Fuel pump controller workaround

Wapping

Moderator
Moderator
Joined
Oct 21, 2005
Messages
78,790
Reaction score
3,544
Location
Wapping, London
Robin, of this parish, was kind enough to give me the plug from the bottom of his written off fuel controller.

282269321_RuBEk-M.jpg


With this I was able to make a work around fix, enabling me to run the bike’s fuel pump without its controller, should my controller also fail.

I discovered that my controller was sitting in a deep puddle of murky water, dead flys and what our US cousins might call rocks. I call it small stones and grit. All in all, it’s not surprising water eventually gets into the controller unit, writing it off, leaving you stuck.


282259728_MKVP5-M.jpg



The controller is easy to remove, only two brass screws to undo.

282260137_qPhEW-M.jpg



Once the controller is out, you can see the plug and socket, sitting underneath.

282262089_2Bfab-M.jpg



I made a simple flying lead, using Robin’s donor plug. I had originally planned to power the plug from the switched auxiliary socket in the beak. Like most cunning plans this fell at the first. I discovered that the fuel pump must draw more than 5 amps, as the canbus simply switched off each time.

I made a second flying lead and ran it to the battery, via my Optimate’s flying lead. This gave me a suitably fused power supply. The only downside is that, as it is not switched via the ignition, the fuel pump runs continuously. This is not a problem as it is easy enough to simply disconnect the lead from the battery, no more difficult than plugging my Optimate in and out.

Whilst digging around for some connectors I found a spare Optimate battery flying lead. I will keep this to use should a friend’s (without an Optimate lead) controller break.

282259318_xf6KY-M.jpg



282258305_bmbcB-M.jpg



282258809_n7kM8-M.jpg



Having got the fuel pump spinning, I started the bike....Bingo!.....One bike running, without a fuel pump controller, without a problem. Certainly good enough to get me home.....or further.


A big “Thank you” to Robin for donating the plug.
 
solid stuff wapping.

heres a question for you, as you seem to be that way inclined.... if we can run the bike by bu-passing the relay, and a relays function (I assume) is to stop current surgess etc to the fuel pump... why do we actually need the relay? is the relay actually controling the current flow?.... yes I'm a Mechky and was lousy at the sparky bits...
 
solid stuff wapping.

heres a question for you, as you seem to be that way inclined.... if we can run the bike by bu-passing the relay, and a relays function (I assume) is to stop current surgess etc to the fuel pump... why do we actually need the relay? is the relay actually controling the current flow?.... yes I'm a Mechky and was lousy at the sparky bits...

That's a very good question....

I will ask a friend of mine - who worked, for years, for Visteon / Fords on the engine fueling side in USA and Germany, to see if he can come up with an answer. He has got a 1200 and was unaware of the failure risk.
 
i've been told 2 reasons for the pump controller...

1. there is a pressure relief/bypass valve on the 11 series bikes that is not fitted to 12 :nenau

2. it minimises electrical draw on the 1200 watch battery. don't give that one too much credence myself.
 
Alternative Solution

A good fix:thumb2
A pity that after year 4 of production the problem has still not been sorted and retrofitted under warranty for all owners.

I copied another fix from adventure rider, printed it and keep it with my vehicle documents.I have another for bypassing the sidestand switch.

Fit 2 jumper cables( std household flex will do) from Pin 1 on the external multiplug (3 pin)that fits to the top of the controller to pin 1 on the multiplug below the controller( 2 pin).

Jump from Pin 2 on the external multiplug (3 pin)that fits to the top of the controller to pin 2 on the multiplug below the controller( 2 pin).

Pin 1 is the +ve supply
Pin 2 is the -ve return.

Job done, controller bypassed and now has a direct feed. Another option if you dont have a ready made cable to bypass.

Many ways to skin etc etc..........:thumb2
 
why do we actually need the relay? is the relay actually controling the current flow


(sorry if I don't use strictly BMW terms - but I am sure the principal is the same as other FI bikes)

The pump is not running continuously.
When you switch on your ignition the ECU will prime the fuel rail with the desired pressure (on my old bike it was 3 bar). It knows the engine is not running so will stop the pump.
By bypassing the controller you are no longer controlling the pump by the ECU

The reason there is a "relay" / controller in the path between the pump and the ECU is so
1) the pump may draw too much current
2) The windings of a motor could damage the ECU, so it is used for isolation
but from what I have read the pump is damaging he solid state controller:mad:

Be grateful it's not the ECU it's knocking out :eek:



running the pump continuously - will it damage anything?
Don't know ... maybe ...
with this work around ... at the very least get your bike running as soon as the ignition is on




of course I could be talking utter balls:D
 
heres a question for you, as you seem to be that way inclined.... if we can run the bike by bu-passing the relay, and a relays function (I assume) is to stop current surgess etc to the fuel pump... why do we actually need the relay? is the relay actually controling the current flow?.... yes I'm a Mechky and was lousy at the sparky bits...

