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General Category => General Discussion => Topic started by: vitsiozo on June 28, 2022, 12:58:24 PM
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Hi, I got a V7 Special 2013 model. I have had an issue a couple of years ago where when starting the bike, it would rev on its own and then not be able to idle properly. This was an intermittent issue (only really happened a couple of times) but on the occasions that it happened it made it very difficult to drive the bike around.
Subsequently I checked the fuelling map that was used on the bike and saw that it was the original version that came with the bike and no update had been made since. I kinda suspected that the fuelling of the bike could be the issue so I took the dive and installed a custom Beetlemap that would also accommodate the after market exhausts I had on the bike. I thought I was done with the problem as for over a year the bike ran without a hiccup.
Just today however the issue re-emerged! I took the bike out for a ride, all was smooth, parked somewhere for a coffee, then came out, started her up and this happened:
https://youtube.com/shorts/q1borOqMAiY?feature=share
Upon starting the bike it revs hard for a while and then cannot settle at idle speed but goes up and down, up and down. Very difficult to control the throttle and the bike switches off easily. The bike was dry as the weather is nice at the moment.
Has anyone seen this behaviour and have any inkling as what might be behind this?
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Throttle cables properly routed and not pinched?
Perhaps a gas tank pressure issue--Have you tried 'burping' the gas tank--open the cap, see if the tank has any vacuum due to changes in atmospheric pressure?
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13-14's had an issue with the spark plug caps, our 14 did the smae thing. Changed them out not an issue since. I am sure there is a thread on here about it, as somone gave me the number back then of the cap I needed. Maybe someone more educated than I will jump in here. I think this was an official recall at the time, check with your dealer.
Try this thread.....
https://wildguzzi.com/forum/index.php?topic=96129.0 (https://wildguzzi.com/forum/index.php?topic=96129.0)
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Start the bike at night and look for the sparks. When was the last time you checked the plugs for an indication of the fueling? Italian tune-up needed. Your riding is mostly in town? What rpm's do you shift at?
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Does your bike have a stepper motor that controls the idle ?
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Hi, thanks for taking the time to reply to me.
Just to answer a few of the points, don't think it's a problem with the throttle cables, properly routed and not pinched. I can check the gas tank to see if this makes any difference even though the idling ups and downs are very periodic, so I can't imagine how pressure could do this.
I am definitely going to check the threads for the spark plug caps and also check the spark plugs themselves tomorrow for any indications.
I don't quite understand what you mean Tom by saying to check for sparks at night.. what am I looking at? Also what is an Italian tune-up? Yes, riding is mostly in town but I take her occasionally out of town for a good stretch where I take her much higher in revs.
Huzo, no the bike does not have a step motor as far as I know.
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‘13-‘14’s had a cold start issue. Somewhat corrected by an updated factory map, but not 100%. Gotta let it warm up for a few minutes before taking off. Wasn’t a big deal for me cause I’m used to old carbed bikes.
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By checking the sparks at night he means that in the dark you should easily be able to see any showing up which means the cap insulation is failing an they are shorting out.
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Huzo, no the bike does not have a step motor as far as I know.
It must, at it needs some method of controlling idle air. I presume it is another unserviceable component of the combination ECU/throttle body.
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It must, at it needs some method of controlling idle air. I presume it is another unserviceable component of the combination ECU/throttle body.
V11's and many Guzzis run just fine with IFE and no stepper motor as do many many Ducati's with EFI. They use air bypass screws and throttle plate stops working in concert for idle control together with fuel and ignition mapping of course. Not sure what the OPs bike uses but if it does use a stepper motor that would be a good place to start looking. Electrical connection first I'd suggest.
Phil
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Vitsioso, an Italian tune-up means to flog the bike for all it is worth in order to blow the carbon off the pistons, plugs & valves. Also, most satisfying and can be performed with any vehicle.
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If it was a car it would be the ecu searching for the signal from the Ox sensor on the exhaust. Usually the sensor is gone and the ecu is searching to add then take out on the fuel. Ox sensors get dirty or wear out.
1st & 2nd gear in town. Maybe once in awhile 3rd gear but only on longer straights. Otherwise too low on the rpm's in town. Check your spark plugs.
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You obviously have the cable with ability to load a map via guzzi diag or other software. plug the bike in and check for fault codes, My guess is you have a bad sensor , as Tom mentioned, sounds like a bad signal from an o2 sensor or possibly the temp sensor. Either should show a code in diagnostics. Another thing to check is your air filter to make sure it is not oil saturated .
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V11's and many Guzzis run just fine with IFE and no stepper motor as do many many Ducati's with EFI. They use air bypass screws and throttle plate stops working in concert for idle control together with fuel and ignition mapping of course. Not sure what the OPs bike uses but if it does use a stepper motor that would be a good place to start looking. Electrical connection first I'd suggest.
Phil
Can't speak the V11 sports, obviously the Cali V11's and the 2 TB smallblocks both used physical fast idle levers.
