Fuel Pump PM on 2008 4.8l

[jfoj]

So I have not seen much info on fuel pump failures on the E70, however, I deal with a lot of E46 and fuel pumps make be nervous.

So I have a 2500 road trip coming up next week an decided to PM the fuel pump in my 2008 4.8l E70 with 69k miles.

The other reason I wanted to replace the fuel pump is the fuel filter is integrated into the fuel pump.

Picked up a pump at the dealer via online purchase for $281. Pump comes with a replacement gasket and hose clamp for the locking ring if you decide you need to use it.

Have replaced many pumps in E46 and E39, but not on the E70.

So I dove in to replace the pump, it is clearly a PITA as compared to the E46 and E39.

Pop the bottom rear seat, not too bad, but I have heated seats so there are a few wires and the center seat belt is threaded though the seat bottom.

Pull up a foam piece of sound proofing. The biggest PITA is the carpet covers about 2/3 of the pump access and is a pain to work around.

4 bolts to remove the fuel pump access cover.

2 separate connections, one for the fuel level sender and one for the pump power. Once the 2 connectors are removed from the pump, suggest you start the engine to bleed pressure off from the fuel line before you disconnect things.

This is where the fun starts.

First the good news is the fuel lines are quick release and do not need tools to release them. You press the colored plastic section on the fuel line connection and it will release the quick connect fuel lines.

There is a single fuel line at the top of the fuel sender.

There is a single large hose clamp that needs to be released quite a bit in order to release the plastic locking bail. You will need a 1/4" drive ratchet and 6 mm socket to reach the horizontally positioned hose clamp. The clamp is difficult to access, the only way to get the clamp loose is with a ratchet and socket.

Once the hose clamp is released, it needs to be opened up about 1" or more so the clamp is very loose, over the diameter of the pump locking ring.

Once the clamp is loose, it does not need to be removed, but the plastic locking ring is split on one end and will need to be released/opened on the split end and lifted off the lip of the tank. It is hard to explain, but it is similiar to a split rim locking ring on a truck tire.

Once the locking ring is removed, then the fuel pump can be pulled straight up out of the tank. This is tricky due to the to rigid fuel line that connects to the pump externally, but is also additionally tricky due to a quick release fitting on the top of the pump, 2 return lines that a clipped into the center of the pump and a single ground wire that with a quick connection that seems to connect to the fuel level sender in the drivers side.

It is pretty tricky to get your hands INSIDE the tank opening to release the quick connector on the filter, release the 2 hoses from the drivers side and disconnect the ground wire that is wire tied to the pressure hose that connects to the filter.

What was a bit confusing at first was the external connection on the pump sender is actually the return line rather than the supply line. The supply line is actually connected internally on the filter and is routed to the driver side likely to the sucking jet pump passive fuel pump.

Getting everything back in the tank and connected is a bit tricky. Luckily I do not have huge hands, someone with really big hands will have some challenges. The most difficult part for me was connecting the ground wire that ties into the driver side sender.

Once you are lucky enough to get everything back connected inside the tank, you then can slip the pump seal over the top of the sending unit. The gasket is then pump on the tank lip and the sending unit can be seated into the gasket. You will need to hold the pump down while trying to get the locking ring on because the pump has some 2 spring loaded shafts to keep the pump seated on the bottom of the tank.

There is a notch on the sending unit that points to the rear of the tank and there is a raised ridge on the tank toward the rear of the car that need to be lined up and the locking ring has a notch that needs to be aligned with the pump. Then the hose clamp can start to be tightened wit the ratchet. This will take a while.

I am good with my hands, I can replace a pump in an E46/E39 in under 15 minutes, this thing was starting to kick by butt!!! But I probably was able to get the job done in about 45 minutes. If I would have pulled trim so the carpet could have been pulled clear, this would have made the job much easier.

I have about 2/3 a tank of fuel in the vehicle, in hindsight, I would suggest not replacing the pump unless the tank is below 1/4 tank.

I use kitchen trash bags to cover the carpet and to put the pump in to remove it from the vehicle without spilling fuel inside or on the carpet.

Also not about a pint of fuel will be trapped inside the center of the filter near where the pump is located in the sending unit/filter assembly.

Not sure if a lot of these pumps have been failing, but with the integrated fuel filter you do not have much choice for PM and may need to replace the pump assembly. What I also noticed is the female spade terminals were pretty loose on the original pump, the replacement pump appeared to have latching female spade connectors.

I know the E46/E39 pumps fail more often in the cold weather and will also go soft and loose pressure and volume before they fail. Typically I am seeing the E46/E39 pumps lasting about 5000 hours, you cannot factor mileage life for these pumps because for ever moment the engine is running, the fuel pump is running. So a lower mileage city vehicle may have as many or more run hours on the fuel pump compared to a highway cruiser with over 125k miles. For example my 2006 E46 pump failed last November with 82k miles, but the E46 is a daily commuter in a major metro area and rarely sees over 20 MPH average speed on the OBC between each fill up.

Although this is not a DIY, it will hopefully give some an idea what may be involved in the pump/filter assembly replacement. It would also be good for anyone that has had a pump failure to report in on what year their E70 is and how many miles were on it when the pump failed.