New Tosser with misfire....

[Steve Robinson]

I've come straight here from introducing myself.

I got a big problem with intermittent misfire which is threatening to break me and my GS up....

Purchased privately in October 2016 - did a couple hundred miles and put it away for winter (fair weather biker).

Noticed misfire first time out this year in April - evidenced after 40-60 miles running and gets progressively worse. No fault codes, BMW can't find fault so told me to go away until it gets worse. It gets worse but they don't take it on 60 mile tests. (Full BMW service history).

Damien at at Daytuner Performance near Harrogate (used to build/tune my bike race engines) diagnosed injector down 20%... sonic bath and it ran like a dream for 800 miles - round IOM. Then started misfiring again - progressively getting worse over time and evidencing itself over shorter distances.

Trouble is it just won't do it when I got somebody with me who understands these things. Bike is with Damien now, I know he will fix it in the end but really looking for a short cut... off to Spain with a fellow Tosser in three weeks on it!

So, came across this video... https://youtu.be/-vMS7gRMEz4 - it's exactly what mine does but in fact not as badly as this. It's fine if you can get home without it tipping you off round a roundabout and leave it until next morning - then it's great for another 30/40 miles.

Anyway, anybody know the chap who posted the video... Jonathan Dennis... desperate to pick his brains, or anybody else's who has had and fixed this 'mare?

Many thanks.

Steve

 

[milleplod]

Could be a coil, or coils, failing. If you do a search, there's loads of info on how to diagnose which one(s) it is. AFAIK, a failing one won't throw up a fault code. Easy to swap, not cheap new but there's plenty of used ones about - I carry a main and one of each lowers with me now, after a failure.

Pete

 

[Kersidan]

As milleplod has suggested, I would be looking at the coils initially as these can cause random misfires and don't throw up fault codes detectable by GS 911 diagnostics kit. However I would have thought that BMW and or your tuner would have looked at these as a likely cause. Another thought is plugs, I had a mystery misfire on my GS for over a year, no fault codes, and it would happen under load. I found that one of the secondary plug insulators had a hairline crack. Replaced all the plugs, no misfire and has run like a dream ever since.

What's age and mileage of the bike?

Good luck.

 

[Tractors are go]

Ditto above.

Find out which cylinder is misfiring, disconnect secondary coil from side 1 if it makes it worse, then side 2 is faulty. If no difference it is side 1 that is problem.

Next do primary coils, same again..

Do not rule out both primary and secondary failing, it does happen.

If, your going to hang on to the bike, consider purchasing a gs911.

They appear here secondhand and will allow you to check electrics etc in realtime (on a laptop).

Hope you get it sorted soon.

Sent from my GT-N7105 using Tapatalk

 

[milleplod]

There's a pair of used mains on eBay, 'buy it now' for £50 delivered, which is a good price - a day to go. Item no. 182726720377. For all the hassle they can cause, I'd strongly recommend doing what I do and carrying some replacements, especially if you're off to Spain!

Pete

 

[SteveM]

I had watery / shitty Tesco fuel once that exhibited similar symptoms. Flushed the tank and ran some fuel from another source through her ('11 GSA) and all was OK eventually.
I've subsequently used Tesco fuel many times as it's the nearest filling station to home and had no problems, but I have friends that would never buy supermarket fuel as they think there's crappy additives in them - not sure if this is an urban myth or not

 

[Bendy toy]

I almost always use Teco's posh petrol. Never had a problem.

Sooty plugs and O2 sensor on the affected side will suggest a faulty coil. Swap primary coils left/right and see if the cold header pipe swaps. You might need spare spare plugs if the original is very sooty. Only snag is when both coils are failing this might not help much. They tend to fail in pairs.

If the coils are black painted and smell of hot insulation, they are well past their best and likely to fail any time. Cost new >£80 each.

 

[Steve Robinson]

Many thanks guys... bike is 2013 with 9500 miles - 2000 done by me.

Going down the route of thinking we need a spares package for Spanish trip.... but plugs/coils and injectors and immediately fit to bike. Take it out and hope it's fixed... if not have eliminated obvious.

Assume fixed we have set of spares - one or more components faulty but what the hell - can swap about to identify.

Am I missing any obvious components?


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[Steve Robinson]

Ps... mate Tosser has 911.


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[Bendy toy]

GS-911 won't directly diagnose a coil fault. You have to look for other symptoms.

 

[Steptoe]

GS-911 won't directly diagnose a coil fault. You have to look for other symptoms.

There are a lot of faults that the GS-911 doesn't pick up.

A bad TPS being one of them. A faulty TPS is strange as sometimes it'll show up and other times it doesn't.

So you'll need to use old school diagnostic procedures along with the GS-911. Which seems to be beyond a lot of new "technicians" in the trade.

 

[Norfolk Tiger]

So you'll need to use old school diagnostic procedures along with the GS-911. Which seems to be beyond a lot of new "technicians" in the trade.

And when the computer says a component is faulty it has to be that component to blame................
We see a lot of cars that have been elsewhere and had something replaced which has not cured the issue. The most common is ABS faults where wheel speed sensor is changed but it is the wiring to it damaged so the computer can't see it so assumes it is faulty.
Diagnostic equipment only ever as good as the "technician"

 

[buncobooth]

My friend just had this exact problem, started misfiring every day in the afternoon on a tour of Ireland, then when we got back it was fine. It did turn out to be a bad fuel injector in his case.

 

[Bendy toy]

There are a lot of faults that the GS-911 doesn't pick up.

A bad TPS being one of them. A faulty TPS is strange as sometimes it'll show up and other times it doesn't.

So you'll need to use old school diagnostic procedures along with the GS-911. Which seems to be beyond a lot of new "technicians" in the trade.

I had a VW diesel blow a turbo air hose. I heard it go and the exhaust was as black and sooty as we'd expect. The VW tech was 100% convinced it was caused by a faulty EGR valve. Changing the valve of course did nothing. All because dropping that under tray to actually look at the problem was sooo messy.

 

[Popell]

not sure if the 2013 has same coils as 2005 but I have a bunch of spare ones here in Wetherby if you want to swap about and try.

Certainly sounds like coil problems, developing with time and temp hence ok at start when cold.
Give me a shout if you want to try some, I'm not far from Bingley

 

[Bendy toy]

Later coils have a stainless steel jacket and are considered more reliable than the older black painted type.

 

[Popell]

Later coils have a stainless steel jacket and are considered more reliable than the older black painted type.

That maybe so but are the coils the same basic spec and will they fit?
A working black body is still better than a fubar'd black'un even if the silver bodies last longer.
Still on my original blacks at 12 years old, just bought the spares as they were offered to me

 

[Bendy toy]

My bike fubar'd it's black coils. Stainless jacket coils were a straight swap. But it's an expensive option of the coils are not the problem.

 

[newman7096]

I've just replaced my coils as my 2009 was running poorly below 3000rpm and especially when filtering or riding below 3000rpm. If you warmed it up it got worse and would hunt slightly at idle. Anything above 3000rpm was fine. Found some Beru coils on the web at 'Brooks Barn' £69 a side. Decided to get secondary's as well from M&P. All problems now resolved.

 

[Bendy toy]

My eecondaries are looking well past their best. My plan is to fit some 3 wire stick coils from a car and run HT leads to the plugs. I need to find the correct coil spec of course.