The CARCs all used steppers.
I've been told the 1TB smallblocks use a bypass valve or something integrated into the throttle body.
But no matter what the solution the ECU can't automatically adjust idle speed unless it has some method of controlling air right?
Bypass screws or whatnot are fine if they are adjusted and set for certain conditions, but what happens on other conditions? And there are no physical adjustments on the 1TB units.
Oh screw this... See link, download PDF, SEE PAGE 7, Stepper Motor:
https://www.guzzitek.org/documents/injection/ECU_MIU-G3_Training.pdf
Ha ha sorry got tired going from memory...
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Check fuses?
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Can't speak the V11 sports, obviously the Cali V11's and the 2 TB smallblocks both used physical fast idle levers.
The CARCs all used steppers.
I've been told the 1TB smallblocks use a bypass valve or something integrated into the throttle body.
But no matter what the solution the ECU can't automatically adjust idle speed unless it has some method of controlling air right?
Bypass screws or whatnot are fine if they are adjusted and set for certain conditions, but what happens on other conditions? And there are no physical adjustments on the 1TB units.
Oh screw this... See link, download PDF, SEE PAGE 7, Stepper Motor:
https://www.guzzitek.org/documents/injection/ECU_MIU-G3_Training.pdf
Ha ha sorry got tired going from memory...
Yep and so does the V11 Sport and the Daytona and Centauro. The point I was making is many older EFI engines control the idle without a stepper motor so it's not a mandatory thing to have. When the engine is cold you can use the fast idle lever or the throttle to maintain an elevated rpm for warm up. My V10 Sport starts and idles without the fast idle lever or throttle at any temps from 10 deg C to 40 deg C. Then again it's been mapped by me not the factory.
Ciao
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Yep and so does the V11 Sport and the Daytona and Centauro. The point I was making is many older EFI engines control the idle without a stepper motor so it's not a mandatory thing to have. When the engine is cold you can use the fast idle lever or the throttle to maintain an elevated rpm for warm up. My V10 Sport starts and idles without the fast idle lever or throttle at any temps from 10 deg C to 40 deg C. Then again it's been mapped by me not the factory.
Ciao
:thumb:
Ahhh, ok I see where you're going. But it's not in conflict with my logic. An ECU cannot control cold and hot idle speed without something like a stepper/bypass. Now maybe there's an exception somewhere that uses say ignition timing or something to affect idle speed.
But absent an automatic/ECU controlled system there's a mechanical method that's adjustable. I knew the 1TB didn't have that and seemed to "control" idle speeds therefore there has to be a mechanism.
Your lack of need got the fast idle lever for cold streets suggests richer mapping and probably idle speeds that vary somewhat from spec (neither of which are necessarily problematic). EFI does have an advantage over carburetors here in that it can enrichen mixture for cold starts without needing to mechanically limit air for the same result or open an additional fuel passage etc. But it still doesn't actively control the speed without additional input if that makes sense.
Anyway op, let us know what you find.
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:thumb:
Ahhh, ok I see where you're going. But it's not in conflict with my logic. An ECU cannot control cold and hot idle speed without something like a stepper/bypass. Now maybe there's an exception somewhere that uses say ignition timing or something to affect idle speed.
But absent an automatic/ECU controlled system there's a mechanical method that's adjustable. I knew the 1TB didn't have that and seemed to "control" idle speeds therefore there has to be a mechanism.
Your lack of need got the fast idle lever for cold streets suggests richer mapping and probably idle speeds that vary somewhat from spec (neither of which are necessarily problematic). EFI does have an advantage over carburetors here in that it can enrichen mixture for cold starts without needing to mechanically limit air for the same result or open an additional fuel passage etc. But it still doesn't actively control the speed without additional input if that makes sense.
Anyway op, let us know what you find.
True.
The 15M,15RC,16M ecu has cold enrichment that trims the fuel injector duration with regards to inlet temp and engine temp. So obviously in low OAT and engine temps you get more fuel. On top of that there is cranking enrichment which also adds even more fuel for the first 4000 engines revolutions after starting which tapers off to zero trim after 4000 revolutions have occurred. Paradoxically this enrichment trim happens every time the engine is started irrespective of the engine temp. My engine will idle when cold without throttle input, a little low and erratic until it gets some heat into the heads which helps the fuel vaporise but it doesn't stall.
Phil
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Hi and thanks for all your replies. I am sorry I cannot contribute to the stepper motor question as my knowledge is very limited on this, I just did not find any mention of such thing in the manual and assumed the bike does not come with one.
Coming back to the issue however, I think that @vintagehoarder must have had the point. I removed spark plug caps and spark plugs this morning for inspection. I am attaching the images of each. There is a significant difference in how they look. It's the left hand side cylinder which looks much more black/oxidised. More interestingly however is the fact that upon reassembly and starting up the bike again the spluttering, inconsistent idling and cut-offs have now gone.
