Author Topic: The problem with single throttle body V7's  (Read 23287 times)

beetle

  • Guest
The problem with single throttle body V7's
« on: January 29, 2017, 01:12:32 AM »
For those who have the cold start/stumble issue with your 1TB V7, the cause is the ECU. The TPS is built into the MIU G3 and is not serviceable. It uses an analogue incremental encoder for the TPS, and in the case of the MIU G3, there is a gap or 'jump' in the TPS values when opening the throttle. Typically, it will jump from 1.8 to ~12.4 degrees when the engine is not running. That's approx 2% to 15% throttle. When the engine is running, the jump is reduced to around 1.8 to ~8.4 degrees (2% to 10% throttle).  I'm not sure what the cause is, but I suspect a poor choice of ADC, as the the output voltage from the encoder is linear.

When the engine is cold (<40C) the engine will stall, as when you blip the throttle, it will take a big gulp of air, but there may not be enough fuel for the cold engine, so it's stalls. As the engine warms up, the amount of fuel required is reduced, so the affect is negligible. I believe the affect is exacerbated with aftermarket mufflers, as the extra flow requires even more fuel.

I believe Marelli are aware of this, and their workaround is to squirt more fuel in that problem area when the engine is cold. Have a look at the fuel-engine-temperature correction table for the stock V7-II.




Notice the workaround? It's a kludge.


OK, I'm open to sledging, haters, know-it-alls and the fine gentlefolk to comment, harangue or otherwise provide comment.

pete roper

  • Guest
Re: The problem with single throttle body V7's
« Reply #1 on: January 29, 2017, 02:00:13 AM »
As I've said before with regard to other fueling options, anything will run if you throw lots of fuel at it. It just won't run very well, will cause more pollution and will use an excessive amount of a precious and finite natural resource. In this case it only does it until it's out of the critical warm up period so it doesn't have time to foul plugs and stuff but it's still a sucky way of going about things. Must be cheap for them though..... :rolleyes:

Pete

oldbike54

  • Guest
Re: The problem with single throttle body V7's
« Reply #2 on: January 29, 2017, 02:23:53 AM »
 Well that just sux 👎

 Dusty

Hymes Inc.

  • Guest
Re: The problem with single throttle body V7's
« Reply #3 on: January 29, 2017, 02:39:03 AM »
My 2013 special is not friendly when cold. I've been pondering getting a beetle map for it.

Wildgoose Chase Moto Guzzi

Re: The problem with single throttle body V7's
« Reply #3 on: January 29, 2017, 02:39:03 AM »

beetle

  • Guest
Re: The problem with single throttle body V7's
« Reply #4 on: January 29, 2017, 02:58:04 AM »
I've eliminated it from the stock V7 (Pete's Racer) and am now tweaking the map. Craig (Clancy on the forum) is testing the fix on a stock V7-II. There will be a few updates to that map before I make it available, so I'd suggest waiting until I've sorted both V7 I &vII.

Offline waxi

  • The light at the end of the tunnel has been turned off due to budget cuts.
  • Weekend Warrior
  • ***
  • *
  • *
  • Posts: 293
  • Location: Slovenia, Europe
Re: The problem with single throttle body V7's
« Reply #5 on: January 29, 2017, 05:07:47 AM »
Let me know if I can help. We still have winter here, but in March this snow should go away.
Moto Guzzi V7 II Special, 2015
Moto Guzzi Nevada, 1998
Tomos Automatik A3 ML, 1987, oldtimer

Offline stevet

  • Guzzi Hero
  • *****
  • Posts: 2112
  • What would Mr. Happy Puppet do?
Re: The problem with single throttle body V7's
« Reply #6 on: January 29, 2017, 09:26:07 AM »
Thanks to Beetle, Pete, and Clancy and others for being out front on this matter and putting forth expertice and experimentation to get our machines running better.  It's a shame the OEM's can't, won't, do the right thing and do things right from the beginning.  (How much more effort and cost can it take to write a proper computer program vs. accepting an improper program?) I am waiting to see the fruits of your efforts, then I'll jump in, contributing to the support of your efforts.  Well done, Mates!

Steve.
Steve T.
Twin Cities, MN
Sophia, '16 Moto Guzzi V7 II Stone
Feejer, '10 Yamaha FJR
"Il Viaggiatore", The Traveler. A.K.A. Via. 2017 FIAT 124 Spider Classica

"What we do during our working hours determines what we have; what we do during our leisure hours determines what we are."
-George Eastman.

Offline Aaron D.

