Hoping the experienced tuners on the board can give me some pointers with this one.
Finally had an Arrows full exhaust fitted to my S4Rs, and the ECU tuned for it by my preferred workshop, using Tuneboy (which AFAIK allows complete control). Haven't been happy. Also haven't ridden a DP-chipped S4Rs for comparison.
Bike pops a lot on overrun, is very rough on small throttle openings under 3K, and has lost that smooth Ducati lope on steady throttle in top - all cruising speeds from 60-100mph (and probably above but I don't tend to cruise over 100). Roughish, so right hand goes to sleep.
Runs better when accelerating, and smoother and stronger than stock when accelerating above 7K. But still seems to lag the throttle a bit. I find myself winding on more throttle than I remember having needed stock to get the jump I am looking for.
But ... and here is the interesting bit.
On a longish ride last weekend she came good over one nice stretch of curves, and late in the day came good again over the last 60 miles to home. By came good, I mean she worked better even than I had hoped from the tune. Can't say too much about the low-end stuff, but the steady cruising felt wonderfully loping in the 55-80mph range where I used it over those stretches, the throttling felt wonderfully precise and fluid, and the harshness and roughness had gone. Bliss!
Started her for my commute yesterday morning and the roughness and popping was back.
So ... initially I had thought the tune needed adjustment for steady throttle conditions. But the intermittent perfection has led me to wonder whether the tune was superb but some other issue has arisen coincidentally with the tune being completed.
For example, has a bad connection to some sensor or other key part arisen from the dyno work?
My first guess is that the air pressure sensor has malfunctioned for some reason, leading to general leanness (but that it came back intermittently for the good bits).
Some key background:
- dyno result from the tune was 128hp max at the wheel, with baffles in and stock airbox (Dynojet). Stock was 115 max.
- I am sure the shop will work with me on this, and I sent them a similar query yesterday. Very good guys and I've been with them for six years. But it is a busy time for them and so I am looking for any intelligence I can muster that might help, so that when I do take her in again we can get quickly to the heart of things.
- I have been back once for a tweak, but that was prior to the experience of the bike coming good. The result was a small adjustment, which did help a bit. I am suspecting now that they just didn't consider the possibility that their entire map was compromised by a malfunction. (I certainly didn't, in explaining the problem.) Yes, they did test-ride when I brought her back in. But opportunities to test efficiently and thoroughly from their location are very limited.
- Fuel consumption: over the 100 miles before the last time she came good, 6.4 litres per 100km. Over the 50 miles after she came good, 5.0 litres per 100km (which is about what she returned stock under most cruising conditions). Over the higher consumption period I was also riding faster, averaging say 75mph compared with 60 for the latter period. So that would account for some of the higher rate. But I am sure the lower consumption was also connected with the smoother running. The motor felt soo much better (which is why I refuelled to test usage).
While the higher consumption during the poorer running might suggest that the fuelling was too rich then, my intuition is that in fact the bike when running poorly is lean.
Suggestions sought from those with some insight.
Update: diagnosis reported on page 2, reply 23.
Fresh update: Stepper motor theory. See page 3, reply 35.
New update: Not the coil, after all. Not the ECU either. Problem remains. Next step: the TPS. See page 3, reply 41.
Leaner does not necessarily mean better fuel economy, and richer does not necessarily mean better running.
Do have them check for proper function of all sensors.
New fuel filter wouldn't be a bad thing to try.
How many miles on the bike and when were valves last done?
All of that is baseline upon which to build a good map.
Then, ask them to concentrate on tuning the under 25% throttle zone.
Bike has 33,000 miles, valves were done at the 30,000 major service, along with a new fuel filter.
Thanks for the input, Speeddog. Helpful info on the relation (or not!) between leanness and fuel use.
Hadn't thought about a fuel supply issue, but I daresay that is a possible. Just because the filter is new doesn't mean it's not picked up some rubbish.
The standout thing for me is that the tune has come good now, intermittently, as I noted above. I'm reluctant to fool with the mapping, because when it was good, it was very, very good.
Sounds like there is no obvious intermittent issue that would generate the symptoms though. Damn!
Valves and fuel filter done recently, so baseline is theoretically good.
Quote from: Moronic on December 03, 2013, 04:36:42 PM
~~~SNIP~~~
Sounds like there is no obvious intermittent issue that would generate the symptoms though. Damn!
Quick check with diagnostic software will determine if sensors are giving believable readings.
