Erratic fuel gauge, 2006 GSA

Here's the latest

Reading on the range said 5 miles and still going so thought it best to fill to the top and see where we are.

Only got 22 litres in
I guess if they have been fiddling around changing this and that it could be a tad confused so a fill up should settle things down.


Have reset the trip and now I'll ride and see what happens next.

To be continued................

Dealer said fuel pump controller was bad(replaced once under a recall in US). They say it's fixed, but I'll see when I pick it up on Tuesday....I'll let you know.

Joe

I'm usually an optimist . But!!:

Joe, I'm sure someone else replaced the FPC, with no luck? (Might have been bwallis42 on AdvRider).

And Tony, I had a similar feeling that the system might have got confused after I changed my SJP, so filled to the brim and hoped it'd gone away...... 22 litres doesn't sound good Be interesting to hear what they HAVE replaced. In particular, the Pressure Regulator? Flange? Pump?

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IanC said:

Joe, I'm sure someone else replaced the FPC, with no luck? (Might have been bwallis42 on AdvRider).

Click to expand...

Yes, 'twas me. (I'm here as well like most of us

Made no difference to the fuel transfer (I didn't really expect that it would).

I like the theory about the built in filter being somewhat blocked.

I had the pump out yesterday having a look at where the fuel filter is and to have a think about how it might come apart but no luck. It looks like it should come apart but it isn't obvious how. Didn't want to break my only one trying!

bwallis42 said:

Yes, 'twas me. (I'm here as well like most of us

Made no difference to the fuel transfer (I didn't really expect that it would).

I like the theory about the built in filter being somewhat blocked.

I had the pump out yesterday having a look at where the fuel filter is and to have a think about how it might come apart but no luck. It looks like it should come apart but it isn't obvious how. Didn't want to break my only one trying!

Click to expand...

My bike did the running out of fuel thing with 4 gal left in the tank, but then died completely with the fuel pump not working at all. Could be that the controller just failed and it's totally unrelated to the transfer problem, or it was wonky all along and ran the pump at a voltage high enough to run the engine but not enough return fuel flow to run jet pump

I'm going to ride in (with a full gas can in the panner) until fuel light comes on and see what happens.

Joe

Tony, any news? What did your dealer do?

It was suggested to me today by a guy, knowledgeable/experienced who owns an independent VW garage and also rides a 1200GS, to clean out the pressure regulator - so think I'll give that a try!

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Update!!

Got bike back from dealer and it seems to run fine. The fuel pump controller plug that plugs into the fuel flange was corroded because of a pinched "O" ring that was replace under a US recall by another dealer.

I ran the bike 340 miles until range to go said 70 miles. I took 7.3 us gallons (27.6 liters) to fill up, which leaves about 1.7 gallons still in the tank. It was still running fine (last time it ran out of fuel at 250 miles). Looks like the numbers come out close enough (46-48-MPG)

In my case it looks like the corrosion on the connector cause enough of a voltage drop to slow the pump down enough where it would run the engine, but not return enough fuel to operate the transfer pump (sucking jet pump)





Now the fun part is trying to get the original dealer to make good on his screw up as his mistake cost me $308.00 plus the excitement of engine dieing in traffic at 70mph! (yes I know, good luck with that!!)

This worked for me, I hope it may help others.

Thanks,
Joe

Joe, I sincerely hope you've sorted it! I'd feel happier though if you'd filled up with 30 litres I must admit.... You're getting very good fuel economy!

I got my Fuel Pressure Regulator out yesterday, hoping to find it full of muck, but sadly clear as a bell . But gave it a good air-blast together with all four pipes. Not an easy job, certainly on an ABS bike - very tightly jammed between the airbox and ABS pump.

But I did chat to guy at BMW dealer who said they'd had a bulletin saying that a number of customers have reported our problem - the recommendation was to replace the "entire fuel pump assembly" - presumably they mean the flange + pump. I didn't get full details as couldn't speak long, but will try to find out more (after checking corroded connector as Joe describes). And he may have an old pump I can try....


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Rubbish?

I have no idea how the hardware is laid out, however another possible cause could be...

If the suction and return lines were swapped over on this pump that pushes fuel from one side to the other.

If it was sucking out of the side the engine uses and rather than delivering it to that side.

While the tank is quite full it will suck from that side and flow back again, but at some point the side it should be sucking from will stop over flowing back into the engine delivery side, but be full.

I am not even sure if it is possible to get the lines mixed up or the pump put in the wrong way round.

There is, of course, the distinct possibility that I am talking rubbish.