In addition the relay keeping the ECU from a voltage spike when the pump is turned. The controler/relay serves a safety function.

When you're lying in a ditch with the bike on top of you (I seem to end up this way more than I like) the ECU will turn off the fuel pump via its control of the fuel pump relay. The ECU knows when the engine is not running (no RPM signal) and turns off the pump so the fuel rail won't be pressurized.

If the injector fuel line were to become damaged (leaking) in a crash one doesn't want 40 psi of fuel pressure from the runing fuel pump pushing 5 gallons of fuel out of the tank and on to the ground.
 
Having just bought a new GS..... I'm glad I've read this! cheers.
 
Having just bought a new GS..... I'm glad I've read this! cheers.

Shouldn't be a problem on a new bike. They upgraded the controllers a couple of years ago and (touch wood) the issue seems to have been largely sorted.
 
A good fix:thumb2
A pity that after year 4 of production the problem has still not been sorted and retrofitted under warranty for all owners.

I copied another fix from adventure rider, printed it and keep it with my vehicle documents.I have another for bypassing the sidestand switch.

Fit 2 jumper cables( std household flex will do) from Pin 1 on the external multiplug (3 pin)that fits to the top of the controller to pin 1 on the multiplug below the controller( 2 pin).

Jump from Pin 2 on the external multiplug (3 pin)that fits to the top of the controller to pin 2 on the multiplug below the controller( 2 pin).

Pin 1 is the +ve supply
Pin 2 is the -ve return.

Job done, controller bypassed and now has a direct feed. Another option if you dont have a ready made cable to bypass.

Many ways to skin etc etc..........:thumb2

Hi, replying to a very old post but could you elaborate on the FPC bypass instructions please - which is pin 1, 2 or 3? Have had to actually try this out?

I have an 08 GSA which dies shortly after starting and others have suggested it sounds the the FPC. I would like to bypass it to test whether that cures the problem but searching the forum for info on FPC bypass lead this is the only solution I have found that doesn't require the connector from an old FPC, which I don't have. I don't want to cut mine in case that's not the problem! It was replaced in the recall in 2014 AFAIK.

Cheers!
 
Bob, if your FPC is silver/grey coloured rather than black, I would just change it anyway.
The earlier (silver/grey) ones were the problematic ones.
 
Bob, a simple and quick test to see if it Is the FPC at fault, just disconnect the blue pin plug from the FPC, then make up a simple 2 wire lead from the battery terminals and connect to the fuel pump. This will quickly identify if the FPC is at fault as you will hear the fuel pump working and the bike should start. If you don't understand this, then, please don't try, as this bypasses the ignition live, and will operate the fuel pump continuously. This is purely to eliminate whether its the PFC or another issue.
Wappings thread is very good if you have a spare 2 pin compatible plug, but failing that just attach a + and a - from the battery direct to the PFC.
Its your call to try.
 
Bob, if your FPC is silver/grey coloured rather than black, I would just change it anyway.
The earlier (silver/grey) ones were the problematic ones.

That was my first idea when several people suggested the problem might be the FPC, but I gather they are about £120 and I'm pretty sure mine was replaced in the recall a few years back so I would rather not spend £120 on a new one if I don't need it.
 
Wappings thread is very good if you have a spare 2 pin compatible plug, but failing that just attach a + and a - from the battery direct to the PFC.
Its your call to try.

That is the tricky bit, I don't have a spare plug to connect to the fuel pump so I need another way to do it without cutting the existing wiring.

If I unplug the connector from the top of the FPC, take a lead from the battery and splice into the wires from the bottom of the FPC going into the blue plug which connect to the fuel pump, will it fry the FPC if its not already dead? So I am supplying power direct to the fuel pump but using the blue connector while it is still connected to the FPC.
 


Back
Top Bottom