V11 surging and pinging related?

[Doansci]

Hello,

2002 LeMans with 15M computer.  A hot engine surges at small throttle openings just off idle up to at least 4,000 rpm.  Also when hot the engine will ping accelerating hard from 4500 rpm to 5500 or higher in 4th gear.  I'm trying to understand how these symptoms are related but need someone to double check my thinking.

The 15M computer has a preloaded fuel mixture and spark advance map so fuel delivery and timing are not adjustable independently - correct?  The start or "bottom" of the fuel map is closed throttle and as the throttle opens the computer increases the fuel proportional to throttle opening - correct.  While the start or "bottom" of the ignition advance curve is 0 rpm and probably reaches maximum advance by about 2,500 rpm - correct?  (was not able to find a timing curve on the forum)

If the above are correct, then setting the TPS too far one way would move the starting point further up the fuel map so that the computer would provide more fuel than a correct TPS setting (computer thinks the throttle is open further than it is) while setting the TPS too far the other way would provide less fuel than a correct TPS setting (computer thinks the throttle is open less than it is).

Because timing is predetermined by the ignition map, pinging under hard acceleration indicates the mixture is too lean at large throttle openings - correct?  So surging at low throttle openings would likewise be due to lean mixture.  Does this logic make sense?  (provided all the sensors and computer are working correctly)

Thank you!

 

 

[docc]

 While "this logic makes sense", trying to index the throttle opening to a random point on the mapping, simply to add more fuel, leads to other undesirable issues.

Most proven method is to baseline the critical parameters at the outset:

 

[audiomick]

29 minutes ago, Doansci said:

... Does this logic make sense? ...

As far as I know, yes, mostly.

The pinging might perhaps also have to do with inferior quality fuel.

On top of "all the sensors and computer are working correctly" there is making sure that there are no air leaks between the throttle bodies and the cylinder. That could make a good map run lean.

The big question is, however, have you done everything in the "decent tune up"?

 

If you haven't made absolutely sure that all the basic stuff is right, you are shooting at a moving target trying to find out what is not right.

 

Edit: bugger, docc was faster. How does he do that?

Edited July 25 by audiomick

[Lucky Phil]

Before you start overthinking it which it sounds like you are make sure the fuel filter isn't blocked/dirty and the TB's are not popped off and the manifold rubbers aren't leaking. Move onto the TPS and tuning after that unless it's needed for some reason you haven't mentioned. 

Edited July 25 by Lucky Phil

[Doansci]

Thank you all.  Yes, 92 non-ethanol fuel is the best we can do here. 

Late last summer I did the decent tune-up starting with valve adjust etc.  It made a remarkable difference with the surging and stumbling off idle but didn't eliminate it completely.  Biggest difference was cleaning the bypass screws, resetting the TPS, balancing the throttle bodies and lowering the idle. It's only been about 1,000 miles since the tune and the symptoms have gotten worse as the temperature has increased so thinking there is more to do.

[Doansci]

New manifold rubber sleeves last year.  Fuel filter was replaced about 8,000 miles.  Now has 25,000 miles.  

[audiomick]

1 minute ago, Doansci said:

...thinking there is more to do.

yes, I'm in the same boat. My 2002 Le Mans spits and coughs between 2 and 3 thousand rpm at constant throttle when it is warm. I did go through the "decent tune up", but in a hurry. I think I need to go at it again in a relaxed and concentrated manner. Also, I have ordered a new sensor for the motor position. Don't know what it is called in English. The German name is "phasen sensor". I've heard that they give up after a while, and someone provided me with a source for an affordable price, so I will swap it out and see what it brings.

[Doansci]

33 minutes ago, docc said:

 While "this logic makes sense", trying to index the throttle opening to a random point on the mapping, simply to add more fuel, leads to other undesirable issues.

 

Was thinking that if TPS was correct, but the map was in the wrong places it might point to which sensors to check. 

