150mV TPS re-hash

[scra99tch]

There seems to be a consensus that this first step is not needed.  Is it because any variation from 150mV to 525mV on the ECU can be made up with the air bleed screws?

Take for instance your at 175mV when you back off the plate stop screw on the L/H side.  So you go ahead and screw the screw in until you encounter 525mV +/- 25mv.  Your angle plate is now smaller than what factory tech manuals suggest. You then achieve idle/balance of 1100 RPM with R/H plate screw.  Does it really even matter as the adjustments your making are just so small in throttle plate angle that you would not notice the difference.  Or is there a method to the madness because the range from 150mV to 525mV corresponds to the proper starting angle of the plates.  Which would translate into off idle throttle performance. 

I thought I would raise this question because I never wondered why some individuals have their air bleeds open 2 turns and I was able to get away with only 1/8 turns of the air bleeds.  Barring any other air leaks, C/O trim, or casting differences. 

 

[Kiwi_Roy]

Setting the TPS at 150 makes sure there is no chance of hitting the end stop for the pot.
I sometimes skip the next step and just use the fast idle lever to set idle.

If you think of the map as a large spreadsheet with mV as the vertical axis the TPS selects the row to use.

[scra99tch]

If you don't have 3.6 degrees maybe 3.4 what does it read for that column on the fuel map?

[Wayne Orwig]

If you are at idle, and at 3.6 degrees (or 540mv or whatever it is on your model) indicated on the TPS, then you are not going to hit the ends stop of the TPS. That has nothing to do with setting an initial 150mv.
Setting the initial closed 150MV, then cranking it up, sets the initial 3.6 (or whatever) degrees. So the throttles are close to the perfect idle position at that point.
My info from Moto Guzzi years back, shows setting the air bleeds to a set value, depending in the model, at that point. And if a Tonti model with the sloppy dual linkages, set the idle balance with the idle stops screws. Set the TPS again. Then set the high speed balance screw.
At that point, since you have the idle opening set, on the next tune up, why back out the idle screw and repeat all of that. You don't see late model bikes backing out the idle stop at every tune up. You aren't even 'allowed' to. Just set the idle balance, high speed balance, TPS. And go ride.

[FGO]

I am probably just lazy, 10 years ago, I installed an old PCIII, tuned the bikes, set the valves, set the tps at 150, and had it dynolinked tuned by Louie in Acton, Ca. He knew guzzi tuning very well.  that was 25,000 miles ago, I have not touched anything in the past 10 years and it is still the best running guzzi I have. It only has 25K since the last tune, I ride other bikes, but man, it has been nice not to need to mess with anything.  I would have to say it runs exactly like it did 10 years ago, (same spark plugs too)  I have other bikes that are a bit more needy, but not my 02 Cal SS.  I found the same thing with my 02 Lemans when I had Louie do the same thing to it.  Never touched it again

[Kiwi_Roy]

If you are at idle, and at 3.6 degrees (or 540mv or whatever it is on your model) indicated on the TPS, then you are not going to hit the ends stop of the TPS. That has nothing to do with setting an initial 150mv.
Setting the initial closed 150MV, then cranking it up, sets the initial 3.6 (or whatever) degrees. So the throttles are close to the perfect idle position at that point.

Not to argue but back 10 years ago without Guzzidiag how would you set 3.6°?
With the throttle plate fully closed, that's a fixed point easy to convey, anyone can find it.
So how to convey to the masses how to zero the TPS, I know, shoot for some value of mV, why 150 my guess is that makes sure when the throttle is wide open it doesn't bang up against the other end also it doesn't skip the bottom rows on the fuel map.

Then you crank the butterfly stop to get 540 mV, that's just a first attempt at an idle position.

[rodekyll]

But Roy -- When you set the tps to that value, it's a 2-step dance: 

You have the throttle stop screw on the tps side backed out past zero, so when the throttle plate closes it's completely closed. 