So I am probably looking at an intermittent problem caused by the spark plug cables ...
(https://i.ibb.co/2ck80sn/IMG-9584.jpg) (https://ibb.co/2ck80sn)
(https://i.ibb.co/FgnqNSM/IMG-9582.jpg) (https://ibb.co/FgnqNSM)
I will try to search this forum for information about problems with this year models and see what I can find.
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Hi and thanks for all your replies. I am sorry I cannot contribute to the stepper motor question as my knowledge is very limited on this, I just did not find any mention of such thing in the manual and assumed the bike does not come with one.
Coming back to the issue however, I think that @vintagehoarder must have had the point. I removed spark plug caps and spark plugs this morning for inspection. I am attaching the images of each. There is a significant difference in how they look. It's the left hand side cylinder which looks much more black/oxidised. More interestingly however is the fact that upon reassembly and starting up the bike again the spluttering, inconsistent idling and cut-offs have now gone.
So I am probably looking at an intermittent problem caused by the spark plug cables ...
(https://i.ibb.co/2ck80sn/IMG-9584.jpg) (https://ibb.co/2ck80sn)
(https://i.ibb.co/FgnqNSM/IMG-9582.jpg) (https://ibb.co/FgnqNSM)
I will try to search this forum for information about problems with this year models and see what I can find.
Fingers crossed.
I probably should have said at the start that I have had the unstable idle on cold starts since I purchased my Stone new in Dec 2012.
I had the factory map updated - no help.
I didn't do a Beetle map because that was (and remains) literally my only problem.
I don't THINK changing the spark plug caps changed anything (I ran the OEM ones till sometime in the last year). But the symptoms seem to vary with ambient temperature and humidity so that could have something to do with it in my (or our cases).
I don't know that I've ever had the high-rev thing happen, though now it makes me wonder if that's occasionally caused by the ECU attempting to compensate for the idle stumbles. < shrug >
I will say that I get why an intermittent cylinder misfire might cause an occasional stumble, but I don't think that has anything to do with the cold start stumble.
But again fingers crossed...
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So I am probably looking at an intermittent problem caused by the spark plug cables ...
(https://i.ibb.co/2ck80sn/IMG-9584.jpg) (https://ibb.co/2ck80sn)
(https://i.ibb.co/FgnqNSM/IMG-9582.jpg) (https://ibb.co/FgnqNSM)
I will try to search this forum for information about problems with this year models and see what I can find.
2013 is a single throttle body, right? Any chance the one cylinder's injectors are clogged to show such a difference in spark plugs, or maybe the plug gaps aren't set? Am I showing my lack of experience/knowledge?
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Those plug gaps both look big in the photos . did you re gap them before re installing? I think .027 is recommended.
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Those plug gaps both look big in the photos . did you re gap them before re installing? I think .027 is recommended.
Good eye Dave👍
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Those plug gaps both look big in the photos . did you re gap them before re installing? I think .027 is recommended.
Compared to the thread pitch the gaps look reasonable to me. They need to be wrong by a lot usually to create issues. The plugs do however look worn without a nice sharp edge on the centre electrode. They should be replaced. Probably wont help the issue but they need replacing anyway.
Phil
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Thanks for all the good advice.
I will be first of all changing the spark plugs. If you look close at the image below, there is a black residue/banding on the top of the spark plug where it connects to the plug cable. I wonder if this might be affecting the connection under certain temp/humidity settings thus causing the problem.
I will not be going down the route of changing plug cables at this stage.
(https://i.ibb.co/YtnWQFq/IMG-9585.jpg) (https://ibb.co/YtnWQFq)
I do however wonder as some of the posts here suggest, whether I have to personally adjust the plug gaps on the new spark plugs I receive ??
I mean, first of all I would not know how to do this and secondly I would assume that one of the numbers in the spark plug name (NGK CPR8EB-9 in this case), refers to the gap the plugs come with. Is it really the case that Moto Guzzi expects the owners to adjust the gap of the spark plugs when replacing them with the same exact model as OEM?
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Thanks for all the good advice.
I will be first of all changing the spark plugs. If you look close at the image below, there is a black residue/banding on the top of the spark plug where it connects to the plug cable. I wonder if this might be affecting the connection under certain temp/humidity settings thus causing the problem.
I will not be going down the route of changing plug cables at this stage.
(https://i.ibb.co/YtnWQFq/IMG-9585.jpg) (https://ibb.co/YtnWQFq)
I do however wonder as some of the posts here suggest, whether I have to personally adjust the plug gaps on the new spark plugs I receive ??
I mean, first of all I would not know how to do this and secondly I would assume that one of the numbers in the spark plug name (NGK CPR8EB-9 in this case), refers to the gap the plugs come with. Is it really the case that Moto Guzzi expects the owners to adjust the gap of the spark plugs when replacing them with the same exact model as OEM?
Lots of nope here.