  • Guzzi Hero
  • *****
  • Posts: 5850
Re: The problem with single throttle body V7's
« Reply #7 on: January 29, 2017, 10:34:29 AM »
Well, there it is. This issue cost Guzzi a sale, when I took out a new V7 in 2015. I found the bad fueling totally unacceptable on the bike I tested.

Offline Andy1

  • Sunday Rider
  • **
  • Posts: 166
  • Location: UK
Re: The problem with single throttle body V7's
« Reply #8 on: January 29, 2017, 10:39:13 AM »
Hi Beetle, can you explain that Table please?  (Nice and simply for me!)
Not sure what the top axis is, and I guess the vertical axis is temperature - ambient?  airbox?  Guess in F but goes down very cold?
Thanks
Andy1

beetle

  • Guest
Re: The problem with single throttle body V7's
« Reply #9 on: January 29, 2017, 02:17:57 PM »
Horizontal is TPS. Vertical is engine temperature in degrees Celsius. Each cell is a correction value applied depending on measured engine temp versus throttle position. The ECU interpolates the values, so the correction won't be the exact value of the cell.

Notice the values above idle at 60C and warmer are all the same? That means that as the engine reaches max operating temp, the fuel is not corrected properly for best running. I doubt you'd ever see a V7 engine hit 125C, but it's still not right.


The other thing that bugs me is the main fuel maps. Have a look at the right cylinder map. Can you see what's wrong here?




Offline Andy1

  • Sunday Rider
  • **
  • Posts: 166
  • Location: UK
Re: The problem with single throttle body V7's
« Reply #10 on: January 29, 2017, 02:53:52 PM »
So the first table shows that there is no compensation of the a/f ratio once the engine temp (how is engine temp defined?) is over 60C.  Not sure what this has got to do with cold running issues?   Sorry, not trying to start a fight, just trying to understand the figures.
To me the table says that the mixture is enrichened at lower temperatures (good).  I guess that the enrichment is not enough to stop the cold stumble.

Table 2.  Sorry, I need to know what the figures in the boxes are.  Vertical axis is RPM, Horizontal is TPS.
The error is perhaps that the figures peak mid rpm range at larger TPS values, rather than peaking at min rpm as at lower TPS values....which I suspect gives a rich mixture mid-range????

Andy1


 
« Last Edit: January 29, 2017, 02:54:40 PM by Andy1 »

Offline Andy1

  • Sunday Rider
  • **
  • Posts: 166
  • Location: UK
Re: The problem with single throttle body V7's
« Reply #11 on: January 29, 2017, 02:56:02 PM »
How can the map run to 8250rpm when the rev linmiter cuts in around 7250?

Offline Clancy

  • Weekend Warrior
  • ***
  • Posts: 246
  • Location: Canberra, Down Under
Re: The problem with single throttle body V7's
« Reply #12 on: January 29, 2017, 03:01:56 PM »
I've had the V7-II out 3 times with the latest map.
That's 3 cold starts, although 'cold' at the moment is in the low 20's*C air temp....
(Yesterday I did 300k's with air temps over 35*C - a little sweaty  :rolleyes:)

I'll be commuting on the bike all week, so will have a solid impression of cold starts after that.
Cheers
Craig

2012 GRiSO (Factory rollered, Beetle mapped)
V7-II (deceased - shoved up a roo's arse at speed)

beetle

  • Guest
Re: The problem with single throttle body V7's
« Reply #13 on: January 29, 2017, 03:17:50 PM »
So the first table shows that there is no compensation of the a/f ratio once the engine temp (how is engine temp defined?) is over 60C. 

Not exactly. There are other correction tables, the MAP correction being the major one. The fuel-engine-temp table has a big influence, however. This means that at cruise, as the engine gets hotter the AFR will stay constant, even though it should be leaning out slightly as the temp rises.
The engine temp is measured directly by a sensor in the right cylinder.

Quote
Not sure what this has got to do with cold running issues?

Absolutely nothing. It's just another confounding thing about this map.


 
Quote
To me the table says that the mixture is enrichened at lower temperatures (good).  I guess that the enrichment is not enough to stop the cold stumble.


The TPS issue is the problem. They've used a kludge to get around it instead of addressing it.



Quote
Table 2.  Sorry, I need to know what the figures in the boxes are.  Vertical axis is RPM, Horizontal is TPS.
The error is perhaps that the figures peak mid rpm range at larger TPS values, rather than peaking at min rpm as at lower TPS values....which I suspect gives a rich mixture mid-range????


The values are injection pulse-width times in microseconds. The richer values midrange are due to poor VE at those breakpoints.

Have a look at the values at 4000 and above in the 45-65 TPS range. See how the same value is used on multiple cells? That's bad.