Then turn the tps body to your desired setting.

Tweak the throttle stop to where the multimeter (or diag software) first twitches in response to turning the screw.  This contact point is the true zero point of the throttle plate -- and more tweaking of the screw and the tps value changes.  Any less and it doesn't.  This is the only point of throttle plate rest that the tps can be accurately adjusted to.

Check the meter again.  Tweak tps body (never again the tps side stop screw) as needed to make the value you want.  Check as you tighten down the tps that the value doesn't change.

forget it from there on unless you suspect someone has messed with the screw or you suspect an actual tps problem.  I check mine because it's on the diag readout.  10 years on one and it has never changed.  7 years on the other and ditto.

[bmc5733946]

We never got a Guzzi out of the crate that was set-up correctly from the factory during the time when the TPS was adjustable by turning, not one.  That 150Mv is critical for a base line, however the ones that ran well, I learned over time to leave alone.  Some others have good results simply adjusting the TPS for best running at idle.  If I was starting from an unknown spot I'd try the 150Mv but I wouldn't consider it an absolute.

Brian

[Kiwi_Roy]

David,
         When I first got into adjusting the TPS, (high mileage VII Sport) I soon realized there was no such thing as a sacred zero stop screw, if you adjust just the left screw it will never idle at the same speed twice because of the slop in the linkage.
I set both side zero stops so they just grip a slip of paper, from there I wind them both in by the same amount, that way the throttle plate is at the same angle on both sides and the idle speed is consistent between blips of the throttle, I find when I do a balance I hardly have to touch the air bleeds
 
The EV is completely different from a VII Sport because the linkages are quite different.

As far as I know the fuel map is made up of 15 rows (TPS Voltage) x 16 Columns (Engine Speed)
So the mV between breakpoints would be about 300 mV, at idle speed between 300 and 600 it's on the second row.

Once you have the idle set, that's the new mV set-point, I think that's what you are referring to on the diag readout

Besides Gentlemen I don't think we have answered the original posters question properly.

Do we need to set 150 mV
Could it be set at WOT

[rodekyll]

I won't argue that, other than to suggest that setting the voltage to a random throttle stop position doesn't get the zero baseline set.  Otherwise, I'd blame the carbon can. 

[Kiwi_Roy]

Someone, I think it might have been Wayne told me he sets it at WOT I don't remember what Voltage must have been 4.5 or 4.75

[rodekyll]

I read that, although I don't remember if it was Wayne.  I've never used that method for setting tps (I have set timing that way), so I can't comment on it.  Last week at someone's house we watched the tps sweep on a dual TB setup (bassa) and noted the 3.2 angle (relates to 150mv) gives the correct 'full open' value.  So it seems reasonable that the correct full open value would return a reasonable idle opening.  I'll try it at my next opportunity.

[Wayne Orwig]

Not to argue but back 10 years ago without Guzzidiag how would you set 3.6�?
With the throttle plate fully closed, that's a fixed point easy to convey, anyone can find it.
So how to convey to the masses how to zero the TPS, I know, shoot for some value of mV, why 150 my guess is that makes sure when the throttle is wide open it doesn't bang up against the other end also it doesn't skip the bottom rows on the fuel map.

Then you crank the butterfly stop to get 540 mV, that's just a first attempt at an idle position.

In 1998 I was using MSDTS or whatever the original Techno Research program was called. But you could just as easily set the voltage to represent 3.6 or 2.1 or whatever degrees. 150mv equals zero degrees. Roughly 354mv equals 3.6 degrees. I have a chart for that somewhere.
 
Before the software, they actually had you close the butterfly to zero, and turn the TPS until it just rested against the butterfly. Or zero degrees opened, and zero degrees of TPS movement. Then opened it for the right idle speed and balance. You can still do that, but it is difficult.

You want it right because the fueling near idle is very hard to hit right. Nothing to do with banging against anything. And the butterfly is physically at 3.6 degrees, so 3.6 degrees it is.

