'06 1200GS cutting out (but not the same as the other thread)

sr1

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Gents, new here. I fought this battle with the bike and and worked with the ADV guys, but apparently didn't solve my issue. I'm expanding my search to other forums such as this, I hope someone can help me out.

My saga is all recorded here: http://www.advrider.com/forums/showthread.php?t=773896

but here's the update, as of today (after receiving the bike here in Korea, from the US):
-----
Well, after the bike has sat in a shipyard in a connex for 3 weeks, then spent 6 weeks on the Pacific ocean, I am sad to say that the bike is exhibiting the same issues as before.

This could be interpreted as meaning that it was indeed water in the system somewhere and the jostling shook it out...


Or???

I really don't know what to do next. I'll give you all a rundown of all that I've done, in chronological order, but first, a brief review of the issue itself:

Bike exhibits severe "cutouts" in power on hard acceleration. All gears. No clutch slippage. No engine stalls.

More and louder backfires, especially on deceleration.

Issue seemed to have started immediately after a fuel fill-up, but cannot be defined as the culprit - I had just returned to the bike after 7 months out of country, AND it was my first ride with the bike. Still, I didn't feel the jerking and cutting out until that fill-up.


What I've done, in order:

Drained tank and replaced with known good gas.

Used Seafoam, and later a bit of alcohol, in the gas to dry it out.

Pulled each coil wire (separately) and rode the bike. The coil wire with the least affect on the bike's running was Left Secondary. Inconclusive though.

Took the bike to BMW, they didn't find a thing other than a "low voltage" on the fuel pump electronics. A few hundred $$ later, I still had the same issue, even on the way home from the dealer.

Bought and replaced BOTH secondary coils.

Finally, I changed the spark plugs. The left secondary was fouled. Immediately upon changing them, the bike felt like new.

Three days after changing the plugs, I put the bike into a connex for shipment here. Now I have the same problem again.


Strangely, it seems as though the problem gets "better" over time, but never goes away.

Ideas?
 
It's the fuel

If you are sure this occurred after a refuel, then the fuel is at fault. Don't run the engine with coils disconnected the unburnt fuel will damage the catalytic converter!
It's not uncommon to have water in the fuel, and will always seperate and drop to the bottom of the tank, just where the pickup is. I would remove the tank empty and dry out completely, replace fuel filter, rebuild and refill with the best quality fuel you can find, not supermarket/cheap fuel. :comfort
 
I just can't be sure...I wish I could. Yes, it occurred right after a re-fuel, but the following factors were in play that day:

I'd not ridden the bike in 7 months prior (it had ran perfectly at that time)...oh, for the record, the bike was stored with fuel stabilizer.
I was 2-up with my wife and probably taking it easy
I had only ridden about 20 minutes
Simultaneous with the re-fuel, my wife (again) complained about a painful helmet (she is Asian and every helmet I've bought her hurts) so I turned around and headed home. Probably in frustration and desire to get her home, I gave it the berries a bit more. That's when I felt it.

So, the possibility of this existing prior to the re-fuel is there. Doubt about this is definitely playing a part.


So, IF it were the fuel (and I still lean toward that in my mind...I really do), I need to replace the fuel filter? I'm not familiar with what the GS filter looks like, most are "canisters" so to speak and if you get water in the line, you'll see it all in the filter. Same with the GS? I gotta look at a parts fische and see where it is. arghhhhhh
 
Reference http://www.ukgser.com/forums/showthread.php?t=202932

There is no "filter" that is separate. There is a "strainer" and that's it. Now what? I don't think (there I go thinking again, that's what gets me in trouble every time) that there's a need to replace a "strainer" and the pump. I did drain the tank as soon as I got home, though...

I would take my bike to the Seoul BMW shop and just give them my high limit credit card, but the last dealer that looked at my bike freaked because the first owner put in hard fuel lines and a line for an external fuel tank. I gotta do it myself, either way.
 
