BMW F 800 GS intermitent stalling every 10-15 seconds

[rlopes]

During my last trip in Morroco two weeks ago I experienced an intermitent engine stalling every 10 to 15 seconds.
In fact I've meet at least 3 other travellers in the road and with same engines reporting exacly the same problem (2 of them from UK).
The symptoms are quite simple to report. Bike runs well in the morning but after something like 2 hours riding it just starts to cut engine in intermitent 3-4 seconds periods. Imagine running 15 seconds ok, 4 seconds cut, 15 seconds ok, 4 seconds cut,..... mostly at low speed/revs and especialy when act on the throtlle. The cut is similar to fuel fault.
At Zagora I cleaned all the fuel tank and pump net filter, without success.
I decided to do a diagnostic in the BMW dealer at Marrakech but nothing was reported... 50eur for nothing :angry:
Anyway I managed to return to Lisbon by highway, with a couple of more fails.
Of course I've already reported the problem to my local BMW dealer, but as you can imagine they just ask me to send a email to BMW.... so no comments here....
After all I still have no idea about what can be causing such a "stoppable" problem.
One think I can confirm... since I added european fuel into the tank I've never detected the problem again but a possible candidate is the pump itself.
Can someone please comment or had the same experience?

Many thanks in advance

Renato
Lisboa

 

[slparry]

If you go to youtube and search for F800 stalling there's quite a few instances

https://www.youtube.com/watch?v=uDTV_8e6VmE

 

[harry the cat]

Been there!

I had a similar problem a few years ago which started while I was riding in Spain in hot temperatures and continued intermittently. Usually involved hot weather and an emptying fuel tank. Never showed up on diagnostics. I only cured it by changing the fuel pump and the fuel pump controller.

 

[rlopes]

Thanks slparry for the 30 min. video. Imagine my 10 days Morroco trip....
I don't want to enter in a fight with BMW to replace fuel pump. But at least I want from them to present me with possible causes for the fact.
Unfortunately, from my experience, BMW technicians are becoming more part movers than experienced mechanics...
Before the problem i did the 30k km service in my dealer, the same that on my return asked me to send a email to a very generic BMW email address.... so no comments

If someone can help me with more information I woul be pleased.

Renato

 

[GSKev]

Fuel Pump ?

Hi Renato - similar problem:
Maroc last month and as soon as I got to the desert the bike started stuttering - as if suffering from fuel starvation. Now this bike has been to Morocco before and ran faultlessly. Established that it only did it after about 100 miles from filling it up with fuel and the cure was to completely fill up again ! By doing this I was able ride but the distance it would go became less and less - down to 65 miles before stuttering at one point. The bike never however cut out completely. Met a BMW tech in the Dades and he suggested opening the filler cap and shaking it (vent the tank) but this didn't work - only thing to do was fill it to the brim and it would run no problem - albeit my range was dramatically reduced. Adv Rider has some threads that suggest that what is happening and my read is as follows - (could be wrong):
Fuel pump at top of tank becomes exposed as fuel level drops. In very hot temperatures the pump inside the tank then starts to overheats as it is exposed by the dropping fuel level. When the tank is then refilled the pump is immersed in the petrol that cools it and the cycle starts again. I don't think it has anything to do with fuel quality.
I'm currently waiting for a Bosch pump because BMW will only supply the complete fuel pump unit including the fuel filter and guage sender unit - £300+ . Various pumps are available inc cheap Chinese ones on Ebay (about £20-30) but I've opted for a Bosch - the threads identify a number of alternatives mainly from the car market but even the Bosch are under £100.
Here's a video covering the fuel pump replacement:
http://www.youtube.com/watch?v=BAVYghrAlYc
I'll let you know how I get on after changing the pump but I think the problem will be hard to replicate here in the UK as the ambient temperature does not get hot enough.
I'll watch this thread with interest.

 

[rlopes]

Thanks a lot for sharing gskev
It's unbelievable how these supposed unstoppable bikes fall in an environment they were designed for.
We were a group of 11 bikes from all makes and ages and no other had any kind of problem.
Amazing the fact of all BMW twin engines I found during that days had exactly the same issue.
Definitely BMW should care about it. It's not acceptable. Amazing the fact that when reported it to BMW staff they said never heard about it. How can be possible?
Regarding the bosh pump, where did you order it? Any online shop?

Regards

Renato

 

[vaclove]

I have experienced and reported the stalling issue as well, few years ago. Similar scenario - it was in France, very hot weather and it happened when the tank was not full. BMW garage did the diagnostics and they found some leave or piece of wood in the radiator fan. They have claimed, that the fan failed to cool the engine, therefore it was cutting off....
I like the theory of gskev, but I got another one. While the issue is known and BMW do not really have an idea what it can be, I think it can not be really construction error, otherwise it would be happening at all bikes and they would know the solution.

I now this is a speculation, but I think it might be water in the fuel. F800GS is bit more fuel demanding than F650GS (needs 95 octane fuel rather than 91).

The fact that you met other guys experiencing the same issue makes me think it has something to do with the location (they could easily buy fuel at the same station on the same roadside as you did). Morocco is hot and dusty, but it is not the only hot and dusty place where the bike is ridden. And since you did not experience the problem since back in Portugal, I don't think is the pump.

 

[rlopes]

Well... Decided to replace the pump. Ordered a cheap one from eBay and did the change.
Bike running well but had no chance to replicate the issue conditions yet - possible poor quality fuel and hot climate.
Anyway I have no doubt that If was the poor fuel quality then something in the engine management (sensor, etc) is responsible for the power cut. But why bike ran great during the first ride hours, always in the morning when fresh?

 

[Smythson]

Hi,

Though it may not be a solution, it may well be an aggravating factor - the fuel tank vent hose is made of aluminium and attracts corrosion (a sort of white powder) which means when you open the filler cap it makes a sucking noise. This may mess with the pressures and the amount of work the fuel pump has to do against the vacuum.

It's quite easily cleaned and more importantly costs you nothing!

Best,

S