Low Fuel Light Problem....Please Help

[colewj]

In short the problem is:

* "The bike" went in to the shop because it's engine had stopped.
* Hose from fuel pump was reconnected
* "The bike now runs fine BUT the low fuel light is now constantly 'ON'.


I'm hoping the collective knowledge of all the riders on the forum will have a solution as the constant orange light is getting old.
Here's what happened.
Long Version:
The patient, "The bike", is a 2003 R1150R with just under 18,950 on the clock.
6/24/2010
Back at the end of June the following services were done: Fuel filter,Rear brakes,Valves adjusted and injectors balanced,Fluids (all) changed,Tires replaced, New York State Inspection.
Life is Good
7/07/2010
Two weeks later "The bike" quit on my way to work.
The engine just quit. Period. It felt like hitting the kill switch or turning off the ignition.
Once I got to the side of the road and began to figure out what the problem was the only thing out of the ordinary was a strange noise from the fuel pump and the fact that "The bike" would not start.
Just in case "The bike" was out of gas and the low fuel light had failed, my daughter, who came to my aid, brought gas which I added.I didn't think this was the case because when "The bike" quit it was immediate. It was not the same sensation as running out of gas which happened a few years ago.
I went back in the evening with a trailer, picked up "The bike" and took it to the shop.
7/08/2010
Good news:
The word was that "The bike" had quit because the hose from the fuel pump to the fuel filter had come off the pump. That was also the reason for the strange noise from the fuel pump.
This hose had not been removed from the pump two weeks previously when the fuel filter was replaced.
The hose was securely put back where it belongs (and Life is Good).
Not !
Bad news:
The problem, I was told, was that now the low fuel light had come on and would not go out.
The shop had removed and replaced the tank 3 or 4 times and they could not get the light to go out.
They asked if the low fuel light had been on when "The bike" quit. It had not. In fact gas was added after "The bike " quit.
The low fuel light has functioned normally for the approx. 18,800 miles that I've owned "The bike".
All wires were checked. The underside of the tank and flange were checked for damage that may have occurred while removing/replacing the tank etc. and no damage was detected.
They plan to look into what may be another cause and get back to me, but they figure that the low fuel sending unit is bad.
I've been looking at the orange light ever since.
To the best of my knowledge the low fuel sending unit is not available separately. From BMW it's $400 +, from The Boneyard it's $200+ since I'll have to buy the flange and fuel pump.
I found one that a fellow member had posted for sale which had a bad flange but someone else had been interested and he was waiting for payment.Eventually the guy came up with the $40.The member said he would try to contact the guy to see if (hopefully) the guy does not need the low fuel sending unit so there's still hope from that source.(I'm keeping my fingers crossed, consulting the spirits, and have retained the services of a Voodoo witch doctor.)
I've had suggestions that I pull the relay, pull the bulb, or tape over the bulb and just use the odometer
I'm fine with using the odometer but I'd really like to get the cause taken care of.
I'll be most grateful for some help.
Thanks, Bill
P.S.
CycleRob, I hope that's enough info/history. If not, let me know what else you figure might help.

[boxermania]

The problem is with the repair shop....

1) The hose for in tank service is SAE 30R10 as it will not swell up.....SAE 30R9 is for outside service
2) What clamps did the Tech use, compression (Sic) or the FI banded type
3) The wrong hose or the wrong clamp will lead to your failure....or sloppy workmanship

The reserve light is nothing more than a float and a micro switch, so during the last repair the Tech either bent the float arm, damaged the micro switch or shorted the wire from the microswitch. In any event the issue lies with who serviced the bike, take it back and insist they correct the problem......based on your experience, the repair shop is questionable.

[keithbw]

In my '02 for the low fuel light sensor is just a small canister with a float inside. The plastic canister just clicks into detentes(?) in brackets mounted on the fuel pump mounting assembly. It has an adjustment range of about 3/4 of an inch or so, and can be knocked off (or maybe broken) when reinstalling the pump assembly back into the tank. Or maybe the float is stuck inside the little canister.

Anyway, I had the same problem and it was because the little canister had come loose from it's mounting bracket.

Regardless, as boxermania noted, the shop should have figured out the problem before three tries.

[CycleRob]

colewj, Your info/history was superb! The correct responses you got from boxermania and keithbw were much better for everyone than those PMs between us.

Obviously, some damage has occurred to the low fuel light switch assembly or it's wiring during the service deptment's R&R. It's a mystery why a BMW shop cannot isolate the short or repair it. A savvy teenager with an Ohmmeter could find it quick. It should have set off their internal fault alarms when a fuel heavy gas tank immediately shows a low fuel light after the fuel pump plate was removed and reinstalled. Looks like the servicing shop should fix the problem they created.

The LFL switch assembly is a simple component that may have a simple fixable fault, so I wouldn't rush to judgment with the used replacement.

.

[boxermania]

I would like to add that removal of the pump/filter unit from the tank is a delicate operation as you have to move it about to get it out......if not careful, damage can take place during removal or installation.

[dnat928]

Sounds like very poor trouble shooting logic at the shop. Since the hose at the pump came off, that gives a poor indication of their mechanic skills. It's way too suspicious that their work on the pump and hose - with the fuel level sensor as a part of that assembly - suddenly went bad. Face it, and make them face it - they goofed up the sending unit. For the low fuel light to be "ON", the float is stuck in the down position...or the wiring got tweaked to give a simulated "down" position.

First easy check...unplug the connector under the gas tank that carries the fuel level signal. The light should go off. If it doesn't...it's the relay. If the light goes off...the problem is in the tank...a stuck float or it's the wiring. (a down float makes an electrical connection...if the wiring has been tweaked, it may be shorting outside the float tube to give a connection - a low fuel signal).

[WorkinMan]

For what this information is worth... When I bought my 2004 a year ago, the man gave me a complete fuel pump/fuel filter assembly with the bike. He told me that the low fuel light came on and stayed on, (With less than 3500 miles on it) and that BMW said it was not servicable. He had to pay them to replace the entire assembly. The bill, including labor, was somewhere in the neighborhood of $500. So GOOD LUCK getting your shop to admit that they screwed something up and getting them to eat the bill for it. If you find a way to fix it, let me know, as I have a perfectly good assembly hanging on the wall that just shows a low fuel light all the time.
Chris