Mercedes Mullins
The fuel pump on a BMW E90 can be replaced without removing the fuel tank. There is an access panel under the rear seat cushion that allows servicing.
A faulty fuel pump can cause poor engine performance and hard starting problems. When they fail completely, you may be left with an engine that doesn't start.
To remove the fuel pump, you will need to:
- Drain your fuel tank.
- Run the vehicle for about 20 seconds to equalize the amount of fuel in the siphon unit.
- Disconnect the negative battery cable.
- Remove the fuel cap, then slide an anti-static siphon hose down the fuel filler neck.
- Pump fuel out of the fuel tank into a suitable storage container.
- Working in the rear of the vehicle interior, grab the corner of the rear seat cushion and pull up to detach the locking tabs.
- Peel the carpet away from the right side of the rear seat cushion area of the body.
- Remove the four 10mm nuts from the access panel.
- Remove the access panel lid from the body by lifting it up.
- Disconnect the fuel pump electrical connectors by squeezing the release tabs and pulling them off.
- Remove the lines at the fuel pump by pressing the retaining tab in toward the line and holding, then sliding the line off the fuel pump module.
- Unscrew the fuel pump module threaded collar.
- Lift the fuel pump module up slightly out of the tank to access the large fuel line.
- Press the retaining tab and slide the fuel line off the fuel pump module.
- With all the fuel lines removed, lift the fuel pump module up and out of the fuel tank.
It is best to replace your fuel pump with the fuel tank drained. This reduces the amount of possible spilled fuel and fuel vapors. When replacing, work in a well-ventilated area, working outdoors is a good choice. Do not use incandescent work lights or power tools, fuel, and fuel vapors are highly combustible.
| Characteristics | Values |
|---|---|
| Vehicle | E81 E84 E90 E91 E92 E93 120i 130i 320i 323i 325i 330i 335i X1 |
| Fuel Pump Module | YHTAUTO |
Explore related products
What You'll Learn
How to test fuel pressure
To test the fuel pressure of your BMW E90, you will need to use a digital volt ohm meter (DVOM) to check the voltage of the fuel pump. If the correct voltage is present, but the pump does not activate, it is likely faulty. You can access the fuel pump electrical connector and terminals under the rear seat cushion, below an access panel.
- Remove the fuel test port cap.
- Install the fuel pressure gauge connecting line. Ensure that all test hoses are installed and routed properly. Then, install the fuel pressure gauge.
- Start or attempt to start the engine. The fuel pressure should be 5 bar (72.5 psi). Once you test the pressure, recharge the fuel system by cycling the key or running the fuel pump. Note the fuel pressure. Then, allow the fuel system to sit under pressure for 15 minutes. The pressure should drop no more than 0.5 bar in that time period. If it drops, you could have a faulty fuel pump check valve or a leak in the fuel system.
- In the rear of the vehicle interior, grab the corner of the rear seat cushion and pull it up to detach the locking tabs.
- Peel the carpet away from the right side of the rear seat cushion area of the body.
- Remove the four 10mm nuts from the access panel.
- Remove the access panel lid from the body by lifting it up. Move it away enough to access the electrical connector on the fuel pump module.
- Connect your DVOM to the terminals by backprobing. Connect the DVOM across the fuel pump terminals. The positive lead goes to the green arrow, and the black lead goes to the yellow arrow.
- Press the Start Stop key as if you wanted to start the engine. Allow the engine to crank if it doesn't start. The DVOM should read around 10 volts. If no voltage is found, check the ground to the fuel pump and the fuel pump fuse F70 in the junction box. Double-check the fuse number with your model-specific information. When the Start button is pressed, the fuel pump will receive voltage for 3-5 seconds if the engine doesn't start.
- Suggest performing a load test using a test light and a DVOM. Connect the DVOM across the fuel pump electrical connector terminals and take a reading. It should read battery volts when the key is turned on. Then, connect an incandescent bulb-style test light to the battery ground and touch the test light probe tip to the positive wire you are backprobing with the DVOM. Your reading should hold steady, with a maximum voltage drop of 0.5 volts.
- To confirm that the pump can supply fuel pressure to the fuel rail, you can manually activate the fuel pump. Use a fused jumper lead set to battery positive (+) and battery negative (-) and run the pump. The positive lead goes to the green arrow, and the negative lead goes to the yellow arrow.
Fuel Pressure Fundamentals for Ecotec Engines
You may want to see also
Explore related products
How to test fuel volume
To test the fuel volume, you will need to run the fuel directly from the pump into a container. The volume of fuel should be measured over a set period of time. This will indicate whether the pump is performing adequately.
Firstly, you will need to remove the rear seat cushion to access the fuel pump. You can then connect a container to the pump and run the fuel into it. The container should be suitable for holding fuel.
The volume of fuel should be measured over a set period of time. A good rule of thumb is to aim for a pint of fuel in 30 seconds or less. This test will indicate whether the pump is performing adequately.
It is important to note that this test does not show how the pump will perform under load. Dedicated equipment is available to safely and conveniently test both fuel pressure and volume.
It is also important to ensure safety when performing this test. Have a fire extinguisher at hand and remove any potential ignition sources, such as an incandescent light bulb, from the test area.
Checking Fuel Pressure: Holley Sniper Essentials
You may want to see also
Explore related products
How to replace the fuel pump
Step 1: Prepare the Vehicle
Before starting, ensure you have a replacement fuel pump, fuel filter, and any other components specific to your vehicle. It is also recommended to reduce the amount of fuel in the tank to prevent spillage and make the tank easier to handle. Work in a well-ventilated area, preferably outdoors, and wear safety glasses, gloves, and appropriate clothing to protect yourself from fuel spills and splashes.
