1150GS - noisy fuel pump/spluttering at half tank

[Flys Lo]

Hi everyone,

I tried searching for other people having this issue, found similar reports - but nothing exactly the same.

2002 R1150GS (single spark). About 128k km (80k miles)

When the bike gets about half a tank the bike will splutter once or twice (i.e. completely dies) - after a couple of seconds it comes back to life. Keeps the sphincter puckered if you are overtaking and there is an oncoming truck when it happens.
Once it has done this once or twice it then doesn't repeat it... although I usually find a fuel station quick smart in case the cheeky bastard repeats it in the middle of whoop whoop.


Around the same time, the fuel pump starts getting REALLY noisy. Like, louder than the engine noise noisy when the engine is under load.

I bought the bike not that long ago, and before I really rode it (i.e. noticed this problem) I changed all the fluids, plugs, plug lead on the RH head, adjusted the valves, the fuel and air filters.
Since I actually noticed the issue, I have had the injectors professionally cleaned (blasted), hasn't fixed it. Also drained the tank to get any shit out of it - hasn't fixed it either.


(my fuel guage only sporadically works as well, but I understand that to be a separate issue, most likely fixed by this: http://www.advrider.com/forums/showp...75&postcount=4 )


Any suggestions as to what might be worth looking at?
Thanks,
Adrian

[everycredit]

Did you not want someone to say you need a new fuel pump? Fine, I'll let someone else say that.

[Flys Lo]

Originally Posted by everycredit

Did you not want someone to say you need a new fuel pump? Fine, I'll let someone else say that.

I am fine with that as a response (if that is what it is )

I just don't get that it runs perfectly (and the fuel pump is silent) for the first half of the tank.
It splutters once or twice when it gets down to half, then runs fine (albeit the fuel pump is noisier)

This is my first GS, so not familiar with them, but I would have guessed that it would run like shit all the time if the fuel pump was on its way out, or is this behaviour typical of crap fuel pumps? Or do you think its worth changing it because it should fix it?

[PeterW]

I'd be emptying the tank and cleaning it.

That sounds like something floating around on the inside more than a pump problem.

Pete

[everycredit]

Floaters don't necessarily attack at and only at half-tank. Granted, it could be coincidence.

You could recheck the filter and see if there's anything nasty. Normally, I check easiest and cheapest cause and move from there. However, with fuel issues, I think the tank has to come off for all of them, so "easiest" is kind of irrelevant.

[Twilight Error]

How's your evap system? Do you have one at all? If the tank isn't venting properly, it might be causing a partial vacuum to form and that will force the pump to work harder. If you've still got the canister, try disconnecting it. If you've had the canisterectomy, blow down the vent line with compressed air (from the tank vent in the filler neck assembly).

[roger 04 rt]

I can think of a couple of possibilities.

1. Someone installed the fuel pump plate in the wrong orientation and the back end of the pump is sitting higher than it should be.

2. The evap system is clogged and causing a vacuum in the tank. With less fuel in the tank the vacuum has a more powerful effect on the remaining fuel.

[def]

There have been instances of deteriorated (brittle, cracked) fuel lines in the tank that are not visually evident. If you are headed back inside the tank (and it sounds like you might be), I would carefully inspect those tank lines. If they are cracked, the fuel pressure drops and causes engine fueling issues. Also, have a look at the fuel line clamps to insure all is snug.

If the lines are OK, I would suspect the fuel pump. If the pump is OK, I would suspect the fuel filter is at fault.

While inside the tank, inspect the tank liner if your tank is metal. These liners do fail and flake off causing all kinds of mayhem.

Keep us posted as to what you discover.

[roger 04 rt]

Originally Posted by def

There have been instances of deteriorated (brittle, cracked) fuel lines in the tank that are not visually evident. If you are headed back inside the tank (and it sounds like you might be), I would carefully inspect those tank lines. If they are cracked, the fuel pressure drops and causes engine fueling issues. Also, have a look at the fuel line clamps to insure all is snug.
...

Last summer the hoses in my tank failed to the degree that my bike would start but not run. I knew it was a pressure problem but when I opened the tank and visually inpected the hoses it appeared that the hoses had merely some fine cracks in them,

After overhauling everything it the tank (it was due) I cut the hoses open. Only then could I see the extent of the damage.

[DetourJournal]

Ya I think everyone is right, You definitely need to remove the tank and inspect the Fuel Filter and Pump for issues. It's really easy to do, in fact I just posted a Video blog showing How to replace the Fuel pump for that bike.

I had a faulty fuel pumps are not always so black and white. They can have issues intermittently, and those issues can even be so consistant that they appear to be the result of other problems.

[def]

Regarding the video, while in the tank, I would replace the fuel filter sock on the pump. Also, I would carefully inspect the tank liner for evidence of liner flaking off the steel tank.

Also, clean the fuel float potentiometer. Some owners have reported poor fuel level indication due to the potentiometer being fouled with sulphur from the fuel. A pencil eraser is used to burnish the potentiometer coil.

Also, I would carefully inspect the fuel lines for deterioration and replace as needed with the correct SAE rated fuel lines (SAE 30R10) appropriate for submersion in fuel.

Be sure the new clamps are FI rated. Worm gear style clamps are not recommended.

http://www.gates.com/brochure.cfm?br...ocation_id=541

http://www.amazon.com/AAS-Fuel-Injec.../dp/B0040CU0HM

Oh, and careful with the six 8mm bolts that hold the pump plate in place...do not overtighten and break them off.

[Flys Lo]

Thanks everyone for the responses, they helped a lot. I think I have enough here to have a look at it next weekend.
I've ordered the replacement fuel pump/filter and hoses kit from beemer boneyard.

Probably overkill, but if I am going to have the tank off (again), I figured I might as well clean it all out again and replace everything - after 10 years, it could probably do with it.

Any recommendations on how best to go about cleaning the tank? Last time I just tried my best to rinse it out with clean fuel. Probably should get the missaz to do it, she is much better at this cleaning shit than I

[roger 04 rt]

I used Beemer boneyard for everything but the submersible hose which I don't think they carry.

[Flys Lo]

Good point, just re looked at the kit, they don't include the hose. Do you happen to know that the ID (or AN size) the hose is by chance? (just so I can order it first)

Also, meant to add, did you just buy the standard Gates submersible hose and bend it to shape, or buy the original BMW hose when replacing it?
(According to your photo, and remembering the fuel lines inside, there is a sharp U-bend, I don't want to kink the hose if I just buy a foot long length and cut it to length/bend it)

[erkmania]

I didn't see where anyone mentioned opening the filler cap when the engine begins to sputter. So, I'll mention it. When you open the cap (slowly) you should here a gentle "whooshing" sound if there is a partial vacuum in the tank. That could confirm an EVAP problem if there is one.

Just filling in a minor blank left by the other and excellent recommendations.