Gareth

Hi all

Back to the dealer tomorrow to pick up, as promised, a "hopefully" detailed list of everything that has been done to my bike.

I've been busy so not been able to use up all my fuel yet to see if the problem persists.
I'll pull my finger out this week.

Cheers

Agrajag said:

I am not even sure if it is possible to get the lines mixed up or the pump put in the wrong way round.

There is, of course, the distinct possibility that I am talking rubbish.

Gareth

Click to expand...

Gareth, thanks for the suggestion, but no, it's not really possible as the "pump" is submersible, i.e. only has a delivery hose, no suction house. And can't be on the wrong side as its solid-fixed to a flange.

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Hi

Had some time today so went for a ride to use up the fuel and see how things went.

Out for a wet couple of hours when the fuel light came on at 44miles.
Sounds about right. Now it usually stops just after that.
Under 30 miles range and still going so I'm thinking it may be sorted.
Head for my dealer to give them the news.
Can you believe it "ran out", stopped, range 25miles right at the door of the dealer!!!!!!!!!!!!!
I left it where it stopped and went in

Had to move it for a car to get through after 5mins, wouldn't start, normal, tipped it over a couple of times, away it went.

So now they don't know what to do.
They have spent all the time and money they are allowed to trying to sort it under warranty and to carry on they need some top BMW chap to come and deal with it.

I went to fill up and report back to them how much fuel I got in.
28 litres. So 5 litres shy of the 33l.
So 50 miles really.
Now to me that isn't running out of fuel.


I have a couple of invoices from the last two visits.

Fuel-level sensor, replaced. part £64 Twice this was done.
Control unit, replaced. part £297.50
Remove fuel tank and replace with one from another bike. Problem the same!
Instrument cluster, replaced. part £483
Fuel pump was also changed but original was put back when there wasn't any improvement.
All plus labour of course.

They do seem to be trying don't you think

I was shocked that swapping the tanks didn't sort it, I felt sure it would as the tanks holds so many of the parts that it could be!!

So, I'm all out of ideas.

Hope you lads are having better results.

Maybe I'll go test ride an Explorer

Cheers
Tony

Well Tony, I guess at least we're eliminating the possibilities! So are they going to get Mr BMW down to take a look? Surely if he can't sort it he'll have to ask the factory?

As I mentioned in an earlier post, a couple of days ago I had the Pressure Regulator off (which your dealer doesn't appear to have?). Wasn't dirty, but I wonder if that could still be it? Otherwise, I can only see it can be an electronics problem, or the actual fuel lines?

I have also now removed my Fuel Pump Controller, as Joe mentioned, and cleaned the plug but it was bone dry and squeaky clean so I don't think I've done any good

But I guess it's only fair to ride til it stops again, having tried two new things!


BTW, was the "Control Unit" the Electronic Fuel Pump Controller, or the main Top Flange? And was the Fuel Pump the Flange + Pump, or just the pump? But I guess it's immaterial if replacing the whole tank did no good. Silly question, but are they sure the replacement tank worked correctly? I could imagine some people being blissfully unaware and settling for a 28 litre fill-up!

I'm going to quiz my dealer again tomorrow about the bulletin he had.

Ian,

Got a call today from my old dealer (Mortons BMW) in Virginia 600 miles north of where I live now. I had asked him about my fuel problems on a visit up north last week. He called to say he had just received a notice from BMW North America concerning the very problem we have been having.

Their conclusion was that the fuel pump is not pumping the proper volume of fuel thus causing the sucking jet pump not to operate properly. The recommendation is to replace the fuel pump. In my case, because of the corrosion of the connections on the fuel pump controller, it caused the same problem. Try an aftermarket pump:
http://www.euromotoelectrics.com/product-p/fp-379.htm
or oem.

As far as Brown Dog's problem, after they replaced the whole tank assembly, I can't imagine what is going on.



I hope this works for you,

Joe

Joe, that must be the same bulletin my dealer was taking about, I'm going to have a word with him.

Tony, on further thoughts, the only way your complete tank could be proven "innocent" is if they tried it on another bike, e.g. the one they'd taken the tank assembly off of. It's a shame they didn't do so.

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Hi Ian,

My dealer said they would be contacting this BMW technical guy straight away but as he covers the whole of the British Isles they don't know when he would arrive. One busy man I would say!
They are also aware that I'm of to Morocco on the 16th May so really could do with it being sorted before then.

I was annoyed at their suggestion that the fuel gauge will never read 0 miles range as its worked out on an average and that I could be changing my riding style
All the bikes they have given me as loan bikes are always low on fuel and everyone of them I have returned in single figures on the range as I live near without any problems at all.

