V11 Sneeze

[MartyNZ]

So Guzzidiag sets the CO, 

how does that work there is nothing in the ECU to measure O2 or CO

I thought you would need to be hooked up to a fancy analyzer.

You're right, to do things properly on an engine without a Lambda sensor (like yours and mine), you should know the CO level in the exhaust. You might guess on the CO using you nose, looking at plugs, or noticing uneven running, but regardless, GuzziDiag allows you to set the CO trim. 

See the last few pages of http://www.thisoldtractor.com/moto_guzzi_quota_guzzidiag_howto_-_a_tutorial_for_beginners.html

Your question is answered here: http://wildguzzi.com/forum/index.php?topic=65527.0

Other good stuff is here: http://www.von-der-salierburg.de/download/GuzziDiag/

and here: http://www.tunerpro.net/downloadApp.htm

[Kiwi_Roy]

Ok, I see you adjust the CO trim for  good idle, thanks for pointing out the great information.

 

For homework tonight I measured the sensor gap with a bead of JBQuick on the sensor, bang on 0.7mm so that's at the lower limit

As an exercise I may pack it out to 0.9 to see if it makes any difference

 

BTW the sensor on my bike is Magnetti Marreli SEN 813

[czakky]

The way I understand it is the CO is just a very small additional amount of fuel to the mix for the whole rev range.

 

The ECU on early (pre 02 I think) V11s have no CO/Lambda sensor, thus no reading of the fuel mixture.

 

I know some guys have set there CO with a sniffer but with Guzzidiag I think it's much easier.

[docc]

True that an exhaust gas analyzer is the correct method. Andy used that and, at the time, VDSTS to set mine.  I suppose it was just coincident that the analysis was correct at the CO "setting" of zero.

 

The idle did smooth out noticeably and rose a couple hundred RPM.

[stewgnu]

Interesting. I've just had a slightly low, grumpy idle manifest itself. She usually idles happily around 1100-1200 but lately she sometimes bimbles around 900. This along with some popping when decelerating to a stop and becoming more difficult to ride smoothly a low speeds. Only thing i've messed with recently are the 'bars so i wonder if the issue lies there, like JB mentions. I'd thought i had groomed the cables really well but possibly a re-check is in order.

 

I too was thinking exhaust leak? Inlet wubbers??

[Antiquar]

I  struggled  sooo  many  years  with  burping/hiccup/sneeze  before  a  Total Expert and Complete Gentleman  (The Perfesser-His-Own-Self Andy York) zeroed my CO. It was an absolute revelation. Mine was at "minus 27."

 

Wow, -27.

 

My CO trim was at 0 but bumping it to +5 cured my V11's sneeze. Since then I've dropped it to +3 in a vain attempt to increase fuel efficiency. At +3 I will get a very rare sneeze, but much better than it was at 0.

 

I have some slight cracks in the intake rubbers, so I may try the electrical tape trick for the moment.

[docc]

One of my sputters turned out to be a TPS with a single bad spot on it. I couldn't find it reading millivolts on my digital DVOM, but reading resistance while slowly opening and closing the throttle, I could see a*jump* in values (Ohms). It was, of course, just off idle where the TPS apparently spends most of its time.

[Kiwi_Roy]

One more thing to check

I will go through the TPS setting and balance over the weekend.

[Cliff]

Hi Roy

 

I tried to send this as a private message but it said you weren't able to receive private messages.

 

I'm surprised to see this thread from you. It sounds like you have not been doing much tuning with the MyECU.

Please let me know if you are having issues.

Regards

Cliff

[Kiwi_Roy]

Cliff, the bike has been parked for over a year.
No, the MyECU has been flawless, it's only recently been suggested that perhaps the CO needs resetting.

 

For the longest time I assumed it was getting an odd pulse from say the phase sensor causing it to fire earlier, most unlike a mixture issue.

 

The bike runs so nice apart from the sneeze at idle, gobs of power and good fuel economy, Again to describe the symptoms.
Idles nicely then after 30 or 40 pulses gives a violent pulse that seems to stop the engine in it's tracks, I equate this to firing well before TDC and trying to change direction.