Step 2: Access the Fuel Pump
The fuel pump is located on the right side of the fuel tank. To access it, you may need to remove the fuel tank from the vehicle. This process varies depending on the vehicle, but you will likely need a jack to support the tank. On some models, there may be an access port under the rear seat or in the trunk area.
Step 3: Disconnect the Old Fuel Pump
Before removing the old fuel pump, take note of the fuel line connections and wiring. Then, relieve the fuel system pressure by running the engine and pulling the fuel pump relay, or by pressing the Schrader valve on the pressure line momentarily. Disconnect all connections, turn the large lock nut, and remove the old pump.
Step 4: Install the New Fuel Pump
Install the new fuel pump by reversing the removal process. Ensure all connections are secure before reassembling the fuel system.
Step 5: Test the New Fuel Pump
Once the new fuel pump is installed, test it to ensure it is functioning properly.
Additional Tips:
- When removing the old fuel pump, consider replacing related components such as the fuel filter, fuel pump strainer, and fuel tank O-ring or gasket.
- If you are unable to drain the fuel tank, use a ratchet strap to tie the tank to your floor jack for support.
- If you encounter rusty fuel lines, cut the side that is being replaced, as fuel lines are not a common part.
- If there is a metal ring holding the fuel pump in place, be careful not to damage it during removal, as it is cheap to replace.
Understanding Fuel Pressure Requirements for a 302 EFI Engine
You may want to see also
Explore related products
$80.48
How to replace the fuel pressure regulator
To replace the fuel pressure regulator in your BMW E90, follow these steps:
Step 1: Remove the rear seat cushion.
Step 2: Disconnect the negative battery cable.
Step 3: Remove the fuel cap.
Step 4: Drain the fuel tank.
Step 5: Disconnect the fuel pump electrical connectors.
Step 6: Remove the fuel lines at the fuel pump.
Step 7: Unscrew the fuel pump module threaded collar.
Step 8: Remove the fuel pump module from the tank.
Step 9: Install the new fuel pump module, ensuring the O-ring is properly seated.
Step 10: Reconnect the fuel lines and electrical connectors.
Step 11: Refill the fuel tank and check for leaks.
Fuel Pressure and Injectors: What's Too High?
You may want to see also
Explore related products
How to replace the fuel filter
To replace the fuel filter on your BMW E90, you will need to access the fuel pump, which is located on the right side of the fuel tank. The fuel filter is part of the fuel pump assembly, so you will need to remove the fuel pump module to access and replace the fuel filter. Here is a step-by-step guide on how to do this:
Step 1: Disconnect the negative battery cable.
Step 2: Remove the fuel cap and use an anti-static siphon hose to drain the fuel tank. Run the vehicle for about 20 seconds to equalize the amount of fuel in the siphon unit.
Step 3: Access the fuel pump. There is an access panel under the rear seat cushion. Remove the rear seat cushion by grabbing the corner and pulling up to detach the locking tabs.
Step 4: Disconnect the fuel pump electrical connectors. Squeeze the release tabs and pull off the connectors.
Step 5: Remove the fuel lines at the fuel pump. Press the retaining tab towards the line and hold, then slide the line off the fuel pump module. Be careful not to damage the hose or fuel pump module.
Step 6: Unscrew the fuel pump module threaded collar. You can use a BMW special tool (#16 1 022) or a brass punch and a rubber mallet. Tap the threaded collar counter-clockwise to loosen it, then unscrew the rest of the way by hand.
Step 7: Remove the fuel pump module. Lift it slightly out of the tank and disconnect the large fuel line by pressing the retaining tab. Work slowly and carefully to avoid damaging the line.
Step 8: Install the new fuel filter. Attach the new fuel filter to the fuel pump module, ensuring that all connections are secure.
Step 9: Reinstall the fuel pump module. Lower the fuel pump module back into the fuel tank and hand-tighten the threaded collar. Use a BMW special tool or a brass punch and rubber mallet to tighten it further.
Step 10: Reconnect the fuel lines and electrical connectors. Ensure all connections are secure.
Step 11: Refill the fuel tank and check for leaks. Fill the fuel tank with about 2 gallons of fuel before attempting to start the engine. Once the fuel pump is operating normally, fill the rest of the fuel tank and check for any leaks.
Restarting Your Engine After Fuel Pressure Loss: A Guide
You may want to see also
Frequently asked questions
To remove the fuel pump from your E90, you will need to disconnect the negative battery cable, drain the fuel tank, and remove the rear seat cushion. You will then need to remove the access panel and disconnect the fuel pump electrical connectors and lines. Finally, you can remove the fuel pump module.
To test the fuel pressure on your E90, you will need to connect a fuel pressure gauge to the fuel test port and start or attempt to start the engine. The fuel pressure should be 5 bar (72.5 psi). You can also use a digital volt-ohm meter (DVOM) to test the voltage at the fuel pump electrical connector.
If your E90 fuel pump is faulty, you may experience poor engine performance, hard starting problems, or an engine that doesn't start at all. You can use a DVOM to test the voltage at the fuel pump electrical connector and compare it to the correct voltage specified in your vehicle's wiring diagram.
To replace the fuel pump on your E90, you will need to remove the rear seat cushion and access the fuel pump module. You will then need to disconnect the electrical connectors and fuel lines before removing the fuel pump module. Be sure to replace the fuel pump sealing O-ring and fill the fuel tank with about 2 gallons of fuel before attempting to start the engine.
If your E90 fuel pressure regulator is faulty, you may experience long cranks, rough idle, or a gas smell. You can test the fuel pressure using a fuel pressure gauge and compare it to the specified pressure for your vehicle. If the pressure is low, you may need to replace the fuel pressure regulator.