Perhaps a sensor electrical plug isn't secure, or a terminal is pushing back when the plug is connected.
It would be worth disconnecting, visual check, and reconnecting electrical plugs, watching the wires to see if they push out.
Bike been exposed to water recently?
Thanks again for the conversation, Speeddog. I picked up some conductive grease last night and plan to check some electrical connectors/plugs today, beginning with the air pressure sensor.
Bike is ridden in all weathers. Have had a previous non-start issue that turned out to be a corroded connector shorting the main fuse.
So, a problem with an electrical plug sounds quite likely.
What do you mean with "a terminal pushing back"? Broken plug with a pin failing (or partially failing) to enter its socket?
Quote from: Moronic on December 03, 2013, 05:43:33 PM
~~~SNIP~~
What do you mean with "a terminal pushing back"? Broken plug with a pin failing (or partially failing) to enter its socket?
Yes, either the plastic plug cracks/fails or the locking tab on the pin or socket fails.
It's not common, but it can provide no/intermittent contact in a plug connection that looks perfect.
Usually the pin/socket mate just enough to pull back into position when the plug is disconnected.
So a visual inspection of each plug half shows all pins and sockets look good and in position.
Got it. Thanks very much. Would never have looked for that. [thumbsup]
Problem seems to have been sorted. Not definite what was wrong but a 20km test ride tells me she idles smoother, runs smoother, has much better throttle response and is smoother on overrun. Still a few stumbles around 2k and 2 per cent throttle but nothing like it was.
Bet she has more up top, too.
The air pressure sensor plug looked clean and dry but I added some dielectric grease before closing it up.
Also looked at the big plug behind the steering head that had blown the main fuse a few years ago. Noticed it had not been seated fully home in its socket by the last person to pull it. Added some grease and seated it properly.
Think I pulled and greased three other plugs that were easy to get to. One was the sidestand plug. Another was behind the headlamp, throttle side. Third was on the frame alongside the coolant catch bottle, throttle side.
Replaced the cable tie that had held a knot of wiring behind the headlamp with another that I left a little looser.
Anyway, the result is the one I wanted (assuming it is not something else that has intermittently cured itself right after I checked all those plugs >:( ).
Thanks again Speeddog for the support. Helped me believe I wasn't wasting my time. [beer]
Remove those pesky baffles and the airbox top. You can thank me later.
LA, when running properly she cruises quietly now which I do like. The pipe is an Arrow, so I imagine noisier than Termis with the baffles out. Mufflers certainly seem much shorter.
Maybe one day I will pull them and open the airbox. However, the hp boost my guys got over stock using Tuneboy matched the dyno run shown on bikeboy for the DP full kit, so there is no shortage of go.
They said that if I'd done the airbox and baffles also, they'd have got past the 130hp mark easily. Nice to learn, given it had 30K miles.
On a less satisfactory note ... the poor running is back. [bang] Took her out for a 200km test run Monday night and she lasted a bit more than half distance before the roughness etc returned. >:(
So, not sure where to go now.
Have been in touch with the workshop and they say they are chockas till after Christmas. Said I could replace the pressure sensor but that they have had a bike in where the problem was a broken wire and the sensor was fine.
So it looks like I am stuck with a poor running bike for a month, or could risk the purchase price of a sensor.
At least I can be sure it is not the tune itself causing the problem.
Thoughts very welcome but probably not much you can say. Needs a check from a diagnostic tool, presumably.
I won't be much help with the general problem but the "Still a few stumbles around 2k and 2 per cent throttle" issue will probably never go away. I have the full DP kit on my S4RS and the bike runs very strong except for that one range which is just the nature of the beast I think. Other than that my only problem is keeping the front wheel down under hard acceleration
Thanks for the info. I'll admit I was assuming the DP ECU had that aspect sorted, perhaps by retarding the ignition a bit in that area of the map.
I've replaced the air pressure sensor but the problem persists. Interestingly, it is becoming more intermittent rather than less - that is, the bike runs well more often. To me that suggests an earthing issue rather than a failed part. But what do I know.
I've an appointment with the workshop next week. With some luck, a diagnostic tool will throw up an error somewhere and we can sort it quickly.
Will update then.
Well the upshot, peculiarly, seems to be that the poor running has been connected with my use of the local super-premium petrol. Peculiarly, because I have been running this fuel in the bike almost exclusively on the stock ECU and exhaust for 50,000km with no problems whatsoever.
