fuel delivered into a container.
If static pressure or the volume of fuel delivered is less than your car manufacturer's specifications, or if the pump's check valve has failed - unable to hold pressure in the system after the ignition is off, then your fuel pump should be replaced.
BMW Replacement Fuel Pump
Selecting a replacement fuel pump means choosing a pump that meets all BMW OE performance specifications and fits the same as your original.
It's important to make sure your replacement fuel pump meets all BMW OE fuel performance specifications. We supply Bosch, Hella, & Pierburg fuel pumps matching BMW OE requirements, for selected models.
BMW Fuel Pump Installation Tips:
The inside of the fuel tank should always be inspected and cleaned. Rust and debris is found may cause new pump to failure.
Always disconnect the battery to prevent any unwanted sparks. Drain the tank before removing the tank straps and opening the pump's retaining collar. Keep all flames and sparks away!
Use a new O-ring or gasket for the sealing collar, and always replace the filter screen
Do not "jump" a new pump to test it before it has been installed , or not run the pump until fuel has been added to the tank , because running a pump dry with no fuel risks damage.
Replace braided or rubber fuel lines that show signs of flaking or cracked with new EFI hose.
Parts you should consider when working on BMW fuel systems:
OEM Fuel Pump Fuel Pump Check Valve In-Tank Feed Pump (if applicable) Fuel Filters Fuel Pressure Damper Fuel Pressure Accumulator (if applicable) Fuel Distributor EHA Valve (Differential Pressure Regulator) Fuel Injectors & Fuel Injector Seals Cold Start Valve (if applicable) Fuel Injector Holders (if applicable) Frequency Valve (if applicable) Fuel Pressure Regulator, Preset or Vacuum Warm-Up Regulator, Electric (if applicable) Fuel Pump Relays Fuses Temperature Sensors (Fuel Injector Computer) Thermo-Time Switch (Cold Start Valve through ECU) Throttle Position Sensor (Throttle Switch) Position Sensors (Crankshaft, Flywheel) Oxygen Sensors Knock Sensor Air Flow Meter (Air Mass Sensor) Auxilliary Air Valve (Idle Stabilizer, Idle Motor) Idle Control Unit (if applicable) Fuel Hose (Bulk or Preformed Hose) Breather Hose (Bulk or Preformed Hose) Intake Boots
BMP Design Repair Tech Tips are added regularly. Come back often to check for new BMW Repair topics.These repair tips are designed only as a starting point. Please seek the assistance of a professional BMW mechanic for all repair problems beyond your capabilities.
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