Ignore everything above 7250 for now. It's a recycled software. They just couldn't be arsed fixing that small thing.  :rolleyes:

 

Offline SED

  • Guzzi Hero
  • *****
  • *
  • *
  • *
  • *
  • Posts: 1551
Re: The problem with single throttle body V7's
« Reply #14 on: January 29, 2017, 04:17:24 PM »
Beetle,
This is fascinating stuff - I'm learning a ton.  Thank you. 

It's is all new to me so have a few questions if you have the time. 

"The TPS issue is the problem. They've used a kludge to get around it instead of addressing it."  The kluge is the extra fuel to get the engine to run smoothly when the TPS jumps from 2% to 10%?

"The richer values midrange are due to poor VE at those breakpoints."  VE?  Volumetric Efficiency?  Would this be due to cam timing or profile?

"Have a look at the values at 4000 and above in the 45-65 TPS range. See how the same value is used on multiple cells? That's bad."
Is that because the same value 6113 would be rich at 6500 rpm and lean at 7250 rpm?

Thanks,
Shawn
1983 LeMans III
1981 Monza
1947 Ariel Red Hunter
1939 Ariel Red Hunter
1937 Guzzi GTV

beetle

  • Guest
Re: The problem with single throttle body V7's
« Reply #15 on: January 29, 2017, 04:58:52 PM »
"The TPS issue is the problem. They've used a kludge to get around it instead of addressing it."  The kluge is the extra fuel to get the engine to run smoothly when the TPS jumps from 2% to 10%?

Correct.


Quote
"The richer values midrange are due to poor VE at those breakpoints."  VE?  Volumetric Efficiency?  Would this be due to cam timing or profile?


Primarily the valve size and cam timing/profile, but port shape and size air/exhaust speed affect VE.


Quote
"Have a look at the values at 4000 and above in the 45-65 TPS range. See how the same value is used on multiple cells? That's bad."
Is that because the same value 6113 would be rich at 6500 rpm and lean at 7250 rpm?


Yes!



Offline kingoffleece

  • SplitWeight(tm) seat covers
  • Guzzi Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 3494
  • Rated 5 STARS Motorcycle Consumer News
    • King of Fleece LLC SplitWeight(tm) seat covers
  • Location: Western New York
Re: The problem with single throttle body V7's
« Reply #16 on: January 29, 2017, 08:21:59 PM »
Not trying to be a wise guy.  I just let my bike warm up for a few moments and ride.  What am I missing?
SplitWeight(tm) seat covers. A King of Fleece LLC product.

beetle

  • Guest
Re: The problem with single throttle body V7's
« Reply #17 on: January 29, 2017, 09:12:24 PM »
You're not missing anything. When I suggest that the response isn't always positive. :laugh:

Now, if you can convince every one of those impatient owners to wait 2 minutes, problem solved.  :thumb:

Offline stevet

  • Guzzi Hero
  • *****
  • Posts: 2112
  • What would Mr. Happy Puppet do?
Re: The problem with single throttle body V7's
« Reply #18 on: January 29, 2017, 11:14:59 PM »
You're not missing anything. When I suggest that the response isn't always positive. :laugh:

Now, if you can convince every one of those impatient owners to wait 2 minutes, problem solved.  :thumb:

Patience... 10 years and 60,000 miles of cold starts on Suzuki and Yamaha motorcycle engines not needing 2 minutes of warm up time is my problem.  And cold for me means as low as the upper 20F range.

Really, warm up time isn't a problem.  Warm up time on a computer controlled, fuel injected engine a decade and a half into the twenty-first-freakin'-century is the problem.  My first car was a late 70's fuel injected Audi.  Robert Bosch injection permitted me to turn the key and go.  I'm spoiled.  Having to wait for a modern motorcycle to warm up a couple minutes can be tiresome.  I'll be awaiting the results of your fellows from down under.

Steve.
Steve T.
Twin Cities, MN
Sophia, '16 Moto Guzzi V7 II Stone
Feejer, '10 Yamaha FJR
"Il Viaggiatore", The Traveler. A.K.A. Via. 2017 FIAT 124 Spider Classica

"What we do during our working hours determines what we have; what we do during our leisure hours determines what we are."
-George Eastman.

beetle

  • Guest
Re: The problem with single throttle body V7's
« Reply #19 on: January 30, 2017, 03:02:20 AM »
You're 100% correct, Steve. You should be able to start & ride.

pete roper

  • Guest
Re: The problem with single throttle body V7's
« Reply #20 on: January 30, 2017, 03:11:40 AM »
That's the thing that pisses me off. Sure you can start the bike and give it a couple of minutes BUT YOU SHOULDN'T HAVE TO! It's 2017 for heavens sakes! Would you put up with that from your car? Or your washing machine? GAKK!

ponti_33609

  • Guest
Re: The problem with single throttle body V7's
« Reply #21 on: January 30, 2017, 05:28:43 AM »
I have posted this in another thread but since switching to Beetle's map my bike as been smooth as silk.  Start and go.  No hesitation, no gas smell, just runs great.  My bike is also quieter/smoother without removing the nice rumble from my exhaust.  That is important to me especially living in a community building with other condo owners.  Thx again Beetle for your efforts.