Nevertheless, when I took the bike in yesterday for diagnosis the system showed no fault history at all. They recalibrated the TPS and the new air pressure sensor I had fitted, just in case it helped, and sent me off to try it with the suggestion that if it didn't help, I fill the tank with the lowest-rating petrol available here.
Well, the tweaks made no difference, but after filling an almost empty tank with the different fuel, the bike came good over the next 3km and has been good since.
I am a bit shocked this bike with 11.5:1 compression will run without pinging on the local base-grade fuel, but it seems to. Suppose it helps that Ducatis won't take much throttle at low rpms in any case.
Early days as I have only run through a single tank.
If anybody has a theory about why fitting an Arrow full-exhaust and remapping the ECU would make the motor extremely sensitive to fuel additives I'd be glad to hear it.
It wasn't just a bad fill of the super-premium that had led to the problem. I'd used probably 20 fills of it drawn from various parts of the state with the new tuning, with consistent poor running.
One possibly relevant tidbit: the first time (prior to yesterday) when I noticed the motor suddenly come really good on a trip, was just after I had refuelled. Only thing is, I am pretty sure I had refuelled with super-premium. It was however at a fairly remote rural fuel station.
The shop i use - Pro Twin in Perth - has not developed a solid explanation for this phenomenon. But said they had noticed it on a range of bikes that had come in running poorly, beginning with a bevel motor. After tearing their hair out looking for the problem, they had suggested the fuel and that had done the trick.
Thoughts welcome.
does anyone know if the Ducati has a knock detector that automatically retards the timing?
Quote from: dbran1949 on January 15, 2014, 05:11:41 PM
does anyone know if the Ducati has a knock detector that automatically retards the timing?
No knock sensors on Ducatis.
Is your local high octane fuel ethanol laced? Back in the old days before E10 using fuel with a higher octane than needed was just throwing away money. Not so today. Ethanol does not atomize as well as gasoline.
Howie, it's not stated on the pump that the 98 RON fuel here has ethanol in it, and so I think it is ethanol-free. Good thought though.
She seemed to go bad again on the freeway today. Something tells me this isn't over yet after all. ???
Okay, if it's NOT the fuel, and there is no error history showing up on the diagnostic tool, what else could it be?
Just to reiterate from earlier posts, bike has 55,000km, new fuel filter was on the service sheet from 7000km ago, when the valves and belts were also done. Went into the shop at around 51,000 running as well as ever on the stock system, came back with an Arrow pipe and remap and this intermittent problem, which for the first 3000km was simply a problem (which I thought was a mapping problem) then came good intermittently.
Today I was riding along the freeway thinking: no this still isn't quite right, the motor feels "tight", like it is too tightly bound to the throttle and there is no overrun nor that feeling of ease a duc has when running well. Felt lean to me. Still felt smooth though, which meant it hadn't gone fully bad. Then my right hand went to sleep, a tell-tale sign, and I realised it probably had (just) gone fully bad. Was heading home and so turned onto a normal metro road soon after.
Water in fuel? Dud spark plug? Gunked up injector? ECU responding badly to the Tuneboy treatment? Dodgy fuel pump?
When she is running well, she sort of squirts off the bottom in the lower gears when you use just a little bit of throttle. When running badly it is as though you have to haul her along with the throttle. (The difference is much more subtle than I've made it sound, though. It is more like the contrast between eagerness and indifference.)
Shop tested the TPS, said it diagnosed fine, but recalibrated it.
How big of a deal is it to re-flash the ECU again?
I'm thinking there's something dodgy there.
The ground wire under the aft bolt attaching the ECU is there, yes?
Quote from: Speeddog on January 16, 2014, 08:52:22 AM
How big of a deal is it to re-flash the ECU again?
I'm thinking there's something dodgy there.
The ground wire under the aft bolt attaching the ECU is there, yes?
Good possibility considering the time line. Might not be a bad idea to empty your fuel tank and in stall a new filter first.
Thanks guys very much for the thoughts, I will have a look at the ECU but I don't think they've needed to move it so it should be the same as it was beforehand.
Re the flash, I think they reflash it every time they adjust the map, and they made a couple of changes the first time I brought it back, thinking just the map was out a bit for steady cruising. So unless there is a real problem with the ECU, I think that is okay.
I am starting to think it must be a fuel filter issue, maybe getting cleared sometimes at least a bit when I fill the tank.
Shop will fit a fuel pressure gauge and also clean out the tank, and we'll see. When they've a slot available. Sigh. This is getting very frustrating. I appreciate the support. Still seems weird it made good power on the dyno, but felt odd when I rode it away from the shop. Yet has come (very) good a couple of times.
