Surge City, tried everything?

[ianboydsnr]

It has the 'official' NGK twin-electrode plugs fitted. I've replaced them with new ones but I haven't tried changing the gap - I thought you weren't supposed to do that?

Are those the plugs you mean?

I think mine are bosch, mine surged like hell, untill I bent both electrodes out a bit, try it with the old plugs first

 

[Scuba-Sparky]

Hi All
Sorry dont have any help for you, but my 1150 on an 02 plate has almost the same problems as yours, the only things I have not changed so far are the leads and the hall sensor. Ordering a set off leads when I get paid next.

Scuba

 

[sproggy]

I went out to fill up with petrol just now. I get to the local petrol station before the bike's properly warmed up (2 bars showing, generally, and the bad running starts at 3 or 4 bars) so it's always running fine at that stage. Filled up with the usual and then carried on riding - it was still playing silly bu**ers but didn't seem as bad as before. Then I disconnected the lambda sensor and it improved. Not hugely, but a fair bit - to a level where I could put up with it if a bit of tweaking of the TPS improved it further. But boy, did it backfire on the over-run!

Of course this doesn't prove that the lambda sensor is at fault, necessarily - just that the fuelling without it connected makes the bike run better than with it connected. I'm not sure whether I want to cough up for a new lambda sensor just to try - I've already done that with the coil, leads etc.

I can't help wondering at the improvement that happened (and I think has happened before) when I go from an empty tank to a full one........

Scuba-Sparky, you can check the resistance of your leads - see my post above for the resistance of the new leads I bought compared to the old ones. If yours have a similar resistance then you can probably save yourself the money.

PS I discovered today that the bars/top yolk rock from side to side so there's more to deal with. For a 27k mile, main-dealer-serviced bike it seems to have had a hard life...

 

[ianran]

I went out to fill up with petrol just now. I get to the local petrol station before the bike's properly warmed up (2 bars showing, generally, and the bad running starts at 3 or 4 bars) so it's always running fine at that stage. Filled up with the usual and then carried on riding - it was still playing silly bu**ers but didn't seem as bad as before. Then I disconnected the lambda sensor and it improved. Not hugely, but a fair bit - to a level where I could put up with it if a bit of tweaking of the TPS improved it further. But boy, did it backfire on the over-run!

Of course this doesn't prove that the lambda sensor is at fault, necessarily - just that the fuelling without it connected makes the bike run better than with it connected. I'm not sure whether I want to cough up for a new lambda sensor just to try - I've already done that with the coil, leads etc.

I can't help wondering at the improvement that happened (and I think has happened before) when I go from an empty tank to a full one........

Scuba-Sparky, you can check the resistance of your leads - see my post above for the resistance of the new leads I bought compared to the old ones. If yours have a similar resistance then you can probably save yourself the money.

PS I discovered today that the bars/top yolk rock from side to side so there's more to deal with. For a 27k mile, main-dealer-serviced bike it seems to have had a hard life...

Bloke at Scrimingers told me that the lamba is the bit that deals with constant throttle openings so this may be why you get surging if lamba is faulty.

Ive got a twin spark thats running fluffy on acceleration Ive changed most things and am awaiting a visit to Scrimingers to fully set up the bike.

 

[sproggy]

Bloke at Scrimingers told me that the lamba is the bit that deals with constant throttle openings so this may be why you get surging if lamba is faulty.

I believe it will run in closed loop mode (relying on the lambda sensor to determine the fuelling) at low revs and at small throttle openings - not specifically constant throttle openings (because a constant wide throttle opening would probably have the system running in open loop, taking the fuelling info from a map) but certainly a constant 40mph in 4th (where mine is worst) would be likely to constitute a small throttle opening.

And of course when the engine's cold the lambda circuit is bypassed so, at risk of finding a problem to suit a solution, that might also support a dodgy lambda sensor as being the culprit.

Bosch lambda sensor (single spark) £73.50 plus postage from Motorworks or NGK one from eBay (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=400063239458) for £62 with free delivery. Hmmmmm......

I realise, of course, that spending on a new sensor is no sure-fire way to a well-running bike, but it's probably worth a try. He says, trying to persuade himself....

 

[D6]

disconnect it, mines been like that 2 years
you prob wont believe me , ask steptoe if he,s seen any running without lambdas,

 

[sproggy]

Any noticeable difference either way in fuel consumption having the lambda disconnected?

It is tempting.

 

[D6]

Any noticeable difference either way in fuel consumption having the lambda disconnected?

It is tempting.

non, just try it to see if it stops surging, at least you will know, i THINK it switches to a map that gives it a bit more fuel,i could be wrong,
a little more fuel is no bad thing on a 1150

 

[sproggy]

I have tried it - that's what I tried this afternoon. It's better, but not perfect. I'll try with it disconnected and the TPS adjusted a bit.

 

[D6]

I have tried it - that's what I tried this afternoon. It's better, but not perfect. I'll try with it disconnected and the TPS adjusted a bit.

didnt see that bit
mine was ok without, i have got a techlusion on now, but that was cos i was concerned about poor petrol in eastern europe (unfounded)

 

[sproggy]

Well I think this problem is solved. This morning before leaving for work I reset the Motronic on the theory that perhaps the ECU needs this before it will realise that it doesn't have a lambda sensor connected.