As I've said, my 2013 has done this since new, with the original map, with an updated OEM map, with BRAND spanking new spark plugs, with new spark plug caps... the occasional cold start stumble for a few minutes till warm is the only symptom mine has ever had and it goes away as soon as it is warmed up.
Now why yours didn't seem to do it much before, I have no idea.
No I don't think that residue means jack. But then again I really don't believe that stumble is just an ignition misfire.
As for spark plugs, no, the gap is not in the code. The code is strictly about heat range (length of insulator), thread diameter, whether it's a resister plug or not etc. Though spark plugs often will be near or close to the correct gap when purchased, they are not designed for just one motor and therefore they might be wildly wrong. A simple wire feeler gauge is used to measure the gap, and it is adjusted by very VERY gently bending the side electrode that protrudes out to vary the gap.
But fresh plugs aren't going to hurt anything.
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Lots of nope here.
As I've said, my 2013 has done this since new, with the original map, with an updated OEM map, with BRAND spanking new spark plugs, with new spark plug caps... the occasional cold start stumble for a few minutes till warm is the only symptom mine has ever had and it goes away as soon as it is warmed up.
Now why yours didn't seem to do it much before, I have no idea.
No I don't think that residue means jack. But then again I really don't believe that stumble is just an ignition misfire.
As for spark plugs, no, the gap is not in the code. The code is strictly about heat range (length of insulator), thread diameter, whether it's a resister plug or not etc. Though spark plugs often will be near or close to the correct gap when purchased, they are not designed for just one motor and therefore they might be wildly wrong. A simple wire feeler gauge is used to measure the gap, and it is adjusted by very VERY gently bending the side electrode that protrudes out to vary the gap.
But fresh plugs aren't going to hurt anything.
Thanks for that Kev, message received. The way I see it it will be hard for me to pinpoint the problem since this seems to only occur on very rare occasions and disappears before I have the chance to put the diagnostic tool on the bike. As I said earlier, this time the problem stopped as soon as I took out the plug cables and put them back on again. Correlation is not causation of course, so I need to see if this will be relevant next time this happens.
On with changing the spark plugs then. I measured the gap on a pair of brand new ones and they come at 0.75mm. The user's manual says gap should be 0.6mm-0.7mm, so I guess 0.65mm is what I should be aiming at, right?
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Thanks for that Kev, message received. The way I see it it will be hard for me to pinpoint the problem since this seems to only occur on very rare occasions and disappears before I have the chance to put the diagnostic tool on the bike. As I said earlier, this time the problem stopped as soon as I took out the plug cables and put them back on again. Correlation is not causation of course, so I need to see if this will be relevant next time this happens.
On with changing the spark plugs then. I measured the gap on a pair of brand new ones and they come at 0.75mm. The user's manual says gap should be 0.6mm-0.7mm, so I guess 0.65mm is what I should be aiming at, right?
:thumb: Yup to everything. I hear ya!
If you ever really figure it out, let me know too. lol. :boozing:
On the plug if anything I tend to gap toward the lower end of the range more than the middle. The gap will widen in use and the bigger the gap the more resistance/harder the jump.
That said, I'm sure middle of the range is fine. I don't get the impression these ignition systems are underpowered or overstressed.
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I am nowhere qualified to offer any advice, since I have never owned any fuel injected bikes, but the fluctuating idle on any engine is usually associated with an air intake leak.
The ECU would then try to boost the fueling to compensate for the extra air going in. The sudden acceleration may be happening because, after parking the bike for awhile, the motor has cooled enough for the ECU to command a higher idle speed to warm up the motor. From the video, I can see that when the idle speed fluctuates, and throttle is applied, the response is very sluggish, typical of a very lean condition. The plugs appear to reflect this, as they are overly clean at the tips, at least one of them.
Could there be a crack or somewhere on the intake manifold where extra air is being sucked in?
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+1 Y'ep agree.
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The thing I see here over and over, are descriptions of anomalous behaviour that raise more questions than they attempt to answer.
When a bike is “idling poorly”, that raises the question…(s).
Is it idling correctly and dropping one cylinder momentarily ?
8 stroking due to excessive richness ?
Interruption to electrical supply?
“””””””””””””””””fuel supply?
Sticking valve(s) ?
And on and on……
I see that your left plug is darker, that to me suggests that excessive fuel is being supplied to that cylinder but it is (partially) burning it.
If the spark was failing, the plug would be wet, not black….sort of…
Also, although none of us would deny the need for a decent spark, once the microsecond of spark has come and gone, it’s the flame front that continues to promote the combustion.
A bit like lighting a wildfire with a small match or a large one, once you’ve started the fire it’s irrelevant how big the ignition source was…
I’d be looking at a malfunctioning injector.
Also, after watching your video..
Had you not pulled the camera back for a second or so, I’d have gained the impression that you were blipping the throttle.
Are you certain the idle is not controlled by a stepper ?
Notwithstanding any of the above. It’s highly significant that on a STB motor, you have differing combustion on either side.