Are they running the bike on the dyno simulating throttle opening and load where you are having the problem or mapping at wide open throttle full load?
Not quite sure how they do it, but from discussion it appears they do run it on the dyno under a range of throttle settings, then test-ride for the very low-end and steady cruise stuff.
Point I was making though is that it made 128hp on the dyno with stock airbox and with the baffles/db killers still in the Arrow mufflers. On a dyno that measured it at 115 stock. And even more to the point, on those occasions when it has come good on the road, it has been very good right through the range.
So it seems implausible that they could have tuned it so well if it was exhibiting this issue all along. And then test ridden it and concluded it was all good.
On the other hand, she felt less than stellar to me on the suburban ride home after i picked her up.
So, either something has happened between the tuning and my arriving to get it.
Or, the implausible is nevertheless actual and the bike ran well enough in its rough state to make that number at the top and produce a good looking curve. (Which I'll admit is wavy at the low end, so perhaps a sign all was not right. Sorry, don't have an electronic copy.)
Or something in between, I suppose.
Which still raises the question: it was running fine stock, so what has happened since? (Remembering that it's not the map itself, because it still runs fine sometimes.)
Do ask them what they find when they clean the tank.
Okay, it feels like I have been chasing this problem forever but I suppose it has only been a few months. And I think my shop, Pro Twin in Perth, Western Australia, has got to the bottom of it.
It took me a while to convince them there really was a problem. But once they got onto it, boy did they look into it thoroughly.
The misfiring and stumbling arose at very small, constant throttle openings and revs under 6K. When they put the bike on the dyno to check it in these conditions, the fuelling on the rear cylinder showed up as very spiky and lean.
What was causing that?
Pro Twin checked, adjusted or changed just about every possible problem part. That included ECU, coils, injectors, fuel pump and filter, crank sensor, compression, valve clearances and valve timing, retune with open airbox and no muffler baffles. No joy.
Finally, it was observed that the rear throttle body was sucking in air through the butterfly pivot bearing, which when removed proved quite worn.
A fresher set of throttle bodies was substituted.
Lo and behold, the stumbling and misfiring diminished dramatically. I have put 1200km on the newer throttle bodies, and while you can still feel a stumble when cruising, a lot of the time the bike feels much like it had on those few occasions when, as I noted in previous posts, it felt like it had come good.
Pro Twin has proposed that the problem originates with the Arrow exhaust. They think it is generating a very low pressure zone downstream of the throttle butterfly at small openings, which is drawing air through the bearing and leaning out the mixture. They think the effect is more pronounced on the rear cylinder, which is where most of the misfiring occurs.
Or at least, that's how I understand what they told me.
I think the "coming good" was a matter of the butterfly spindle from time to time settling differently in the worn bearing and closing or partially closing the air leak. At least, that hypothesis seems consistent with the range of performances the bike has exhibited since the exhaust went on.
The bike is now much better, but given the riding conditions over here - lots of boring stuff on the way to the corners - I would love to be done with the stumbling altogether.
So ... does anybody know of an S4R/s Monster with a full Arrow exhaust that doesn't stumble in steady cruising around the 70mph mark?
And secondly, what do people think of the suggestion that the Arrow is short on back pressure and has anyone found a way to compensate for or resolve that?
BTW: the upside of the Arrow is obviously the free flow when you open her up. It is an exciting exhaust when you're on it, and I'd not be at all surprised if it offers a few more ponies up top than its rivals. ;D
Wow.
So your model's TB's don't have a seal on that part? You would reckon there should be a seal on a moving part that could leak air under vacuum. Brad and others would know. I ask because I have seen TB seals available through one of the forum sponsors CCW, but I think they were butterfly shaft/spindle seals. You said butterfly pivot bearing. You would think there should be a seal in there somewhere. I'll go and have a look and come back.
Anyway someone will chime in, or you could contact Brad, Speeddog, etc. Might be worth hearing what Chris at CCW has to say?
I checked and found a seal "throttle shaft Viton U Cup Seal". I don't know if it relates to your TB part. It is in the Californian Cycleworks MAINTENANCE Section under 'Seals and O-Rings'.
What part does your manual identify?
Interesting to see how servicable the throttle bodies are.
Thanks for the suggestions. Yes I meant the spindle, which rotates in a bearing of some kind I assume. So a spindle seal would do the trick, all else being equal.
