Fuel pump failure & backpressure

[Roger Chatterton]

Just got back from the Dracula Rally in Transylvania, but had a fuel pump failure on the way. Fuel pump just cut out whilst waiting at traffic lights. I eventually managed to remove fuel pump, and sure enough, pump was not working when connected to the battery. However, before removing the pump,there appeared to be a vacuum building up in the tank; a hiss of air entering the tank when opening the filler cap.
After much messing about, we managed to get the fuel pump to work, partly by pressing on the small silver metal strip near the contacts -this seemed to release pressure on the pump- connected pump to the battery, and sure enough, the pump started running again.

Couldn't wait for delivery of new pump from Motorworks, so re-installed the "repaired " pump, which ran fine for nother 400 - 500 miles, across the mountains into Bulgaria, where, once again it failed. I had been ruuning with the filler cap held slightly open with gaffa-tape, in case the vacuum build-up was causing pump failure.
To cut a long story short, 2 mechanics in Bulgaria managed to source and fit new "non BMW" fuel pump with little problem, and pump still working after another 2000 miles through Italy and Greece ( still left fuel filler cap slightly open just in case).

So, I am very curious as to what caused the problem, ie ,
1. did the fuel pump failure result in a back-pressure in the tank, or
2. did the back-pressure cause the pump to overheat and fail, or
3. could dirt have got into the pump ?
4. is there a "release" valve in -line somewhere that caan get blocked, or is this part of the fuel pump itself ?

Apologies for long winded explanation, but wanted to give as much info as possible.....

PS.....Roads in Romania were just as bad as everyone says, and look out for cows wandering around.... !!!!

 

[Dragon Master]

Check your tank breather pipes; they dangle down the right-hand side behind the footrest hanger. Wipe the ends and just blow in to them, if either is blocked you won't be able to.

I had the 'back pressure' vaccuum problem when I first got my 1100; it would suck the wings of the tank in on a long enough journey. One day it sucked a dent in to the side of the tank; I thought some scrote had been giving it attention at first. It eventually sucked once too often and put a crease in the tank. Fuel pump kept going all through, but it is definitely noisier now than when I got it.

One of the pipes was blocked; where it comes out of the pump mounting plate and does a right-angle, it had rusted and bunged up.

Cheers,

Dave.

 

[Dragon Master]

they dangle down the right-hand side behind the footrest hanger.

Er, yeah, you'll know that because you've had the tank off...

Dave.

 

[Roger Chatterton]

Hi Dave, that sounds like a possible....I'll be doing a more "permanent " repair soon , so I'll check the breather pipe. The overflow pipe was fine, but I wasn't able to blow into the breather pipe.
Also, why do BMW use those poxy cheap crimped jubilee type clips to secure hoses -bloody nightmare trying to re-use for the pipes that connect to the pump and pipes....think I'll get proper Jubilee clips and hang the expense

 

[Roger Chatterton]

Here's the Bulgarian team in action ....note the size of the guy on the right - we had to physically LIFT the 1150, with an almost full tank, into the back of a Transit to get it to the workshop; there was no ramp provided on the recovery vehicle. Good job he was built like a bear

 

[davegs]

Bulgaria

for service you can't beat these guys they were brillient but rather large so don't argue about the small bills!! They new what the pump came off and piled inot their car and got one brillient. About the only thing that is.
dave gs.

 

[Steptoe]

for service you can't beat these guys they were brillient but rather large so don't argue about the small bills!! They new what the pump came off and piled inot their car and got one brillient. About the only thing that is.
dave gs.

Looks like the medication is starting to wear off.

 

[Roger Chatterton]

Having looked into the whole fuel pump problem further, it appears that there is an air intake valve that allows air to replace used fuel in the tank. The intake for this is one of the 2 rubber pipes that sit to the right of the tank,along with the fuel overflow pipe from the filler cap.
The valve ( I think they call it an anti-roll over valve or something like) is situated next to the fuel filler cap, and is accessed by removing the filler cap etc. Does anyone know if this valve is easy to check (ie via an air line ?), and does anyone happen to have a spare one that they know works . I guess the purpose of this valve is also to prevent fuel spillage for if (when !!!) you drop the bike. There is no mention of this valve in my Haynes manual, but does show in the online 1150 info I downloaded via this site.

