08 GSA splutters and dies 30 seconds after starting

[Bendy toy]

The FPC provides a square wave supply to the pump to reduce its output. At low tank levels the FPC changes the mark-space ratio to drive the pump hard enough to empty the tank right hand side. Running with a non working fuel strip leaves the pump running full pelt regardless of tank level. Removing the fuel strip has the pump continuously running slow leading to fuel starvation at low levels.

You can test the pump with voltmeter prods onto the power pins. Rig them up with wire and insulating tape to the battery. If pump spins, it's probably no worse today than it was last time you used the bike. If it wont spin you've proved the pump has failed.

 

[FatBob]

The FPC provides a square wave supply to the pump to reduce its output. At low tank levels the FPC changes the mark-space ratio to drive the pump hard enough to empty the tank right hand side. Running with a non working fuel strip leaves the pump running full pelt regardless of tank level. Removing the fuel strip has the pump continuously running slow leading to fuel starvation at low levels.

You can test the pump with voltmeter prods onto the power pins. Rig them up with wire and insulating tape to the battery. If pump spins, it's probably no worse today than it was last time you used the bike. If it wont spin you've proved the pump has failed.

Having cleaned and dried the recess under the FPC the engine seems to be running OK now, better than it has for some time in fact, so fingers crossed the problem is resolved and all I need to replace is the seal under the FPC which has split. No problems in 50-ish miles on the road.

I found out some interesting things in the process though which contradict what I have read in other threads/posts here. According to the technician at Rainbow Motorcycles in Rotherham, who were a very helpful bunch:

• The live to the fuel pump is the yellow wire, not the blue one
• There is no input to the FPC from the fuel gauge, so a broken fuel strip does not mean the FPC runs at 100% all the time.

 

[Bendy toy]

Having cleaned and dried the recess under the FPC the engine seems to be running OK now, better than it has for some time in fact, so fingers crossed the problem is resolved and all I need to replace is the seal under the FPC which has split. No problems in 50-ish miles on the road.

I found out some interesting things in the process though which contradict what I have read in other threads/posts here. According to the technician at Rainbow Motorcycles in Rotherham, who were a very helpful bunch:

• The live to the fuel pump is the yellow wire, not the blue one
• There is no input to the FPC from the fuel gauge, so a broken fuel strip does not mean the FPC runs at 100% all the time.

My understanding is the fuel pump operation is controlled by the engine ECU. Three wires in. Two wires out. We are told that changes the pump controller mark-space ratio..

 

[Bendy toy]

More info here

http://www.bmwlt.com/forums/rt-series/73289-fuel-pump-controller-really-necessary.html

My bike (with no fuel strip fitted) will seemingly empty the tank with 50 to 80 miles worth of fuel remaining in the tank. At motorway speeds the level drops rapidly from about 50%. But stop and allow it to idle and the level will gradually rise back to 50%. At speed, the pump is not running hard enough to drive the injectors AND pull fuel across the tank. At tickover, it has enough to feed the ejector so fuel moves across the tank. BUT. Wait until the engine stops and you are stuffed. The ejector needs moving fuel to move more fuel (if that makes sense).

Jury rig the pump supply and it shifts fuel no problem.

A brand new pump will be able to drive both but as it wears, the output just isn't enough to do both jobs at normal pump controller voltage.

This image shows how to effectively bypass the controller. Author said cutting the blue/brown wire was a mistake - only use the brown (earth) and blue/green. I believe the controller has to be removed so not ideal but wires could be looped around the controller.

http://photobucket.com/gallery/user...nVlbF9jb250cm9sbGVyX3Jld2lyZWRfLmpwZw==/?ref=

A tip from ADV Rider to avoid the fuel pump cover filling with water - Run a cotton string (ideally a lamp wick) through a neoprene tube. Strap the tube into the cover and down the side of the tank. The cotton string will wick water out of the cover.

More bed time reading -
http://advrider.com/index.php?threads/r1200gs-fuel-pump-failure.57153/