Problem is though, it is not often that seals outlast their bearings. I saw the original rear throttle body and there was A LOT of play at the spindle. Depending on how the seal works, I imagine you'd need to do the bearing as well. A bit disappointing at "only" 55,000km.
Looking at the parts diagram on Ducati Omaha's site (http://www.ducatiomaha.com/products.asp), it appears the throttle bodies come as a set and Ducati doesn't supply basic components for them. Don't know whether you can get parts elsewhere. Can I assume they are off-the-shelf bits from Magneti Marelli?
The thing is, the motor wasn't stumbling when it was running the stock exhaust, even with the wear on the throttle body. That is why the diagnosis was so long in coming. So I'm guessing the seal isn't designed to be under much pressure. Happy to be corrected on that.
The TPS is also critical for correct low speed running
Thanks jerryz for responding. They have checked and recalibrated the TPS also, and then just in case the diagnostics missed something they substituted another TPS for the original and tried that.
I very much doubt Pro Twin has overlooked a parts failure. They have been over the bike very carefully, putting in big hours - and on their own time, not mine. I've named them here only because I think they deserve public credit for an incredible level of dedication to satisfying the customer. And it is not as though they are short of things to do - they are a very popular workshop and you can wait a month for a booking there.
And to reiterate from my earlier posts, the bike had been running great on the stock exhaust when I brought it in.
However, the implication of all their hard work is that the uneven running does originate with the exhaust.
So, either
(a) there is a big bunch of stumbling, Arrow-equipped Testastretta Monsters out there getting steadily worse as they wear, or
(b) someone, somewhere has found a way to tune out the stumble.
If it's (b), I'm sure the shop will be almost as happy to hear about it as I will be. No-one knows so much that they can't learn something new.
Relatedly, a search on the net has shown up a few threads in which Arrow-ed S4R/s owners complain of a cruising-speed stumble and/or poor low-speed running. In most cases no resolution is reported, while in one case it was reported that the stumble had been fixed by a workshop but the bike's owner had no idea what they'd done.
I should probably get along to the local Ducati club and ask around. A lot of knowledge there. Coincidentally, I was stopped for lunch at a country town last weekend when a group of half a dozen Ducs went through in the 50km/h zone, including a Monster like mine with the same Arrow pipe. it was misfiring audibly just like mine would in those conditions. None of the others was. >:(
Late to this thread, but will toss in my 2 cents:
I had similarly rough low end on my S4RS. Thought it was the nature of the beast, then was about to spring for the ECU re-flash to tame it. Turned out that my fuel sending unit had a tiny, slow leak. It was small enough that there was never any seepage on the ground, but the wire housing was damp. Long story short, ECS replace the fuel sending unit and it now runs very well.
I have an 07 S4RS at 10.5K miles with a full Arrow system, stock air box, and no re-flash that I know of. I run with the DB killers installed. Running without the DB killers causes a lot of popping and was more noise than I cared for. The popping is nearly completely removed by leaving the DB killers in.
I don't have any cruising issues at 70MPH or up to 100MPH that is mentioned. I do have a low speed issue (more like a slight surging) in 2nd gear just under 4K RPM. I figure this is a TPS issue and I have to get my TPS re-calibrated since it's easily reproduced and occurs at a consistent RPM.
Have you tried going back to a stock exhaust to rule out everything BUT the Arrow exhaust? You did say that the bike was running great with the stock exhaust before, but then the diagnosis goes onto other parts of the bike other than the exhaust. Maybe you can go back to the beginning and rule things out by reverse elimination. Not ideal I'm sure but just an idea.
Thanks guys for the inputs.
CDawg, I'm not sure what you mean by the fuel sending unit? Do you mean the fuel pump? The injectors? The hoses connecting pump to injectors?
Ak1nza, it's very interesting that you are happy with the way your full Arrows bike cruises. Have you ridden it with the stock system in place, or did you purchase it with the Arrows already installed?
Yes, the shop has suggested I consider having them refit the stock exhaust and map to test their diagnosis. A lot of work but in the end I might go that way.
Meantime, I will shortly email an inquiry to Arrow in Italy. Perhaps they can shed some light on the problem.
Quote from: Moronic on April 19, 2014, 04:22:47 AM
CDawg, I'm not sure what you mean by the fuel sending unit? Do you mean the fuel pump? The injectors? The hoses connecting pump to injectors?
That's what the shop called it. It's the housing including the fuel pump, filter etc...