Also, final thing for the moment - is it possible to get fuel pumps serviced or rebuilt ? They appear to be a sealed unit, kind of "crimped over" at the top, so looks unlikely, but worth asking !

 

[motobiker]

I would've thought thet the most sensible mod you can do before touring abroad is to move the fuel pump outside the tank... plenty of info on this site about that.

 

[Roger Chatterton]

I would've thought thet the most sensible mod you can do before touring abroad is to move the fuel pump outside the tank... plenty of info on this site about that.

I was wondering about that, and it seems a sensible idea...I'll do a search !
Have you done this yourself by any chance ?, and any problems ?

 

[motobiker]

No... not done it myself... but then i've not ventured as far east as the OP. Just done a quick search myself and found this - http://www.ukgser.com/forums/showpost.php?p=1163051&postcount=10

So maybe its not such a good idea.. unless of course you are going well off the beaten track... and anticipate doing well over 24K miles... who knows?

 

[cookie]

I was wondering about that, and it seems a sensible idea...I'll do a search !
Have you done this yourself by any chance ?, and any problems ?

more sensible to just move the filter

little point unless you're doing high mileages IMO. i actually did the outboard filter conversion, but reverted back as it looked a dog's dinner.

2p

 

[davegs]

Fuel pumps

This thread relates to the fuel FILTER not the pump. Putting the pump out side would be a major operation / re-design as the pump requires to be in the petrol for pick up and cooling. I still think there's a roll over valve in the breather which has got stuck. But this man picks the best places to break down, first time out side the only decent (very good ) Italian resturaunt in Romania. After he'd been picked up the two of us remaining were dragged in to it and very well fed with two courses many beers for about the equivilant of 8euros between us Exceptional food and a very silly price but thanks to all concerned.
dave gs. ( Could the Bulgarian mechanics be a branch of Steptoes?).

 

[Roger Chatterton]

. ( Could the Bulgarian mechanics be a branch of Steptoes?).

Bulgarian Bear spoke no English, and Steptoe is nothing if not fluent

And there was me feeling sorry for you 2 guys left behind whilst I got a lift in the trailer...and bloody hungry too. Guess I missed out on that rare thing, a well served Romanian meal !!! See ya soon Dave.

But to return -any one know about fuel pump repairs or re-builds ?

 

[davegs]

Fuel Pumps!

Roger, you can get one from Motor works!!(sorry that was cruel!!!!)
See you at Dave's.
Dave (Abba fan ) GS.
Lesson for today, Go and see Mamma Mia with Merle Streep, brilliant film even better than motor bikes!!!!.

 

[Roger Chatterton]

Dave (Abba fan ) GS.
Lesson for today, Go and see Mamma Mia with Merle Streep, brilliant film even better than motor bikes!!!!.

You old perv, how can Meryl be better than motor bikes

 

[Renatus]

Having looked into the whole fuel pump problem further, it appears that there is an air intake valve that allows air to replace used fuel in the tank. The intake for this is one of the 2 rubber pipes that sit to the right of the tank,along with the fuel overflow pipe from the filler cap.
The valve ( I think they call it an anti-roll over valve or something like) is situated next to the fuel filler cap, and is accessed by removing the filler cap etc. Does anyone know if this valve is easy to check (ie via an air line ?), and does anyone happen to have a spare one that they know works . I guess the purpose of this valve is also to prevent fuel spillage for if (when !!!) you drop the bike. There is no mention of this valve in my Haynes manual, but does show in the online 1150 info I downloaded via this site.

I've got the same vacuum problem in the tank. The pipework is clear all the way up to that anti-rollover valve so does anyone know how it works or how to test it?