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BMW Fuel pump control module

Started by The Bikle Shop, February 14, 2018, 08:44:29 AM

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The Bikle Shop

For you mostly F800 people out there you should know about this. It could get you all the way home.
I didn't think about doing this write up when I started. So there are not a bunch of pictures. There should be enough to show you the critical things in the 2 I have though.

The problem is (in my opinion) that the control module in down in a hole with little air flow and over heats. Once this happens the controller will sometimes cut back on after it cools off. This cutting back on will only happen a few times at best. You can fix it on the road if you know what to do.

So here is one way to fix it,
And this is the most elaborate of the fixes.

To start the controller is mounted on top of the fuel pump under the seat. 
1  Unplug it.

2 There are 2 torx screws that hold it down. Remove those, and pull the controller up.

Pull the control module up gently. It has a formed O-ring seal. As well as being plugged into the top of the pump access flange.
If you do tear the O-ring the new controller comes with one.

3 Unplug the controller from the flange.

If you are on the side of the road you can skip the next steps. Just cut the wires off as close to the board as possible, because this is where things start to change according to where and when this failure happens. If you are in the middle of the woods. With almost no tools. Strip the wires back on the 2 pin plug you cut off. Stick the Blue in the center pin of the plug that is still on the bike. Stick the Yellow wire in the pin location closet to the sharp corner of the controller.

4 Now the fun part take a pocket knife, xacto, or event a pointy stick and remover the silastic/sealer compound from the back/underside of the controller exposing the computer board.



5 It's a tight fit but pry the computer board out. You can desolder the pins in the plug going through the cast body of the controller as I did.
You can also cut the plug out of the cast body. If you do this. you will just make a pigtail without the controller body to seal the hole back up. As you can see in the picture below the top of the board is coated in silastic so the board can be a pretty difficult to remove.



6 Solder the blue wire to the center pin in the plug. Solder the yellow wire to the pin closest to the tight corner of the controller body.
  I also heat shrank the connections to help with strength.


7 plug every thing back in and ride.

Now keep in mind you have eliminated the fuel pump controller. This will cause the pump to run at 100% duty cycle. This can cause the pump to over heat, the fuel pressure be way to high, and a few other problems.

ONLY DO THIS MOD AS A LAST RESORT. THIS IS AN EMERGENCY FIX TO GET YOU TO SAFTY. HAVE THE BIKE REPAIRED PROPERLY AS SOON AS POSSIBLE.





KrisCook

This was part of his desperate effort to do whatever it took to make me quit calling him to bring the trailer to pick me and Twitch up.  First the start switch failed, then the fuel gauge failed, then the fuel pump controller failed.  WTF BMW

 
Sounds good except for pretty much everything you said.  ---Brian A

2019 Honda Rebel 500
2018 Honda Grom