Thanks CDawg for the clarification. I'll keep that one in mind, although I'd hope the shop would have found something like that, if it were present, when they tried it with a substitute fuel pump and filter.
Quote from: Moronic on April 19, 2014, 04:22:47 AM
Ak1nza, it's very interesting that you are happy with the way your full Arrows bike cruises. Have you ridden it with the stock system in place, or did you purchase it with the Arrows already installed?
They were installed when I got the bike but did not have the DB Killers installed. Definitely a lot of popping on deceleration without them in, and I much prefer the noise levels with them in than without. Hope you get to the bottom of this!
Thanks Akinza. No response yet from Arrow and it's been a week now. I may have found a similarly equipped bike to compare mine with, which will be interesting. I will keep you all informed.
A couple of other developments.
I've noticed that the "coming good" I reported earlier is still there with the fresher throttle bodies. It is just that the bad isn't nearly as bad, and the switch from good to bad is, if anything, better defined.
A tell-tale is the crispness off the bottom when, say, changing down for a slow corner, or engaging the clutch to pull away from a traffic light. When it's bad, it's quite obvious the bike is relying on one cylinder when responding to those first few degrees of throttle rotation. I need to exaggerate my throttle movement to bring in the rear cylinder and get the engine to spin up properly. In contrast, when the bike is good she is quite crisp off the bottom, with the usual small squeeze on the throttle doing the trick as expected.
The second thing is that I've bought a spare set of throttle bodies off eBay from a bike only 6000 miles old. (Great service and value from rubbersideup.com (http://www.rubbersideup.com/servlet/the-Ducati-cln-Monster/Categories) BTW.) Given the wear in mine at 35,000 miles I thought a spare might be handy, but I also wanted to look at whether that leaky spindle could be sealed in some way.
However, the cover-it-with-your-mouth-and-blow test tells me that on this unit anyway, there is no way air can get past the existing seal on the non-actuator side of the rear throttle body. The actuator side I can't test, and it makes sense that this is where most of the wear occurs. It looks like there is a seal of some sort on the spindle housing that could certainly wear. And there is no other way I could seal that.
However, it is hard to see how wear in that part could produce the sharp transitions between running smoothly and running poorly that the bike exhibits. Of course, it is possible that it could. ???
Okay I've just had the bike away solo for a 1000km long-weekend and those transitions between great and okay were fairly frequent and obvious.
(http://www.smugmug.com/photos/i-fTTZ6wz/1/M/i-fTTZ6wz-M.jpg)
Great also lasted a hundred km or more on various parts of the trip. Way too long for it to be attributable to that throttle housing leak having closed up, IMO. A leak of that kind should be fairly steady, you would think.
As well, when it was great the bike was running so damned well that it's very difficult to attribute problems to the Arrow exhaust. It's bloody wonderful. Produces a range of notes from the bottom to the top of the rev range and it is difficult to want any other exhaust. And the motor feels so smooth. (Thanks, Pro Twin.)
When it's just okay? We are back to the cruising speed stumble, but the not-so-good-ness is most obvious down low, where as noted in earlier posts the bike runs quite roughly. What is also obvious then is a change in the exhaust note: when the motor feels good, the exhaust note down low is richer and more rounded; when it's bad, the note is sharp and blaring. Leanness for sure.
What else? Well, the transition from okay to great often occurs after I've stopped the bike. As in, switched the ignition off and then on again. Given that on an S4Rs that mainly happens at fuel stops, it is easy to see how I was happy to connect the "good" with refuelling.
So what has occurred to me with a great deal of insistence is that the issues I have been having are very likely connected with the stepper-motor fast-idle system. Either it's developed a fault all by itself, or it's not working properly with this exhaust.
The valve is supposed to cycle automatically whenever you switch the ignition on. The possible volume of an air bleed through the valve would likely dwarf that through the spindle housing. Transitions could be sharp-ish if the valve was opening and closing. It would be impossible to tune out the effects of the air bleed by adjusting the fuelling, because the volume of air would be relatively large and changeable. And the valve now on the bike is the valve that came with the substitute throttle bodies, which alone could have produced an improvement in the way the motor behaved.
Pro-Twin tried running the bike after closing the valve and unplugging it from the electrical system, and also attempted to clamp closed the connected hoses, with no improvement. I assume this was on the dyno. They said they did not disconnect the system and plug the ports, and try riding the bike like that.
So that is the next step I'll be trying, and I have a feeling this one will do the trick. Can't see what else it could be.
Comments welcome.
