Low Fuel Light Not Working

Post your F Series Technical Q&A's here

Moderator: Moderators

F650GS Low Mileage
Forum User
Posts: 4
Joined: Sat Jun 03, 2017 11:05 am
Country of Residence: England
Location: Altrincham, Cheshire

Low Fuel Light Not Working

Postby F650GS Low Mileage » Sat Jun 03, 2017 11:18 am

Hi guys,
This is my first post...........
I have a 2004 F650GS with 1800 miles on the clock. I've owned the bike for almost 4 years but don't ride it very often.
I rode it for the first time this year earlier this week and ran out of fuel!
I've put approx. 4 litre in the tank. I've checked the electrical continuity across the pins of the sender and the circuit is closed. I haven't yet put more fuel in the tank and checked that the circuit becomes open, ie that the sender is fully working.
Before I remove the fairing to access the rear of the instrument panel to check the bulb, are there other checks that I could do?
Is this a common failure?
Thanks for any advice on this, much appreciated.

User avatar
Galactic Greyhound
Moderator/Club Member
Posts: 7506
Joined: Sat Aug 28, 2010 11:26 pm
Country of Residence: Scotland
Location: Dumfries

Re: Low Fuel Light Not Working

Postby Galactic Greyhound » Sun Jun 04, 2017 9:42 pm

Hi,

Welcome to the forum!

I'm not familiar with the F Series.

I have a library of Wiring Diagrams for various bikes but not for a 2004 year F650GS.

I have a 2006 - 2010 F650GS Wiring Diagram which is for CANbus bikes - does your 2004 bike have CanBUS?

CANbus
If so, then the Fuel Sensor Level Sensor is shown as a 2-pole variable resistance sensor connecting to the Central Chassis Control Unit (ZFE) pins 21 & 37 via a 2-pole connector.

If you can locate this 2-pole connector and disconnect it, then, you can put a variable resistance pot (from Maplin & the like) across the pins going back to the ZFE and simulate from Zero Ohms upwards.

Looking at the diagram, I don't think that the Sensor actually goes open circuit but rather varies from Zero Ohms upwards.
This might be the best way to check that the ZFE responds to a Low Fuel signal.

It is not clear if the sensor is a float arm wiping a resistance track inside the tank.

Do you have a Haynes or Clymer Service Manual?
If not, it is well worth purchasing one if you intend to do DIY work on your bike.

Non-CANbus
If your bike is NOT CANbus, then you may just have a float arm sensor working via a damping relay to your Low Fuel indicator and it may be that an open-circuit condition triggers the Low Fuel indicator.
Again, a Haynes or a Clymer Manual will explain what is going on and how to test it.

I would have thought that putting 4 litres into the tank would have reset any Low Fuel warning.
It may be that the sensor/Float Arm Track/Warning bulb is faulty.
See if your User Manual shows a Low Fuel Warning relay and you might be able to check the bulb operation/sensor operation via the relay.

It is good practice to ALWAYS set your Trip Odometer to Zero each time you brim the tank.
That way you will learn how far you can go before requiring to refuel.

Put a post in the 'Introduce Yourself' section telling us where you are located and a bit about yourself.
Keep an eye on the Events Calendar for any meets/events which might appeal to you and where you can discuss your bike with others - we're a friendly bunch here! :smile:
Ced.

R1100RT 1996.
Sent by Boson Quantum Transmission from the Starship 'Galahad'.
http://www.researchgate.net/publication ... ing_bosons" onclick="window.open(this.href);return false; - It works!

F650GS Low Mileage
Forum User
Posts: 4
Joined: Sat Jun 03, 2017 11:05 am
Country of Residence: England
Location: Altrincham, Cheshire

Re: Low Fuel Light Not Working

Postby F650GS Low Mileage » Mon Jun 05, 2017 9:24 am

Many thanks for taking the time to post such a comprehensive response, much appreciated.

I have the Haynes manual. My bike was first registered in May 2004. According to the wiring diagram for the 2004 to 2007 GS and Dakar, the fuel level switch is clearly shown as open/closed. When closed (more than 4l according to the Rider's Manual), the signal goes to a transistor located within the instrument cluster and from there to the warning light bulb.

The GS and Dakar to 2003 don't seem to have a low fuel indicator at all. The CS version to 2003 has a variable resistance fuel level sensor but by 2004 this had been replaced by the on/off switch version.

I certainly get the point regarding zeroing the trip odometer. I'm very much a fair weather rider and I don't like leaving a lot of fuel in the tank for long periods as it's prone to go stale giving impaired engine performance (from my experience of dinghy outboard motors). I must admit that the last time I put fuel in the bike was 2015! Last year was pretty busy with one thing or another and I drove no more than the 3 miles to MoT station and back! I've now taken early retirement so I have more time to enjoy the bike.

The weather forecast here in South Manchester today is poor so I'm unlikely to start removing the body work just yet.