The main thing is to have the butterfly opened to 3.6 degrees (or whatever your bike takes) and the TPS to match that 3.6 degrees.

[scra99tch]

OMG,

How do I know Throttle is at 3.6 unless I use the base of 150mv with throttle plate screw just touching?  Then turn that in until I read 3.6 or 525-540mV. 

From what I gather rodekyll is doing L/H plate screw out, loosen TPS to desired setting of 150mV, tighten down TPS.  Screw in screw until mV changes, now loosen TPS and go for 3.6 540 mV?? Tighten recheck.  I always thought you readjusted the plate screw not the TPS to get your Desired mV.

This makes a big difference I would think.

Guzziology has my head swimming even more, but I get the idea. 



This is what I have been doing, Jackal and Calvin.

Engine warm/off

Air bleeds closed
Throttle plate screws backed out
TPS 150mV
L/H plate screw until 3.6 or corresponding mV
Engine on
R/H plate screw until balanced
Air bleeds open 1-1.5 turns
Try to Achieve 1150 rpm (May need idle trim adj ??)
3500k balance L/H linkage bolt adjuster.

Done. 


From what I gather now

Air bleeds closed
L/H plate screw out
Turn TPS 150mv hand tighten.
L/H screw in until slight mV change
Loosen TPS and shoot for 540mV, tighten re-check
Engine on
Now R/H screw until balanced on carb sticks
Open air bleeds to 1-1.5 turns
Achieve 1150 rpm
Balance at 3.5k with L/H linkage screw.


Are the plates supposed to be "closed" at 3.6?

[Wayne Orwig]

I'm not sure why you are balancing using the RH plate screw

The air bleeds balance at idle
The white knob for open throttle

Sounds like you are confusing Tonti frame and Spine frame throttle bodies. They ARE different.

[Kiwi_Roy]

Sounds like you are confusing Tonti frame and Spine frame throttle bodies. They ARE different.

Sorry, I was jumping back and forth between here and VII Lemans, I shouldn't try to multi-task (took my last post off)
Are we talking EV here

[rodekyll]

Sorry, I was jumping back and forth between here and VII Lemans, I shouldn't try to multi-task (took my last post off)
Are we talking EV here

Me too -- I'm talking duals.

[Meinolf]

Hi,

the ECU contains a 8bit A/D which converts analog to digital. The resolution is 5V/256 = 0.01953V.




The ECU starts registering the TPS opening beginning at 0.156V = 0�. If another value is used as base setting then a corresponding shift occurs across the board. Which is most noticeable in the lower TPS areas.

Cheers
Meinolf

[rodekyll]

Is this why I've been told a different base setting affects the fuel mixture for the entire range?

[scra99tch]

From what I gather now

Air bleeds closed
L/H plate screw out
Turn TPS 150mv hand tighten.
L/H screw in until slight mV change
Loosen TPS and shoot for 540mV, tighten re-check
Engine on
Now R/H screw until balanced on carb sticks *Edit Only R/H screw until slight MV change back off?
Open air bleeds to 1-1.5 turns
Achieve 1150 rpm and balance
Balance at 3.5k with L/H linkage screw.


Anyone confirm that this is what is actually needed, becuase I have no idea where I went south with my ideas, no offence to people from the south.

[Wayne Orwig]

the ECU contains a 8bit A/D which converts analog to digital. The resolution is 5V/256 = 0.1953V.

I assume you meant 0.01953V, or 19.53mv.

[Wayne Orwig]

Air bleeds closed
L/H plate screw out

What bike are you talking about now?

The info I have from Moto Guzzi says to set the air bleeds 1/2 turn open on the 15M. 1 turn open on the P8 and 16M. And it notes for the Quota "CLOSED forever".

[Wayne Orwig]

L/H plate screw out
Turn TPS 150mv hand tighten.
L/H screw in until slight mV change
Loosen TPS and shoot for 540mV, tighten re-check

That can't work.