Okay, some fresh info on this. And still no solution.
1. Disconnected the stepper motor and fast-idle hoses, plugged the spigots. No improvement. Damn. [bang]
2. Spent a day on the road with an acquaintance who has an identical model S4Rs to which he had fitted an identical Arrow exhaust. His bike was purchased used, on stock exhaust but with no O2 probe fitted (I am guessing a reflashed or DP ECU, owner doesn't know). The Arrow was simply bolted on, with no retuning. I rode his bike. Findings:
a) His bike was beautifully crisp off the bottom and stayed that way.
b) It showed none of the switching between good and not-so good that mine shows. (None reported either.)
c) It misfired a bit in the 3.5-5K rpm range. Never felt as laboured there as mine can, though.
d) It used much less fuel (about 20 per cent less, identical use, range of speeds).
All this supports my thought that it's not the pipe, and it's not just the throttle spindle. But if it's not the fast-idle system either, then what?
Leak at the vacuum gauge port? Cracked rear manifold? Anyone ever seen these?
Quote from: Moronic on June 12, 2014, 02:39:48 AM
2. Spent a day on the road with an acquaintance who has an identical model S4Rs to which he had fitted an identical Arrow exhaust. His bike was purchased used, on stock exhaust but with no O2 probe fitted (I am guessing a reflashed or DP ECU, owner doesn't know). The Arrow was simply bolted on, with no retuning. I rode his bike. Findings:
Are you saying your bike does still have the O2 sensor connected? I *think* that could be a problem if so. My bike never ran right with the O2 sensor connected, ran better with it disconnected (default map I think). When the DP ecu was installed, I was told that if the O2 senor was present the DP ecu would use it. With the stock ecu (non-flashed) you will get a check engine light when the O2 sensor is disconnected. Worth a try for testing purposes anyway.
Hi Bill, no, my bike has been dyno tuned and reflashed specifically for this exhaust (using Tuneboy software).
That included removing the O2 sensor and switching off that part of the ECU that would look for it.
Good thought though. Thanks for your input. [thumbsup]
Quick update to say that I have finally sorted this problem - I think about a year after I got the work done.
It was the f*%@ing rear cylinder coil.
Yeah I know that was supposed to have been checked. But there's many a slip, etc ...
Since my previous post on this I had fitted a parallel earth cable to a new earth point using the Motoelectrics kit, and also cleaned up the stock earth point. That helped, but the switching between sweet and laboured running remained.
On an overnight run to test this, there was a period soon after start-up when she dropped a cylinder. After a minute or so of running on one she came back onto two. And had run on two ever since.
But as I had run out of new options, it appeared the next step was to try stuff that had already been done. And as one obvious source of a drop onto one cylinder was the coil (plugs being quite new), I decided that was the next step.
The front coil was also new. So I replaced the rear, thinking to myself that I had just thrown another $250 into the wind.
Well whaddaya know. She started better, idled more smoothly, produced a quieter, richer note, ran nicely around town, and on a 350 mile country run completed a couple of days ago ran smoothly and eagerly at cruising speed - pretty much like she had at the best of the "good" times.
Yes I am pissed off that such a simple problem led to this much heartache, grief and expense - and not even just for me.
Yes, that is very much overidden by delight in the bike now running properly.
I'm not sure whether the coil failed on the dyno, or whether it had been on the way out but still doing the job with the stock exhaust. It could be that small-throttle combustion conditions are significantly more challenging with the 50mm Arrow headers than with the stock pipe.
I think she is now running a bit rich, so will look into that.
Thanks to all those who offered help and support. ;D
A completely failed coil is easy to diagnose. A weak or intermittently failing coil not so easy. There are two ways to pinpoint a weak or intermittent failure. One is what you did. Replace it. The other requires an oscilliscope, something rarely seen in a motorcycle shop, not sure why or a coil tester, which seem to have disapeared from the industry decades ago. Oh, a third. If the failure happens often and long enough, swap coils from cylinder to cylinder. Glad you got it fixed [thumbsup]
Unfortunately I need to extend this thread and reveal that after more riding the intermittent poor running has returned. It appears the fitting of the fresh coil merely coincided with a period when the bike was intermittently good. [bang]
Since then I have fitted a fresh ECU (thanks Brad Black) and determined that the ECU is not at the root of this either.
I also tried disconnecting the coolant temp sensor that supplies the ECU, to see whether it was intermittently failing to tell the ECU that the bike had warmed up. I did this at a time when the bike was hot and running poorly. If it hadn't run any worse, then that sensor would look like the culprit. It ran much worse. So, not the coolant sensor.