Have a look at what the Throttle Position Indicator (TPS) is up to. For some reason faults with it don't always show on the official test gear.

The TPS could give those symptons, it's not that common a fault but I've had it.
 
I was under the impression the TPS only would do that just off-idle. If anything, that is a portion of the throttle I NEVER get this symptom. The symptom is ALWAYS exhibited under hard, and I mean HARD acceleration, while underway (said another way, the symptom does not occur under any condition immediately off-idle...it always occurs when I am just breaking "go to jail" speed and accelerating-the throttle is open and I am cruising along fine...then I accelerate hard...it starts to accelerate then coughs and stumbles its way to the new RPM). Could the TPS still be suspect?

If so, how do I troubleshoot it?
 
sr1 said:
I was under the impression the TPS only would do that just off-idle. If anything, that is a portion of the throttle I NEVER get this symptom. The symptom is ALWAYS exhibited under hard, and I mean HARD acceleration, while underway (said another way, the symptom does not occur under any condition immediately off-idle...it always occurs when I am just breaking "go to jail" speed and accelerating-the throttle is open and I am cruising along fine...then I accelerate hard...it starts to accelerate then coughs and stumbles its way to the new RPM). Could the TPS still be suspect?

If so, how do I troubleshoot it?
Click to expand...

What the French dealer did with mine was to take the TPS off a showroom bike, this was after 5 hours trouble shooting, the fault didn't show on the test rig. The French techies insisted it was bad fuel for the first couple of hours, drained the tank/lines etc

Mine would not idle and had to be held around 3/4 rpm just to get underway.
Sorry, I can't help you more
 
Try the colis again.....

Disconnect 3 of the coils at a time. The bike will start on 1 working coil. Do not ride the bike. If it starts it tends to mean the coil is OK. Repeat on all 4 coils.

When you have found the suspect swap it left to right so you can determine that the spark plug and wiring and not the issue.

Cutting out and hesistating when under load tends to be a dead/dying coil most of the time.
 
Alex,
Will do. I have a job function both Wed and Thurs nights, so I'll try this Friday night and report back.

Shall I try to rev it with only one coil if all positions start?
 
I would not rev it as you will dumping unburnt fuel through the other cylinder. See if it starts, and then turn it off.

This process has worked every time when there is a dodgy coil.

There could be other reasons but this will allow you to exclude coil packs, spark plugs and wiring.

Good luck


Alex
 
Could your fuel pump controller be developing a fault and intermittently failing??

Mine failed and caused a few cut outs before completely failing. :mad:

Not too expensive to change (£40 approx) and could eliminate this possibility.
:nenau
Good Luck.
 
Alex, ok, will do.

Clive, (in the ADV thread) the BMW dealer that looked at the bike replaced the fuel pump "electronics" and the symptom existed before and after said replacement.
 
Fish the plug that was fouled out again and see if it is the same as before. If it is then at least you have isolated a side. Going from there I would swap the lambda sensor from one side to the other and see if the fowled plug moves sides. I would also suspect the coil on that plug if it doesn't swap sides.

Getting back to the fuel, it is possible that contaminated fuel could have contaminated your injector. Cleaning tanks and lines wont help this situation. Some injector cleaner in the fuel might help though. Its difficult to recommend this because of the danger but it is possible to remove the injector but still be connected. Turn the engine over and watch the fuel spray. It should be nice and even with no drips or squirts. Again this can be really dangerous to do and should actually be done on a test rig with a none explosive testing liquid.
 
Tried starting the bike tonight on one coil at a time...started and ran fine on all (at idle).

I have another test to perform tomorrow, and will also check the plug for fouling.
 
I know nothing about bikes as complex as 1200GSs.

However...

A bike that cuts out when given the berries, and for which the symptoms get worse when the tank is full*, to me points to a good old blocked fuel tank breather.

*When a tank's full, there's less air above the fuel within which a vacuum can occur, so it makes the symptoms appear more quickly.