I would not go for an air leak issue, or one plug would be good and the other one white (lean).
I’d be further tempted to swap the injectors over to the other sides and see if the dark plug moves to the right side, but do not swap the pugs. It will be worth seeing if the dark one cleans up and the good one goes black. :popcorn: :popcorn: :popcorn:
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And, I would not change the FI map until the problem is resolved first. Changing the map would not fix the issue; in fact, it would make the problem worse and harder to diagnose, with lots of head scratching and frustration.
Are there any vacuum hoses on the intake manifold that may be disconnected, damaged, etc.? Or a manifold gasket that does not completely seal?
Both cylinders seem to be firing, so, I would not suspect the plugs or plug wires to be the culprit.
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+1 Reason for my comments before on an Italian tune-up. Maybe the injectors need a cleaning.
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Or a manifold gasket that does not completely seal?
It’s a single throttle body, so that would affect both sides.
Even if it was the manifold gasket leaking, that would send it lean.
BTW.
Of the two plugs, which one is considered “normal” for gentle running ? I’m starting to wonder if the dark one is running ok and the light (right) one is failing from fuel starvation. When your bike quit suddenly at idle, it sounded like starvation.
Swap the injectors side for side and re check the pugs.
Also.
When the bike is surging from cold, put you hand on both headers and ascertain which one is “laying down…”Do some definitive diagnostics.
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I am nowhere qualified to offer any advice, since I have never owned any fuel injected bikes, but the fluctuating idle on any engine is usually associated with an air intake leak.
The ECU would then try to boost the fueling to compensate for the extra air going in. The sudden acceleration may be happening because, after parking the bike for awhile, the motor has cooled enough for the ECU to command a higher idle speed to warm up the motor. From the video, I can see that when the idle speed fluctuates, and throttle is applied, the response is very sluggish, typical of a very lean condition. The plugs appear to reflect this, as they are overly clean at the tips, at least one of them.
Could there be a crack or somewhere on the intake manifold where extra air is being sucked in?
Thing is, if it's like mine. It runs golden, almost perfect 99% of the time. It ONLY does it on some completely cold starts, for me, IIRC more likely in hot or humid conditions. And it only lasts for warmup and goes away within minutes.
Now I guess a mechanical air leak that only showed when it was say cold enough might make sense, except that I'm pretty sure mine occurs more often when ambient temps are hot.
Still it's a good suggestion if we can figure out why a leak might surface only once in a very long while.
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Are you certain the idle is not controlled by a stepper ?
Notwithstanding any of the above. It’s highly significant that on a STB motor, you have differing combustion on either side.
I would not go for an air leak issue, or one plug would be good and the other one white (lean).
See links I posted earlier it's a settled matter, the throttle body uses an integral stepper.
And as for air leaks, in theory I guess one could occur at the runner for that cylinder and not affect the other cylinder.
On the plugs, I'm not sure of the significance. EFI motors can go pig rich or crazy lean at the drop of a hat and plugs don't necessarily clean themselves of that. I was always told nothing but a plug chop can really tell you anything shy of the obvious (wet or oil fouled).
Of course the individual injectors and O2 sensors do mean there is some independent fueling so it is possible for one to run rich and the other lean relatively speaking. I'm just not convinced what we see is of any concern or causing the symptom.
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Thanks Kev.
So disarm the stepper and see what happens.
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Thanks Kev.
So disarm the stepper and see what happens.
If you do this it will almost certainly throw a MIL and won't idle.
Phil
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If you do this it will almost certainly throw a MIL and won't idle.
Phil
Well, leave it hooked up to the electrics and just plug the vacuum. The stepper will be oscillating, but won’t affect the idle mixture.
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Well, leave it hooked up to the electrics and just plug the vacuum. The stepper will be oscillating, but won’t affect the idle mixture.
The stepper is basically an ecu controlled idle air bypass valve. If you disconnect it then you have no idle control. With the single TB fitted I dont believe you can plug anything as it's all internal to the TB. The stepper "may" default to it's last position when disconnected, not sure.
Phil
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The stepper is basically an ecu controlled idle air bypass valve. If you disconnect it then you have no idle control. With the single TB fitted I dont believe you can plug anything as it's all internal to the TB. The stepper "may" default to it's last position when disconnected, not sure.
Phil
True, you will have no idle control while conducting the test, but you will either eliminate or highlight the stepper as the cause.
If the idle fluctuations disappear, then you know it was the stepper.
If it is all internal as you say unlike the big blocks…? Then either walk away or find the port that supplies the air bleed and disable it.
The whole aim is merely to see if it’s the stepper commanding the fluctuation.
When our OP’s bike quit at idle, it quit on both….(I think..)
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Ok, a couple of things.
* The stepper doesn't effect mixture per se, it effects volume. It's about increasing the amount of air and therefore idle speed so the engine doesn't stall on cold idle from too low an rpm. Mixture is still controlled by the ECM.