Offline Kev m

  • Not your normal Hombre
  • Guzzi Hero
  • *****
  • Posts: 29583
  • Yo from Medford, NJ
Re: The problem with single throttle body V7's
« Reply #22 on: January 30, 2017, 06:51:17 AM »
Yup it's the principal.

Well that and a gravel driveway and short EU side stand that makes me not want to run it unless I'm sitting on it. And if I'm sitting on it I get impatient to go.
Current Fleet

18 Guzzi V7III Carbon Dark
16 HD FLHP
13 Guzzi V7 Stone
11 Duc M696

Offline kingoffleece

  • SplitWeight(tm) seat covers
  • Guzzi Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 3494
  • Rated 5 STARS Motorcycle Consumer News
    • King of Fleece LLC SplitWeight(tm) seat covers
  • Location: Western New York
Re: The problem with single throttle body V7's
« Reply #23 on: January 30, 2017, 10:04:44 AM »
Got it.
thank you.
SplitWeight(tm) seat covers. A King of Fleece LLC product.

Offline rboe

  • Guzzi Hero
  • *****
  • Posts: 5091
Re: The problem with single throttle body V7's
« Reply #24 on: January 30, 2017, 11:49:24 AM »
It will be interesting to see if they fixed it with the V7III.
Phoenix, AZ
2000 Quota 1100 ES Black (sold & gone)
2008 Honda XR650L
2012 Griso SE
2013 Honda CB1100

Offline sib

  • Guzzi Hero
  • *****
  • Posts: 1712
  • Location: Smallest state, 221 times smaller than Texas, often compared to the size of an oil slick, forest fire, or ice sheet
Re: The problem with single throttle body V7's
« Reply #25 on: January 30, 2017, 12:24:19 PM »
Yup it's the principal.
Well, actually, it's the principle, unless you're referring to either your mortgage loan or Mrs. Jones at PS 201. :cheesy:
Current: 2021 V7 Stone E5
Previous: 2016 V7II Stone
Previous: 2013 V7 Stone
Several decades ago: 1962? Honda CB77 Super Hawk

Offline dguzzi

  • Guzzi Hero
  • *****
  • *
  • Posts: 1424
  • I'd rather have a tractor beam than a winch.
Re: The problem with single throttle body V7's
« Reply #26 on: January 30, 2017, 01:51:41 PM »
Thanks you guys for taking the time to investigate this stuff AND take the time to explain it to the rest of us!
'03 EVT
'87 Cagiva
'72 Commando
'71 Commando
'04 Troybilt
'00 Tundra
'90 Miata
'16 Mustang

Offline neverquit

  • Sunday Rider
  • **
  • Posts: 193
Re: The problem with single throttle body V7's
« Reply #27 on: January 30, 2017, 02:15:06 PM »
First, thanks Beetle for the post.  I'll be following this thread and your progress with the maps, I may want one for an older single throttle body model.  Regarding the VE comments, I think the whole purpose of the new engine head design in the V7III is to improve the VE in order to maintain performance while meeting the new Euro regulations.  The map for the new engine should be interesting.

Offline Kev m

  • Not your normal Hombre
  • Guzzi Hero
  • *****
  • Posts: 29583
  • Yo from Medford, NJ
Re: The problem with single throttle body V7's
« Reply #28 on: January 30, 2017, 02:37:14 PM »
Well, actually, it's the principle, unless you're referring to either your mortgage loan or Mrs. Jones at PS 201. :cheesy:
Auto correct is my enema! [emoji23]
Current Fleet

18 Guzzi V7III Carbon Dark
16 HD FLHP
13 Guzzi V7 Stone
11 Duc M696

Offline Andy1

  • Sunday Rider
  • **
  • Posts: 166
  • Location: UK
Re: The problem with single throttle body V7's
« Reply #29 on: January 30, 2017, 04:30:04 PM »
Beetle - Thanks for the explanation of what the table means.
You say there are other correction tables - what are those?  Just trying to understand the beast
Cheers
Andy1

 

20 Ounce Stainless Steel Double Insulated Tumbler with donation credit
Buy a quality tumbler and support the forum at the same time!
Better than a YETI! BPA and Lead free.
Advertise Here