Doesn't look like they changed the pressure regulator but I'm sure they checked the pressure as they had suggested this could be the problem.

Not sure if the flange was changed when they did the pump but as you say, swapping tanks should have eliminated these parts.
The tank was from a brand new bike in the show room.
I'm sure they didn't try my tank on the other bike, but I see what you mean, that would have been a better way of doing it.

The thing is, erratic fuel gauges I'm used to having on all my bikes. Fill up, reset trip, away you go. You know, if it runs out of fuel, its empty, and you're going nowhere.
Now just getting back to the basic problem we have:
Our bikes aren't running out.
Just a simple shake of the bike gets it on its way for a few miles, and then again and again when it stops. Its so strange
Approx 300 miles to a tank is about what I'm getting before it stops, leaving around 5 litres still in the tank when I do fill up.
Now that would be fine, fill up, set trip, 300 miles you then know you have approx 50miles to get some more fuel.
But that isn't what's happening.
By the way, my MPG says 49.6 for that tank full. A real mixture of riding.

They talked of a unit that controls all the electronics that go through the bike, and looking at the price of the control unit changed I'd say it wasn't the fuel pump control unit on top of the flange.
When I asked about the fuel pump controller they said it was just a fancy relay that would either work or not.

Cheers
Tony

Ian,

Just checked the part numbers for the control unit that was changed:



01 61 35 8 521 877 CENTRAL VEHICLE ELECTRONICS 1.26 1 $645.29

greetings from Greece...

Hi to all u-having the same `dammned` fuel gauge-problem.Being reading since the very start of this thread and must say,my shelf and many more 1200gs/gsa riders from Greece having the same issues.So, my point is,imo that the real problem maybe lays upon the `fact`,that none of the fuel gauges at the lcd screen,nor the fuel level strip,not even the fuel pump are responsible for the faulty readings.What i belive is that we have to solve an equation that consists of these facts;fuel that is returning,pressure regulator(rates and quantities/time or rpm..?)and finally when-this litlle crappy pump that is supposed to tranfer fuel between the two fuel tank compartments-works,what is its fuel flow rate/main fuel pump flow rate.If we knew when it starts working(below what level)and how much fuel tranfers(is it working by a steady rate of flow or not..?),and what fuel flow our main pump has(min-max),maybe then,we could determine why all these shit are happening

Tony - well I'm very pleased replacing the 'CENTRAL VEHICLE ELECTRONICS' didn't fix it!!

My suspicion about the Pressure Regulator is more that it might be somehow restricting flow on the return line rather than delivering incorrect pressure - after all the bikes are running fine. Not that I understand how it works exactly (not a complex part though) - more that I can't think what else can be left now!

Stukas - I did some measuremenst a while back, and hadn't realised I posted the results only on AdvRider. But I quote myself:

"I took some measurements with my old SJP (which I've now no reason to think is faulty) in a bucket of water with roughly the same head/lift as on the bike. Conclusion: I reckon you need in excess of 500cc/min flow to make the venturi actually EMPTY whatever it is submerged in, as opposed to fill it up. Say 600cc to be safe.

So I measured the flow on the return fuel line on the bike - it's about 250cc/min at tickover. Not sure how this changes with revs, but may well be less as don't forget this is the leftovers from the injectors. But the Fuel Pump Controller may try to keep this constant?"

Hi Ian

I have good news

My bike is fixed!

I hope its not to early to celebrate

I'll start with saying that you were right

My bike went back in on Tuesday last week.
My dealer called some top BMW guy who listened to what had gone on with my bike and suggested a new fuel pump was fitted
AND a fuel pressure regulator!!
I had my back back whilst they waited for parts!
Now a fuel pump had been tried, as had a whole tank assembly, but the regulator was a new one for them.
You have said this all along, and I had passed on your concerns about pressure/flow through the venturi pump which made a lot of sense.
Returned the bike Friday for parts to be fitted.
On collection they were pretty sure it was sorted.
They took a measurement before, which was 130!
130 what the young lady couldn't tell me but I'm guessing cc, as its only a 4bar reg so its not psi, must be flow.
She said the min requirement was 180 and after the new parts were fitted the reading was 400!

I know how much fuel I had in the bike and what mileage I should get and so far its bang on
10 mile range left showing. (I've been carrying a can of fuel)
Tomorrow I'll fill up and I'm expecting to get in around 33litres.

So a new regulator approx £50 and at a push a new pump, what around £250
should do it

How are you getting on?

Cheers
Tone