* You can't unplug it since it's internal. Guess you could find and block the idle passage as a test. But all that would do is confirm the hunting on cold starts is being caused by the ECM controlling the stepper and not WHY it is controlling it in that fashion (and we're 99.99% sure that's the case now).
* Maybe the biggest difficulty in troubleshooting this is the extreme intermittent nature (only happens during some cold starts) and once warned goes away completely.
Which is why after pursuing for a while nearly 10 years ago I said "screw it, I'll just let it warm up when it happens".
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I had a problem with my V7II - occasionally running on one cylinder. The cause of that could cause the problem you are having.
Cause: the fuel injector was plugged into the harness but the retaining clip was not properly installed. As a result it would occasionally lose connection and lose power. If that is happening on your bike it is then trying to recover by over-revving.
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Googling around points to bad O2 sensor or EVAP leak. Symptoms of EVAP leak are surging/stalling while driving.
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The stepper doesn't effect mixture per se, it effects volume. It's about increasing the amount of air and therefore idle speed
If the amount of air is being varied in isolation, then the air/fuel ratio (mixture), is changing as a function of the volume.
But rest assured, altering the volume of air and leaving the fuel flow static, is commanding the mixture.
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If the amount of air is being varied in isolation, then the air/fuel ratio (mixture), is changing as a function of the volume.
But rest assured, altering the volume of air and leaving the fuel flow static, is commanding the mixture.
Why would you assume the injector pulse width is static?
The same ECU that controls the injector pulse width is also controlling the stepper.
That's why I said "per se" the purpose of the stepper isn't to vary mixture, it is to control the volume entering past the plate and in doing so control speed. It's not to dilute the mixture.
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Why would you assume the injector pulse width is static?
The same ECU that controls the injector pulse width is also controlling the stepper.
That's why I said "per se" the purpose of the stepper isn't to vary mixture, it is to control the volume entering past the plate and in doing so control speed. It's not to dilute the mixture.
Ok Kev, the first statement was a bit of a word salad but yes, I see your assertion.
Enquires have been made…. :popcorn: :popcorn: :popcorn:
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Ok Kev, the first statement was a bit of a word salad but yes, I see your assertion.
Enquires have been made…. :popcorn: :popcorn: :popcorn:
Have a think about this. The injector pulse width is controlled primarily by 2 things, TPS angle and rpm with a bunch of trims added to that. So if the stepper opens and the rpm goes up even with the TPS static the pulse width will change because the RPM increases.
Phil
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Well I have had a think since you asked me to.
The pulse width determines the amount of fuel per squirt I guess. That amount is determined by the needs of the engine at that moment and you’ll be bound to admit that the need is a function of rpm and throttle setting…
So.
Just because the revs increase, it does not mean that it is demanding more fuel.
Going downhill at 5000 rpm is using a lower throttle setting than going uphill at 3,500.
So linking fuel flow to rpm solely is not a legitimate line of thought…? :popcorn: :popcorn: :popcorn:
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Well I have had a think since you asked me to.
The pulse width determines the amount of fuel per squirt I guess. That amount is determined by the needs of the engine at that moment and you’ll be bound to admit that the need is a function of rpm and throttle setting…
So.
Just because the revs increase, it does not mean that it is demanding more fuel.
Going downhill at 5000 rpm is using a lower throttle setting than going uphill at 3,500.
So linking fuel flow to rpm solely is not a legitimate line of thought…? :popcorn: :popcorn: :popcorn:
Who said the demand or fuel flow increased?. The needs of the engine are determined by the guy that writes the map in reality that's why there are good and bad maps. Some map writers determine badly. Then that's enhanced by the trims. Here's a fuel map for a Centauro, note the pulse width reduces as the revs rise and the throttle angle stays the same for the majority of the map. The original point is the fuel flow changes with rpm in isolation so if the stepper motor creates greater rpm without obviously changing the throttle angle then the FF will change also. That last statement is an overreach in reality as I dont actually know if the systems that use a stepper actually have a link between fuel and stepper position. I'm hanging my arse out there in the breeze:)
(https://i.ibb.co/Br4h3N6/Screenshot-2021-06-23-145739.png) (https://ibb.co/Br4h3N6)
Phil
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I’m leaving this alone now because it’s contaminating the thread.
Maybe one day we’ll pick it up, too hard on here.
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........
As for spark plugs, no, the gap is not in the code. The code is strictly about heat range (length of insulator), thread diameter, whether it's a resister plug or not etc. .....
Kev I wouldn't normally disagree but in this case the CPR8EB-9 plugs are special
Go here https://online.flippingbook.com/view/17923346/4/ Page 4
Where it says if marked -9 they come gaped at 0.9mm (no marks is 0.7 - 0.8mm)
That being said My V9 manual says it should be 0.7mm IIRC, which puzzles the heck out of me as to why MG buy a plug from NGK gaped at 0.9mm
I'm sure that the chap on the shop floor building the bike isn't re-gaping all the plugs :undecided: :undecided: :undecided:
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Well I have had a think since you asked me to.