What is left? The air pressure/temp sensor I replaced early in the piece. Pro Twin regapped and then replaced the crank position sensor, to no avail.
An injector might be faulty, but it's a funny sort of faulty injector that displays the same low and mid-speed fault for 10,000km and still allows the bike to rev out and make quite good power at the top.
Short in the wiring loom? Possible. I am hoping not.
Next thing I am going to try is the throttle position sensor. An intermittent fault there seems to match the symptoms I am experiencing, as far as I can tell from reading around on the net. There was a TPS glitch when the new ECU went in: initially a fault wouldn't clear, and then after a few tries and a swap back and forth with the old ECU it did clear. I suspect also that the TPS voltage signal can drift without triggering a fault report on the ECU: it would just think the throttle was moving.
So a fresh TPS is going in around the end of next week. Here's hoping ... >:(
TPS sensor sounds like a good candidate, can you take the connector off and see if the pins look shiny and clean?. I have an S4Rs with Arrows and it runs pretty good. I recently re-balanced the throttle bodies, they were out a lot. It improved my idle and got rid of some popping on deceleration I was having. The balance was good ?3? years ago the last time I checked them. I also found that there is a tiny screen filter in the top of each injector. There was not much there but some fuzz but I guess it didn't hurt to clean them.
Is your tps the linear or non linear? I know the manually adjustable one can be checked with a multimeter, not sure about the other one.
They can all be checked with a multimeter. Remove the electrical connector from the TPS. Middle terminal in is power in, 5 volts. Since the bike runs, you have that. Figure out a way to back probe the two outside terminals at the connector Attach a voltmeter to the outside terminals. With the key on, move from closed throttle to open throttle at a very slow, steady pace. Your voltmeter should read about 1 volt at closed throttle and smoothly increase to about 4 volts at open throttle. Problem is your symptoms are intermittent, so you might test good when the bike is running well.
Quote from: howie on November 08, 2014, 01:02:41 PM
They can all be checked with a multimeter.......
Some voltmeters are better than others for checking TPS. I've had better luck using an analog rather than a digital one.
Moronic, I didn't see mention of a PowerCommander or such, but by chance do you have one installed? Reason I ask is because I know of one with a PCIII which had an internal fault with the TPS connection. Symptoms were much as you described. It was allowing voltage from the PC to go to the TPS. A diode in the PC to TPS wire proved the diagnosis.
Yes, an analogue meter, even better, a scope is better than a digital meter on this type of TPS since the digital will not be smooth. They are getting rare though.
Quote from: howie on November 08, 2014, 02:48:57 PM
Yes, an analogue meter, even better, a scope is better than a digital meter on this type of TPS since the digital will not be smooth. They are getting rare though.
Low tech is not rare for old timers. ;)
Thanks guys for the replies. No, no powercommander. Tune was done directly with Tuneboy, although at pres i am running the alternative ECU I installed as a check, which has the standard DP Termi map and seems quite good when all is well.
But the fact the PC/TPS connection fault gave similar symptoms to mine gives me hope. :)
Howie thanks for the VM details. Luckily there seems to be an aftermarket TPS available so I have gone for that. Even if mine had tested okay with a VM, I would still have been suspicious.
New TPS should go in Friday but I will give it some test miles before reporting here.
Well the new TPS did the trick ... sort of. ;D
It has cured the poor throttle response and vibration issues. All is much better and I no longer feel like the bike has some mystery gremlin.
I have a pretty good theory about how this got overlooked also. But I will save that.
However she still is not completely happy. [bang] My target at present is the horizontal injector. Since the bike has now done 74,000km - adding up to nearly 20,000 since the tune when it all went wrong - it could easily have gone downhill since the problems began and I wouldn't have noticed.
I will wait until I am fully satisfied and then do a full write up of what has been a maddening but educational experience.
I certainly know a lot more about how the bike works than i did when this started. And I understand better that, umm, joke about Ducati turning riders into mechanics. [roll]
While I am on mechanics, I want to give a big thank-you to Anthony Warnock at Corse Motorcycles in Perth, Western Australia. His patience, availability to make changes one at a time and - most of all - clear communication has allowed me to get - almost - to the bottom of this.
A big number of other people have been helpful also, including the many commenters on this thread. I will offer more acknowledgment after the final piece has fallen into place. Which unfortunately could take another couple of months.
Has there been any progress on this?