[scra99tch]

So reading a PDF from Guzzitech the user states.

Back off plates screws.
Set TPS to 150mv
R/H plate screw for 540mV
L/H plate screw looking for slight change in MV back off a smidge
Engine on
Balance idle for 1150 RPM


Bike is 1.5M Calvin

I only turn the TPS buy hand for the 150mV, then which plate screw for 540mV, or does it matter?

Sorry but I've got so many approaches to this in my head I am thoroughly confused, but yet slightly intrigued because I "know" what needs to happen.

[Wayne Orwig]

So reading a PDF from Guzzitech the user states.

Back off plates screws.
Set TPS to 150mv
R/H plate screw for 540mV
L/H plate screw looking for slight change in MV back off a smidge
Engine on
Balance idle for 1150 RPM

From what I know:
R/H plate screw for 540mv.
Well 540mv is 3.6 degrees. 3.6 degrees applies to the P8 only. The P8 generally is older Californias and EVs (and not to forget Daytonas). Those Tontis have the TPS on the L/H plate. Not the R/H plate.

[Kiwi_Roy]

Hi,

the ECU contains a 8bit A/D which converts analog to digital. The resolution is 5V/256 = 0.1953V.




The ECU starts registering the TPS opening beginning at 0.156V = 0�. If another value is used as base setting then a corresponding shift occurs across the board. Which is most noticeable in the lower TPS areas.

Cheers
Meinolf

Just as I thought there's about 300 mV between each row
The ECU starts registering at 156 mV but why that value, why not zero or 50mV, because if you used zero the pot would be touching the end stop at the same time as the throttle plate touched, which one is holding it?
Using a value above zero ensures that it never touches
Given this information when the bike is set up for idle around 500 mV it never gets to use the values in the bottom row.

[scra99tch]

I believe 1.5M is also 3.6 or 525mV +/- 25mV.

Alright now I am getting it slowly.  Somewhere along the line I got mixed up this should help tremendously.

Thanks

[Meinolf]

Hi,

I assume you meant 0.01953V, or 19.53mv.

yes, my mistake.

Cheers
Meinolf

[Meinolf]

Hi,

Is this why I've been told a different base setting affects the fuel mixture for the entire range?

yes. And all others scalars and tables which use the TPS value.

The ECU sees the actual value +/- deviation from the TPS base setting.

Cheers
Meinolf

[Wayne Orwig]

Bike is 1.5M Calvin

I only turn the TPS buy hand for the 150mV, then which plate screw for 540mV, or does it matter?

Sorry but I've got so many approaches to this in my head I am thoroughly confused, but yet slightly intrigued because I "know" what needs to happen.

The CalVin 15M does use 3.6 degrees (unlike the older P8, which was 2.1 degrees, or about 384mv).

A full blown setup would be, air screws 1/2 turn, unhook left T/ linkage. back out left idle stop. set TPS=150mv. Turn in idle stop for 540mv (you should now be at a physical 3.6 degrees plate opening for good idle). Reconnect linkage. Balance idle with idle stops. Tweak TPS=540mv if needed. Balance high speed w/ screw on linkage.
That was the setup instructions Guzzi provided years back. They did NOT want you to tweak the air screws for idle balance. But you can and I sometimes do. I believe their thinking is that if you open the air screws too much, you may close the butterflies too much to make up for it.

If I get in a machine that is running OK. I do NOT do the 150mv part. Waste of time IMHO since you already have close to the proper amount of air going in so the throttle plate is close to the required 3.6 degrees already. Why screw it up. (you don't see people on a Norge/Breva/Griso/etc backing off the idle screw. In fact it is forbidden.) I usually just set air screws to 1/2 turn. Then idle speed/balance with idle screws. Then 540mv TPS tweak. Then fast speed balance on the linkage. And go ride.