Fuelling problem?

Philsilva

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Hi all

Just wondering if anyone out there can help me out on an issue I've got.

I recently bought my wonderful 08 GS and then quite soon had the fuel sensor die on me but had it in warranty from the previous owner so duly took it to Pidcocks BMW Long Eaton who fixed it for me.

5 weeks later the sensor died again and I went back to Pidcocks to see if they could help and they agreed so again I took it to them and after a couple of days I picked it up all fixed :bounce1

Unfortunately when I got it home it started to leak fuel. I called out recovery in case it was a quick fix but they couldn't help as it was nothing they could deal with at the roadside and as it was end of play Saturday I couldn't get hold of Pidcocks until Monday when they agreed to pick it up and fix it......turned out to be a worn fuel o ring.

Happily I took back my P&J a couple of days later and waved the van driver off with a big smile on my face :)

So........to bring the story up to date..........When using the bike back and forth to work recently it has been very lumpy, smelling of fuel at lights and such (initially put this down to the remanants of the previous fuel leak) and has also been prone to stalling at very slow speed in either second or first gears. There is also a significant build up of soot on the tail pipe.

The questions are: (sorry to drone on so...)
1. what do you think the issue is
and
2. do I go back to Pidcocks with it? Can't say I'm too keen to take it back...god knows what they will do to it next!!

Any replies greatly appreciated :thumb
I await the outpouring of your boundless knowledge and experience oh great owners of the GS :bow:bow:bow
 
Sounds like it's over fueling and running very rich. You do need to return to Pidcocks; i reckon as they will tell you
very quickly what the problem is.
 
Sounds like it's over fuelling or not firing prooerly on one/both cylinders which is then wrecking the Lambda sensor.
Send it back, they need to get to the root of the problem not just keep fitting new lambda sensor

Sent from my SM-A320FL using Tapatalk
 
Fuel Sensor?? Fuel level gauge sensor???

Sounds like a dodgy Throttle Position Sensor, basically the T.P.S. tells the ECU that the throttle is @ x% open and the fuelling is adjusted to suit

If its off and say that the throttle is at tickover, but the value that the ECU receives tells it that its at 1/4 throttle it will get fuel for 1/4 throttle!

That's guess work from a distance with what info I have available As far as the fuel sensor goes they are complete schite learn to use the trip meter
 
There might be more than one problem.

Under normal conditions the spark plug fires every time it's needed so the fuel is burnt. The O2 sensor tells the ECU to add more or less fuel as needed to keep the correct mixture.

When a coil misfires the unused oxygen causes the ECU to add more fuel. So the fuel which does get fired burns very rich. The unburnt fuel leaves the exhaust gas full of unused oxygen. Result is sooted up spark plug and O2 sensor. The Hexhead is effectively two single cylinder engines so this problem can affect just one side. Swap the primary coils left and right. If the misfire moves you've proved its a coil. If both coils are failing the only reliable test is to try a pair of good ones.

Another possibility.
When the fuel tank cover is removed (to fit the fuel strip sensor) the rubber seal is very easy to dislodge. It will leak like a sieve when you fill the tank but can seem perfectly fine when the fuel level is below the gasket level. When re-fitting my fuel pump, I make sure the gasket is dry on the outside. The inside face of the seal and fuel pump body are both greased. This allows the pump to fit easily without dislodging the gasket. Pidcocks should know this. Maybe the mechanic has rushed the job.

Another time, you might want to talk to Mikey over in Rutland.

The fuel strip is rubbish so even though its covered by warranty you can expect to be going back regularly until the warranty runs out. There is another thread about fitting a float gauge.
 
Well thanks everyone for your help and thoughts..

I think I'll get it back to Pidcocks and see what they want to do with it. As has been said I guess we need to get to the bottom of the issue ASAP.

Thanks Bendy Toy I'll have a look at the float gauge for the future as I get the feeling i'll be a regular visitor to Pidcocks in the immediate future :)
 
The fuel strips have no moving parts so should be great. Somehow BMW have screwed up and they don't last 5 minutes.
The mod uses the later model float sender with an adapter. It's a work in progress.
 
Well Pidcocks have confirmed that it was a duff lambda sensor so thanks everyone for your support. I'll ask about 'cause' when I get to pick it up. 👍
 
I got conned into fitting a new Lambda sensor (though not by Piddies). It was ok for a while but soon sooted up just the same.

Mine was failing coils which don't show on the test computer (or GS-911). The symptom of faulty O2 sensor does show however. It's faulty due to over fueling, caused by misfiring coil.
 
Bendy toy said:
I got conned into fitting a new Lambda sensor (though not by Piddies). It was ok for a while but soon sooted up just the same.

Mine was failing coils which don't show on the test computer (or GS-911). The symptom of faulty O2 sensor does show however. It's faulty due to over fueling, caused by misfiring coil.
Click to expand...

Hi Bendy toy. Thanks for the input. Should they be looking for this when they do their tests? Is there a way to pick it up before they default to the sensor? Just concerned that the same thing might be happening to me which may be impacting on the fuel strip as well?
 
My primary coils were both misfiring making fault diagnosis very hard.
They both smelled of hot insulation but until they totally packed up I'd not spotted it as a clue.
Easiest test is to try a pair of known good primary coils. If performance improves you have the culprits.
Don't buy coils just in case - at £80 each it's a way to go bust pretty quickly.
The fault code examiner has no codes for coil faults so you have to look at other symptoms. Lambdas will soot up but if it's a coil they become the symptoms not the cause.
It's worse when hot.
Another potential is the crank sensor on top of engine. They can play up when hot but be fine when cold. Again the ECU will not show a fault.
 
Just replaced both lower coils on mine at 43,000 miles. What a difference, the bike is now much smoother and more responsive. Lower right coil was delaminating, new coils appear to be plated or fitted with a stainless jacket.
 
My secondaries must be on the way out. But I don't fancy BMW price replacements. I'm planning on using a pair of car engine stick coils with patch leads to the connectors and HT leads to the plugs.
 
Mine were £79 each from m&p, slightly different angle to the originals but the LT wiring reaches okay.

Performance improvement was very noticeable on this mornings commute. :D
 
Interesting. My bike has never been especially smooth and always a bit fluffy at low revs.
The secondary plugs always look as they should but maybe the coils are (always have been maybe?) suspect.
 
Bendy toy said:
Interesting. My bike has never been especially smooth and always a bit fluffy at low revs.
The secondary plugs always look as they should but maybe the coils are (always have been maybe?) suspect.
Click to expand...

Exactly the symptoms I had bendy. Replacing the lower coils has made an amazing difference, todays commute seemed even smoother and more responsive on opening a closed or feathered throttle.
 
More wedge to spend :(

I'll pop into my local car parts factors and check out some three wire stick coils.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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