Ride it hard until the symptoms occur, then pop the filler cap. See whether you hear air rushing in, and whether the problem cures itself on re-starting.

It's an easy check, so has to be worth ruling out.

Paul G
 
results from a test performed this morning...also reported on ADV...


I rode the bike this morning until the oil cooler was quite hot to the touch and I could not keep my finger on it any time. Not having a proper thermometer, this was my gauge for oil temp of 180*. I think I got the appropriate results, but I have no idea where to go now, that's what you guys are for. ;)

Results:

With primary coils plugged in and no secondary coils, the bike exhibited mostly the same symptom, to a slightly greater degree. Jerkiness was greater, as was backfiring and idling was rougher. However, it was not *appreciably* greater (in comparison to what happened next). Basically, in this configuration, I would say 20% change for the worse. FYI, all RPMs could be reached.

With the secondary coils plugged in and primaries not in use, the bike nearly refused to accelerate at all. When accelerating at a tame "downtown" rate it did ok (but rough) but the moment I added any throttle at all that wasn't completely smoooooth, it would feel as if the brakes were applied full stop. No power whatsoever and nearly launched me over the bars a few times it was so violent. This was all under 3500rpm. I didn't even try to get over that, it was about all she'd do to get to 3500...at the rate I had to open the throttle, it would have taken 10 minutes to get up to 7000 rpm.

So, I reckon that points to the secondary coils. But I've already replaced them, just in April (with no appreciable improvement), don't forget. What's next?

Two questions on the side: I was going to check the plugs again, I expect the left secondary to be fouled again. Can I just clean it, or is it trash?

On the test of switching the Lambda sensors and see if the fouling follows, is this a good test at this time or down the wrong direction, considering the results of the above test?

JVB on ADV is recommending I repeat the test with a spark plug swap, pending clarification on his preferred swap procedure now...I'll probably repeat the test either later today or tomorrow am, unless he wants me to swap the plugs altogether (which will take a while to receive). After that, he also nods toward Lambda sensors, so that may be tomorrow's test...we'll see.

Any other ideas? (on the fuel return line possibility, it is a simple enough test, and I'll try it ,but all tests so far point to secondary coils and/or left side ignition of some type.) I am always happy to try another test...this is driving me nuts.
 
Your bike will always run like crap on the secondary coils only so I wouldn't be too concerned about that. It runs on them alone which is I think as good as you can expect. I would still swap over the lambda sensors and see if the fouling moves sides, after you have cleaned the plug of course.
 
From my post on ADV:

This morning, following Jim's direction, I swapped plugs top to bottom (on both sides of course). The secondary plugs did look a little fouled, but not significantly. Appeared to be equal on both sides (maybe that's important?)

Rode the bike to the test area, allowing it to warm up. All along the way, the bike performed about 5% better than with the plugs in the other position, but that's probably due to the light fouling...still exhibiting the same problem overall.

So, once the bike was up to temp and I was at my test area (about a mile straight without traffic, out amongst the rice paddies) I tested the bike again.

Results were identical to yesterday.

Primaries only = performance about 20% less than with all coils.

Secondaries only = Bike tried to buck me off, would not accelerate normally...nearly "unridable" unless I just HAD to get home.

Oh, for those that suggested fuel cap and spark plug nut tightness, I tested both...nuttin'.

So, what's next? Do I swap the Lambdas? What am I looking for when I do that? Or, just replace them both? Or???

Thanks all for your patience, looking forward to the next portion, and the solution. __________________
 
Hmmm my idea of swapping the lambda sensors over was based on only one secondary plug being fouled. It's seems both are the same though so it's probably not worth he effort.
Do you know anyone with a GS911? The only way I can see forward from here is to get some live sensor data but you will need a 911 for that. With the data from that it should be pretty easy to pick out what the problem is. You could carry on the way your going but it will take ages and at some point your going to have to swap in known good or new components.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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