The pulse width determines the amount of fuel per squirt I guess. That amount is determined by the needs of the engine at that moment and you’ll be bound to admit that the need is a function of rpm and throttle setting…
So.
Just because the revs increase, it does not mean that it is demanding more fuel.
Going downhill at 5000 rpm is using a lower throttle setting than going uphill at 3,500.
So linking fuel flow to rpm solely is not a legitimate line of thought…? :popcorn: :popcorn: :popcorn:
To clarify pulse width = time = the total amount of times the injector is actuated for a given intake cycle. Injectors don't just sit open, they are rapidly opened/closed to spray fuel.
Your logic is slightly faulty logic because you focused only rpm changing in your example but forgot the throttle changed too. So it's not the same as an example when the throttle doesn't change but rpm does.
Fuel is linked to speed/density - to rpm and throttle position and a change to one will change it, though I think throttle has a bigger effect. Either way, fuel is a function of both, a table of varied values based on the intersection of the particular row/column right?
If you close the throttle you've changed a variable (shifted one row or column). So going downhill with a closed throttle at 5000 rpm puts you on a different place on the table than going downhill with the throttle OPEN at 5000 rpm - that would have a lot more fuel.
Closed throttle and running at say 2000 rpm vs 1000 rpm there is going to be a little more fuel at the higher rpm, again two different places on the table.
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Who said the demand or fuel flow increased?. The needs of the engine are determined by the guy that writes the map in reality that's why there are good and bad maps. Some map writers determine badly. Then that's enhanced by the trims. Here's a fuel map for a Centauro, note the pulse width reduces as the revs rise and the throttle angle stays the same for the majority of the map. The original point is the fuel flow changes with rpm in isolation so if the stepper motor creates greater rpm without obviously changing the throttle angle then the FF will change also. That last statement is an overreach in reality as I dont actually know if the systems that use a stepper actually have a link between fuel and stepper position. I'm hanging my arse out there in the breeze:)
(https://i.ibb.co/Br4h3N6/Screenshot-2021-06-23-145739.png) (https://ibb.co/Br4h3N6)
Phil
Ha ha - great post. It reminds me that even thinking about this in two dimensions allows us to oversimplify.
If I'm reading that map right it looks like that map actually leans the mixture as rpm goes up if the throttle angle remains the same.
What it doesn't tell us is how rich it is to begin with, and why it leans. Isn't the hottest/strongest mixture point generally leaner than stochiometric? Does this map run richer at lower speeds to reduce temperatures?
And how is this map effected by correction factor for temperature, the OPs condition is cold idle right? Warm up gets a richer mixture based on cylinder head temp.
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Kev I wouldn't normally disagree but in this case the CPR8EB-9 plugs are special
Go here https://online.flippingbook.com/view/17923346/4/ Page 4
Where it says if marked -9 they come gaped at 0.9mm (no marks is 0.7 - 0.8mm)
That being said My V9 manual says it should be 0.7mm IIRC, which puzzles the heck out of me as to why MG buy a plug from NGK gaped at 0.9mm
I'm sure that the chap on the shop floor building the bike isn't re-gaping all the plugs :undecided: :undecided: :undecided:
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Thanks for the correction and education. I missed that -# in the tables I've looked at in the past!
Cheers!
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No I don’t Kev, but it’s just too damn hard to keep on correcting people who unintentionally misrepresent what I say.
So, have a nice day… :thumb:
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No I don’t Kev, but it’s just too damn hard to keep on correcting people who unintentionally misrepresent what I say.
So, have a nice day… :thumb:
I'm not intentionally misrepresenting anything.
If you think that, then I don't know what you mean (whether that's my misunderstanding or your not expressing it well, could be two peoples divided by a common language).
Did you get my point on closed throttle vs. open throttle at same RPM = different fuel and why?
And how that is different from same throttle and different rpm?
And how temperature and cold starts also changes the equation.
And any other logic in any given map we don't know about/haven't considered yet?
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Ok, I swore I wouldn’t do this but anyway.
Whatever the stepper does or does not do, is not where I wanted to go. I was just speculating that the stepper may be not smooth enough in it’s operation and failing to make the miniature adjustments required to stabilise the idle.
All I wanted was to get to the bike while it was hunting and disconnect the stepper and see what if any, the immediate effect was.
If the symptom immediately alters, then it’s the stepper.
What then…?
Dunno.
But it’s targeting the cause.
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Ok, I swore I wouldn’t do this but anyway.
Whatever the stepper does or does not do, is not where I wanted to go. I was just speculating that the stepper may be not smooth enough in it’s operation and failing to make the miniature adjustments required to stabilise the idle.
All I wanted was to get to the bike while it was hunting and disconnect the stepper and see what if any, the immediate effect was.
If the symptom immediately alters, then it’s the stepper.