 

I have been sidetracked for the last year or two by some mature older ladies.
84 California II, 72 Eldorado, 86 Lario

 

[docc]

If I had V11 acting up, I would start with:

 

1) zero the CO (sure, use an exhaust-gas analyzer if you've got one)

2) baseline the TPS

 

Then, the best and easy stuff:

1) fresh spark plugs

2) Adjust the valves

3) Balance the throttle bodies

4) Fresh zero-ethanol premium fuel (finding such could be like adding melted dragon's teeth to the fork oil . . .)

 

Sure, there's a chance that some component has played up. Or the mapping is just terrible. But those aren't the most likely suspects.

[GuzziMoto]

I think there is more than one possible cause of the dreaded V11 sneeze.

I remember it being suggested that one possible cause was the weak stock cam chain tensioner. Perhaps at certain rpms the tensioner is not able to keep the timing in check.

Some people upgraded to a better tensioner or even gears and reported the sneeze went away. But, as I said, there is likely more than one cause and as such there is likely more than one solution.

I recall having also heard people say that they set their valve clearances to a given value and the issue was reduced or went away. Often that value is higher than the standard US clearance numbers in the manual, sometimes what is referred to as the "world" clearance specs.

 

I have bought a set of gears for the wifes V11. It has a minor case of the sneeze, so I will see what, if any, effect that has on it. That is, of course, when I finally get around to installing the gears. It turns out keeping them in a box near the bike has no effect.

[JBBenson]

Cliff, the bike has been parked for over a year.

No, the MyECU has been flawless, it's only recently been suggested that perhaps the CO needs resetting.

 

For the longest time I assumed it was getting an odd pulse from say the phase sensor causing it to fire earlier, most unlike a mixture issue.

 

The bike runs so nice apart from the sneeze at idle, gobs of power and good fuel economy, Again to describe the symptoms.

Idles nicely then after 30 or 40 pulses gives a violent pulse that seems to stop the engine in it's tracks, I equate this to firing well before TDC and trying to change direction.

 

I have been sidetracked for the last year or two by some mature older ladies.

84 California II, 72 Eldorado, 86 Lario

 

 

 

"Idles nicely then after 30 or 40 pulses gives a violent pulse that seems to stop the engine in it's tracks, I equate this to firing well before TDC and trying to change direction."

 

I had this EXACT symptom. It DID feel like the engine was almost trying to run backwards, sometimes with a weird clunk or banging sound.

 

It was solved by doing what Docc prescribes above, although I didn't do the CO trim, and we don't have ethanol free gas here, so I used Redline SL-1 fuel system cleaner to get any crud out.

 

I would add: check intake rubbers for cracks, and make sure there are no exhaust leaks. The V11 is weirdly sensitive to exhaust leaks.

[Kiwi_Roy]

I think there is more than one possible cause of the dreaded V11 sneeze.

I remember it being suggested that one possible cause was the weak stock cam chain tensioner. Perhaps at certain rpms the tensioner is not able to keep the timing in check.

Some people upgraded to a better tensioner or even gears and reported the sneeze went away. But, as I said, there is likely more than one cause and as such there is likely more than one solution.

I recall having also heard people say that they set their valve clearances to a given value and the issue was reduced or went away. Often that value is higher than the standard US clearance numbers in the manual, sometimes what is referred to as the "world" clearance specs.

 

I have bought a set of gears for the wifes V11. It has a minor case of the sneeze, so I will see what, if any, effect that has on it. That is, of course, when I finally get around to installing the gears. It turns out keeping them in a box near the bike has no effect.

You may have mentioned this to me before, It certainly made sense that the chain could have been whipping around so I replaced the old tensioner with one of the blade type and  new chain for good measure.

It had no effect on the sneezing but certainly gave me less things to worry about, that old tensioner was crude to say the least.

[Kiwi_Roy]

 

 

"Idles nicely then after 30 or 40 pulses gives a violent pulse that seems to stop the engine in it's tracks, I equate this to firing well before TDC and trying to change direction."

 

I had this EXACT symptom. It DID feel like the engine was almost trying to run backwards, sometimes with a weird clunk or banging sound.

 

It was solved by doing what Docc prescribes above, although I didn't do the CO trim, and we don't have ethanol free gas here, so I used Redline SL-1 fuel system cleaner to get any crud out.

 

I would add: check intake rubbers for cracks, and make sure there are no exhaust leaks. The V11 is weirdly sensitive to exhaust leaks.

 

Yes exactly that.

I started going through Docc's check list, the TPS was quite a way out, how do those move?

 

I have a wideband O2 sensor, that's no use for setting the O2 is it?