[Doansci]

2 minutes ago, audiomick said:

yes, I'm in the same boat. My 2002 Le Mans spits and coughs between 2 and 3 thousand rpm at constant throttle when it is warm. I did go through the "decent tune up", but in a hurry. I think I need to go at it again in a relaxed and concentrated manner. Also, I have ordered a new sensor for the motor position. Don't know what it is called in English. The German name is "phasen sensor". I've heard that they give up after a while, and someone provided me with a source for an affordable price, so I will swap it out and see what it brings.

Phasen sensor is timing sensor on front of engine over cam gear?  What was your source?

[audiomick]

Just now, Doansci said:

Was thinking that if TPS was correct, but the map was in the wrong places...

That is kind of self-contradicting. The map is a given, assuming the manufacturer is not completely stupid. If the TPS is correct, the ECU is getting the correct data that it needs to implement the (theoretically correct) map correctly, and everything should be sweet.

If one assumes that the map is good, which one must to an extent, then irregularities point to something not working the way it should (sensors, bad fuel, leaky rubbers, whatever).

As pointed out further up, not only by me, the first thing is to make absolutely sure that all the basic stuff is definitely ok. If that is not done, its a wild goose chase.

[audiomick]

19 minutes ago, Doansci said:

timing sensor... What was your source?

I was provided with these links:

https://www.autoteile-markt.de/shop/artikel/impulsgeber-kurbelwelle-facet-9.0032-d1a862c35a20ef761692aff82f023960?gclid=EAIaIQobChMIs5fjzLGh_AIVh-93Ch3pew71EAQYASABEgIqrPD_BwE

https://www.pkwteile.de/facet/2181912

https://www.autodoc.de/facet/2181912

I ordered the one from the first link because it was the cheapest. I can't say anything at all about the quality or compatibility. Mine hasn't arrived yet, so I am working on hearsay at this point. However, I trust implicitely the person who sent me the links. He used to work in a Guzzi workshop, was perhaps the owner, and knows an awful lot about the 1100 Sport/ Sport 1100/ Daytona/ V11 period of the Guzzi history.

EDIT: to put the price in perspective, this is the original Guzzi part:

https://wendelmotorraeder.de/phasen-und-umdrehungsfuhler_gu01721600-p-1024014.html?ref=expl

 

ANUVVEREDIT: the links are for suppliers in Germany, which is good for me because that is where I live. Rather than ordering from Germany, I would suggest searching for a supplier for the sensor FACET 9.0032 in your country. I gather it was used in a number of vehicles, and should be able to be found.

 

 

 

Edited July 26 by audiomick

[guzzler]

Guy's

It's important to get the right gap for the Timing sensor as well.

I did have mine adjusted with correct spacers early in the caper when she was doing what your bikes are doing.Several other things were replaced at same time so can't pinpoint this as sole issue but do remember others having these issues with it when trying to diagnose my problems. 

Too little or too much gap will cause running issues!

There is info on it on here but will dig it out for you if needed...

Cheers   

[docc]

34 minutes ago, Doansci said:

Thank you all.  Yes, 92 non-ethanol fuel is the best we can do here. 

Late last summer I did the decent tune-up starting with valve adjust etc.  It made a remarkable difference with the surging and stumbling off idle but didn't eliminate it completely.  Biggest difference was cleaning the bypass screws, resetting the TPS, balancing the throttle bodies and lowering the idle. It's only been about 1,000 miles since the tune and the symptoms have gotten worse as the temperature has increased so thinking there is more to do.

Including throttle body balance at "some rpm?"

I also have learned (the hard way) that the TPS baseline can be painfully elusive. Worth repeating with absolute certainty the throttle pate is "completely closed."

Cleaning and treating (Caid DeOxit®) the sensor connectors can be helpful while assessing the values of various sensors on GuzziDiag from cold start to operating temperature could reveal a failed sensor.

[guzzler]

Fella's.

I just checked back through my records...

My Phase sensor was at 1.4 mm (way out) and reduced to 0.7 mm back in 2011.

From memory the gap should be 0.6 or 0.7!

I also had a crap standard timing chain tensioner replaced at the time which probably contributed to my issues.. but make sure the Phase sensor has correct gap as above.

Cheers 

  

 

[gstallons]

AND make sure one of the teeth is in the center of  the crank sensor bore . This is critical amd you want to get it right the !st time. You don;t want it close , you want it right.