Before the F650GS, I was on the "dark side" as I owned a GPX for more than 20 years.

User avatar
george baker
Moderator/Club Member
Posts: 6173
Joined: Mon Aug 01, 2005 10:51 am
Country of Residence: uk
Location: Manchester,UK

Re: Low Fuel Light Not Working

Postby george baker » Mon Jun 05, 2017 11:50 am

Hi
Can you let us know which 650 it is if you post again please cos the dual us by BMW of F650GS makes giving help hard

I don't like leaving a lot of fuel in the tank for long periods as it's prone to go stale giving impaired engine performance (from my experience of dinghy outboard motors).
I understand your reason, but keeping the tank full of fuel keeps water from condensing


The weather forecast here in South Manchester today is poor so I'm unlikely to start removing the body work just yet.
The actual weather in North Manchester is not too bad, if you put your location in your profile you should get local invites, eg last week we were in Rawtenstall

George
Member 21, R100R, K75 and a Hyosung 250 FOR SALE

F650GS Low Mileage
Forum User
Posts: 4
Joined: Sat Jun 03, 2017 11:05 am
Country of Residence: England
Location: Altrincham, Cheshire

Re: Low Fuel Light Not Working

Postby F650GS Low Mileage » Mon Jun 05, 2017 7:32 pm

Hi George,

Thanks for the response.

The logbook shows the model as F650GS 04. Does this help?

I understand the point regarding water condensation in the tank. I also have a sailing boat and it's imperative to keep the diesel tanks full over winter. Water in diesel promotes "bug" and this can cause all manner of problems on a boat. For my bike, on the one side my fuel will deteriorate, on the other water may condense in the tank. Clearly the best solution is to use it more!

I'm in Altrincham and I'll change my profile location accordingly. A very welcoming comment, much appreciated.

Yes, the weather in South Manchester was miserable all day today and the forecast for tomorrow isn't much different. Can't see myself venturing into the garage just yet!

User avatar
george baker
Moderator/Club Member
Posts: 6173
Joined: Mon Aug 01, 2005 10:51 am
Country of Residence: uk
Location: Manchester,UK

Re: Low Fuel Light Not Working

Postby george baker » Mon Jun 05, 2017 7:52 pm

Hii think you have a singlee cylinder bike. Tomorrow i will be using my bike to go in to the centre of town whatever the weather
George
Member 21, R100R, K75 and a Hyosung 250 FOR SALE

F650GS Low Mileage
Forum User
Posts: 4
Joined: Sat Jun 03, 2017 11:05 am
Country of Residence: England
Location: Altrincham, Cheshire

Re: Low Fuel Light Not Working

Postby F650GS Low Mileage » Wed Jun 07, 2017 1:02 pm

Hi George,

Yes, it's single cylinder.

I spent the morning in my garage removing the bodywork. Removing the front mudguard was surprisingly difficult. The 4 bolts had Loctite on the threads and were very unwilling to undo. I only had the star head keys from the bike tool kit and these were prone to slipping out. I made a quick visit to Halfords to buy a set of socket drives, much easier.

I was sceptical that the bulb had blown because I don't think I've ever know an instrument cluster warning light fail in more than 45 years of motoring but I was delighted to find that it had. Another quick visit to Halford to buy a £2 replacement and now all seems well. I've yet to fill the tank to check that the light goes out beyond the 4l reserve.

Fingers crossed, problem solved.

tachoD
Forum User
Posts: 8
Joined: Tue Jun 20, 2017 1:37 pm
Country of Residence: United Kingdom
Location: Norfolk

Re: Low Fuel Light Not Working

Postby tachoD » Sat Aug 12, 2017 2:00 pm

Hi, and welcome to the forum, I'm new here also with a 04 Gs. My first reaction would be to change the bulb. Mine had two dash bulbs go on the speedo and reading the replies of the members in the F650 forum these do fail. Getting to them is a bit lengthy and fidly but not a difficult job. Others recommend changing all the bulbs to LED as they last much longer which I will do next. For the instruments you will have a choice of blue, green red, etc and for the warning lights choose the appropriate colour LED not white.

tachoD
Forum User
Posts: 8
Joined: Tue Jun 20, 2017 1:37 pm
Country of Residence: United Kingdom
Location: Norfolk

Re: Low Fuel Light Not Working

Postby tachoD » Sat Aug 12, 2017 2:02 pm

Hi, and welcome to the forum, I'm new here also with a 04 Gs. My first reaction would be to change the bulb. Mine had two dash bulbs go on the speedo and reading the replies of the members in the F650 forum these do fail. Getting to them is a bit lengthy and fidly but not a difficult job. Others recommend changing all the bulbs to LED as they last much longer which I will do next. For the instruments you will have a choice of blue, green red, etc and for the warning lights choose the appropriate colour LED not white.


Return to “F Series Technical Q&A's”

Who is online

Users browsing this forum: No registered users and 1 guest