Apparently it does - the bike ran better than it ever has done since I bought it

Quiet at idle (no tapping/ticking/knocking/rattling), no surging or misfiring, revs cleanly throughout the rev range with no hesitation (when hot as well as cold), smooth at all revs and all in all a pleasure to ride. At last. I'm ordering a new lambda sensor today because I'd rather run with one than without, but I am finally happy with the way the bike's going.

Thanks to everyone for their suggestions.

Now I just have to replace the top steering bearing before the handlebars flap so much they hit me in the face.....

There's always something, isn't there?!

 

[bart2181]

sproggy pleased to see you,ve got a resulthow are your spark plugs looking,you,ll have to let us know how your mpg goes without the lambda connected.

 

[sproggy]

I haven't checked the plugs yet. I've ordered a new lambda sensor but I'll check the plugs before I fit it just out of curiosity. It'll run through a full tank before then so I'll also be able to judge consumption - I'll post back here later in the week.

 

[sproggy]

OK, update on how the bike's been running without the Lambda sensor connected. In a word - rich

You can kind of 'feel' that it's running rich, not to mention the LH rear indicator having turned black and the deafening backfires on the over-run that have people running for cover (almost) but the definitive evidence is the fuel consumption which has increased from about 48mpg to 41. OK, it was running like cr*p before and may have been a bit lean (although the plugs were a good colour) but that's a 15% increase in fuel consumption. At this rate the new lambda sensor will pay for itself (when it turns up ) in a few weeks.

In real terms this has resulted in the fuel light coming on at 180 miles instead of something over 220 so it's a whole day less commuting per tank. Good for neither the planet nor my wallet.

 

[monkeyboy]

I've got the same problem - late 2002 and it's doing the slight misfire thing at low speeds, and at 30-50 on a constant throttle it feels like you're making microscopic on/off throttle changes and it can't decide whether to fuel or not. It's fine when accelerating and at speed as your's is. Until recently the tickover was frequently high, the engine was surging and engine braking had all but dissapeared. I swapped the injectors the other night off an old R1100S I have in the garage with 150k on it - so they're worn - but the thing I noticed was that the rear injector O-ring on one side on my GS must have been sitting behind the injector rather than in the grove because immediately I released it it popped out and spurted petrol rather than needed a good tug as they usually do. I made sure the o-rings were seated properly fitting the replacements and for the last couple of days (180 miles) the surging has gone at least. I've still got the micro shunting at 30-50 and the 'missing a beat' thing too. I actually stalled it yesterday for the first time in years cos it dropped a beat as I released the clutch. Might be something to look at - just whip the injectors out and check the o-rings are good and seated correctly. It's fair pissing me off though

 

[bart2181]

i have the same prob too and its also pissing me off,although i,ve taken the ccp out today and its cured the micro miss firing thing but the bike now feels like its over fueling and is reluctant to start from cold.i,ve come to the conclusion many of these gs,s don,t like been fooooked about with tuning wise so i,ts standard exhaust time for me and then i,ll see how it goes.i,m off to grab a beer now see you all later

 

[sproggy]

Just to bring this to a close, I fitted a new lambda sensor last night and the bike's running pretty well - much 'crisper' in its throttle response as you'd expect now it's not having bucket loads of extra fuel chucked into it (which it was without a sensor). Although there's a bit of a flat spot/surge between 2k and 3k rpm this is nowhere near as bad as it was before and I could probably live with it, but I reckon I can reduce it by tweaking the TPS.

Got there in the end.

 

[Hong Kong Nick]

I've got the same problem - late 2002 and it's doing the slight misfire thing at low speeds, and at 30-50 on a constant throttle it feels like you're making microscopic on/off throttle changes and it can't decide whether to fuel or not. It's fine when accelerating and at speed as your's is. Until recently the tickover was frequently high, the engine was surging and engine braking had all but dissapeared. I swapped the injectors the other night off an old R1100S I have in the garage with 150k on it - so they're worn - but the thing I noticed was that the rear injector O-ring on one side on my GS must have been sitting behind the injector rather than in the grove because immediately I released it it popped out and spurted petrol rather than needed a good tug as they usually do. I made sure the o-rings were seated properly fitting the replacements and for the last couple of days (180 miles) the surging has gone at least. I've still got the micro shunting at 30-50 and the 'missing a beat' thing too. I actually stalled it yesterday for the first time in years cos it dropped a beat as I released the clutch. Might be something to look at - just whip the injectors out and check the o-rings are good and seated correctly. It's fair pissing me off though

How long has the bike been doing this? I only ask because I had about 2 weeks of similar before the fuel pump gave up ... when I was riding ... with a truck behind me ... doh! The slight misfirings at low RPM ... sometime behaving like it was going to stall ...

Just a thought ... ?

Cheers.

Nick

 

[Styve100]

sproggy, how do you reset the motronic?

 

[Stewart H]

sproggy, how do you reset the motronic?

Pull out fuse 5 for a few minutes.
Stewart