What then…?
Dunno.
But it’s targeting the cause.
Copy that.
Agreed that's logical and good troubleshooting.
Unfortunately not practical since it's integrated and there's no connector to unplug.
I will note that I had some Guzzi gurus think/troubleshoot this 10 years ago when I discovered it on my 2013 and because it was somewhat intermittent (seemingly but not verified that is varied with ambient conditions), but then went away completely within minutes (after warmed a bit) we gave up and moved on.
My bike does this on most cold starts to this day, and then runs flawlessly the rest of the day (unless I stop long enough for it to cool significantly, and then it's just another 3 minutes or so till it's gone).
Now why the OPs does it much less often? Ambient conditions might be it, or it might be a different unrelated fault, maybe a loose connector, but that doesn't seem to fit my pattern.
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Work with me a bit
I've just reread this thread and listened to the engine running at part of me says if a carb engine was doing that I'd adjust the idle mixture screw until it didn't.
Obviously we can't do that ourselves with these bikes, idle is controlled by the ECU with the stepper adjusting the air to achieve the target idle
If the stepper was faulty, then it might manifest itself as a hunting idle .
Does GDiag allow you to stroke the stepper on this ECU as you can on the CARC bikes?
Might eliminate the stepper if it does
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Just give me 1 minute of your lives, watch this and listen to what it does @ the 20 second mark..
https://youtu.be/Li8qvFVuAJ8
Is our OP’s bike the same ?
It then settles into a perfect idle..(and it’s not as loud as it sounds on video).
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Just give me 1 minute of your lives, watch this and listen to what it does @ the 20 second mark..
https://youtu.be/Li8qvFVuAJ8
Is our OP’s bike the same ?
It then settles into a perfect idle..(and it’s not as loud as it sounds on video).
OP will have to answer for himself (though I think his video sounds very similar).
I'll say YES, that sounds almost identical to what my 2013 does on most cold starts (and that my 2018 has NEVER done).
Follow up question - if you attempt to ride away when it's doing that, what happens?
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Ummm, I don’t know Kev but next time I can I will.
I can tell you that a blip on the throttle will override the symptom as it’s occurring.
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Ummm, I don’t know Kev but next time I can I will.
I can tell you that a blip on the throttle will override the symptom as it’s occurring.
When this occurs on mine you can try to throttle out of it, but the second you slip the clutch and apply any load it will die.
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When this occurs on mine you can try to throttle out of it, but the second you slip the clutch and apply any load it will die.
Ok.
By the time I’ve put my gloves on and closed the garage door, it’s perfect.
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Ok.
By the time I’ve put my gloves on and closed the garage door, it’s perfect.
Could be similar.... I've got gravel so I have not done that and I'm seated by the time I start it. :boozing:
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Just give me 1 minute of your lives, watch this and listen to what it does @ the 20 second mark..
https://youtu.be/Li8qvFVuAJ8
Is our OP’s bike the same ?
It then settles into a perfect idle..(and it’s not as loud as it sounds on video).
I'll tell you what that is, it's caused by fuel puddling in the inlet manifolds with a rich start mixture and a cold engine. So the fuel puddles and periodically the engine sucks it in and goes rich and stumbles. Once the engine gets some temp into it and the manifolds heat up and the fuel stops puddling and the cold engine and start trim leans out a little they settle down. Giving the throttle a quick twist to keep it going just adds fuel and doesn't help. My V10 Sport does it as well and having the high idle lever set at a slightly higher rpm helps until it's warmed up a little.
Phil
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Just give me 1 minute of your lives, watch this and listen to what it does @ the 20 second mark..
https://youtu.be/Li8qvFVuAJ8
Is our OP’s bike the same ?
It then settles into a perfect idle..(and it’s not as loud as it sounds on video).
Sounds like my V9.
Start bike and lid and gloves on all good
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I'll tell you what that is, it's caused by fuel puddling in the inlet manifolds with a rich start mixture and a cold engine. So the fuel puddles and periodically the engine sucks it in and goes rich and stumbles. Once the engine gets some temp into it and the manifolds heat up and the fuel stops puddling and the cold engine and start trim leans out a little they settle down. Giving the throttle a quick twist to keep it going just adds fuel and doesn't help. My V10 Sport does it as well and having the high idle lever set at a slightly higher rpm helps until it's warmed up a little.
Phil
Thanks for that Phil.
I didn’t know what it was.
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I'll tell you what that is, it's caused by fuel puddling in the inlet manifolds with a rich start mixture and a cold engine. So the fuel puddles and periodically the engine sucks it in and goes rich and stumbles. Once the engine gets some temp into it and the manifolds heat up and the fuel stops puddling and the cold engine and start trim leans out a little they settle down. Giving the throttle a quick twist to keep it going just adds fuel and doesn't help. My V10 Sport does it as well and having the high idle lever set at a slightly higher rpm helps until it's warmed up a little.
Phil
:thumb: that makes sense...