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Fuel Pump Replacement
 
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Pelican Technical Article:

Fuel Pump Replacement

Nick Czerula

Time:

3 hours3 hrs

Tab:

$300

Talent:

*****

Tools:

Socket sets

Applicable Models:

Z4 M54 (2003-05)
Z4M S54 (2006-06)
Z4 N52 (2006-06)
M3 (N/A-A)

Parts Required:

Fuel pump module

Hot Tip:

Clean battery

Performance Gain:

Repair faulty fuel pump module

Complementary Modification:

Replace fuel pump

The fuel supply system in a BMW Z4(M) consists of:

  • Fuel tank.
  • Fuel filler with associated breathing and venting pipes.
  • High pressure fuel pump assembly with fuel filter and fuel level senders.

The fuel tank is two-lobed. There is one fuel level sender, located in the right side of the tank mounted to the bottom of tank. The right fuel tank lobe holds the fuel level sender, fuel filter and the fuel pump.

In tank fuel pumps have many benefits, the pump is submerged in fuel keeping it cool, preventing vapor lock and electrical issues. The fuel pump delivers a constant flow of gasoline to the fuel rail at a regulated pressure and volume. The fuel pump draws fuel from the fuel tank and pushes it through the fuel filter, mounted outside of the fuel tank.

The EKP control module controls the speed of the fuel pump by means of pulse width modulation of the EKP output voltage according to the fuel request. The coding of the module in conjunction with the DME software determines fuel delivery. The data is delivered over a CAN bus. The EKP control module is located in the trunk on the right side behind the battery.

When the key is turned on the EKP module is activated The fuel pump is activated at 100% for engine starting. On completion of the starting, the EKP control module regulates the EKP according to the supply rate set by the DME.

If there is no communication with the DME for example a CAN bus failure occurs and the EKP control module switches to emergency operation. The electric fuel pump is then run at 100%.

A faulty fuel pump can cause poor engine performance and hard starting problems. When it fails completely, you may be left with an engine that doesn't start. If you suspect your fuel pump has failed, you can confirm the fuel pump has received the correct voltage when commanded ON by the fuel pump relay using a digital volt ohm-meter (DVOM). If the correct voltage is present, but the pump does not activate, the pump is likely faulty. Use the DVOM in conjunction with a wiring diagram to determine the correct terminals for testing. On some models, the fuel pump is controlled by an electronic control module (EKPS), this module can fail, not sending adequate voltage to the fuel pump.

Replacing the fuel pump module on a Z4 can be done while working in the trunk. You will need to code the new module, so be prepared for that. An advanced BMW scan tool is required.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability.

Vehicle models change and evolve as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

The fuel pump module (EKPS) in BMW Z4 models is located in the right side of trunk, behind the battery--hidden by carpet trim (red arrow).
Figure 1

The fuel pump module (EKPS) in BMW Z4 models is located in the right side of trunk, behind the battery--hidden by carpet trim (red arrow).

Working in trunk, lever out the two plastic trim clips (red arrows) using a trim panel tool.
Figure 2

Working in trunk, lever out the two plastic trim clips (red arrows) using a trim panel tool.

Lift the carpet trim and remove from the trunk by sliding it straight out toward the left side of the vehicle.
Figure 3

Lift the carpet trim and remove from the trunk by sliding it straight out toward the left side of the vehicle. Loosen the 10mm nut on the negative (-) battery cable. Remove the negative cable and place out of the way in a place where it cannot come in contact with the negative terminal while replacing the battery. Flip the positive terminal protective cover up. Then loosen the 10mm nut on the positive (+) battery cable (yellow arrow). Remove the positive cable and place it out of the way in a place where it cannot come in contact with the battery terminal while replacing the battery. Disconnect battery vent hose and lay aside. Loosen the 10mm battery hold down fastener, then remove the battery hold down.

Slide the battery out of the tray toward the rear bumper (red arrow).
Figure 4

Slide the battery out of the tray toward the rear bumper (red arrow). Lift battery up and remove from trunk. Be careful and make sure you have a good grip, the battery is quite heavy.

The fuel pump module is located under the battery connection junction (red arrow).
Figure 5

The fuel pump module is located under the battery connection junction (red arrow). Start by disconnecting the module connectors (blue arrows). Press the release tabs and pull the connectors straight out.

Slide the battery junction toward the rear bumper (red arrow) and lift it up to detach the locking clips (inset).
Figure 6

Slide the battery junction toward the rear bumper (red arrow) and lift it up to detach the locking clips (inset). Once detached, lay it aside.

Remove the three plastic nuts (red arrows) for the battery junction mounting bracket.
Figure 7

Remove the three plastic nuts (red arrows) for the battery junction mounting bracket.

Next, remove the battery junction mounting bracket (red arrow).
Figure 8

Next, remove the battery junction mounting bracket (red arrow).

Loosen the 10mm fastener on the fender side of the fuel pump module (blue arrow) about 6 turns.
Figure 9

Loosen the 10mm fastener on the fender side of the fuel pump module (blue arrow) about 6 turns. Do not remove it. Then, remove the remaining 10mm fastener (red arrow).

Slide the module toward the left side of the vehicle and remove.
Figure 10

Slide the module toward the left side of the vehicle and remove. Note the inner 10mm fastener remains installed, this makes it easier to install the module later. The mounting bracket on the module is slotted. Slide new module under inner fastener, then install and tighten the outer fastener. Tighten the inner fastener. Then reverse remaining steps to reassemble vehicle trunk components.

Once the module has been replaced, clear fault codes and code and program (red arrow) the new module using an advanced BMW scan tool.
Figure 11

Once the module has been replaced, clear fault codes and code and program (red arrow) the new module using an advanced BMW scan tool.

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Page last updated: Wed 12/7/2016 03:08:11 AM