Author Topic: GuzziDiag Voltage reading - Norge question  (Read 211 times)

Online PJPR01

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GuzziDiag Voltage reading - Norge question
« on: September 13, 2019, 11:53:00 PM »
So...I'm going thru my annual GuzziDiag checkup on the Norge, doing the Throttle body balance, and checking a few parameters.

GuzziDiag tells me my voltage is 12.8 or 12.9 at idle, barely moves at 3k rpm from that setting, occasionally blips up to 13.0, but doesn't stay there.

I decide to check the voltage using another source by plugging in a high quality device into my cigarette lighter socket near the battery, and it also reads 12.8/12.9 at idle.

I pull out my test meter and attach it to positive/negative terminals and it reads 13.2 to 13.3 while the bike is running.

So which one am I to believe now?  Anyone else seen this discrepancy with GuzziDiag *(version V0.47), or do other folks see the same reading on their Norges?

Thanks!
« Last Edit: September 13, 2019, 11:55:14 PM by PJPR01 »
Paul R
2015 Red/Black Griso
2008 Silver Norge
2002 V11 Scura

Online Kev m

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Re: GuzziDiag Voltage reading - Norge question
« Reply #1 on: September 14, 2019, 07:01:41 AM »
I used to see a similar voltage drop between the battery terminals and the dash readout on my B11.
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Online Chuck in Indiana

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Re: GuzziDiag Voltage reading - Norge question
« Reply #2 on: September 14, 2019, 07:40:44 AM »
Isn't that voltage low, no matter how it's tested? I would think around 14V would be "normal" at cruising rpm.
Chuck in (Elwood) Indiana/sometimes SoCal

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Offline beard

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Re: GuzziDiag Voltage reading - Norge question
« Reply #3 on: September 14, 2019, 10:46:29 AM »
As already written:

The ECU measures the voltage not at the battery poles.
There is at least one fuse and several contacts between.

This results in a lower voltage which is seen by the ECU.

There is a correction factor available, but ... don't try to adjust it.
Since there are many values which depends on the voltage, like injection and ignition.
Less voltage means more time is needed for the coils and the injectors.
If you adjust the voltage value to be more real, the engine runs verybad, until you also correct the voltage dependend tables.
To much todo for only getting the 'real' voltage.

But that's alos a reason why a Guzzi is not starting, even if you measure 12.0V at the battery.
The ECU measures 11.5 V and don't allow to start.

Online Kiwi_Roy

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Re: GuzziDiag Voltage reading - Norge question
« Reply #4 on: September 14, 2019, 10:57:52 AM »
Use your multimeter to measure the battery Voltage, you can connect directly to the battery with that.

Guzidiag is telling you the Voltage at the ECU, i'm guessing after the Kill Switch.
« Last Edit: September 14, 2019, 11:06:47 AM by Kiwi_Roy »
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Online Chuck in Indiana

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Re: GuzziDiag Voltage reading - Norge question
« Reply #5 on: September 14, 2019, 11:44:33 AM »
Use your multimeter to measure the battery Voltage, you can connect directly to the battery with that.

Guzidiag is telling you the Voltage at the ECU, i'm guessing after the Kill Switch.

I thought that was what he was saying..
Quote
I pull out my test meter and attach it to positive/negative terminals and it reads 13.2 to 13.3 while the bike is running.
Chuck in (Elwood) Indiana/sometimes SoCal

02 Scura RC
87 AeroLario
79 G5
95 Skorpion tour
 
The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt.' - Bertrand Russell

Online pete roper

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Re: GuzziDiag Voltage reading - Norge question
« Reply #6 on: September 14, 2019, 06:58:46 PM »
My G8 has never shown more than 13.4 on the dash. Always measures just under 14 at the battery. Never fails to start, if I haven't ridden for a week or more in winter the dash may drop out before it fires but it always fires up. Never suffered from Startus Interuptus either.

Stelvio on the other hand always reads 14.2, never drops the dash out, always has 14.2 at the battery, also always starts!

(Shrug?)

Having read Beard's explanation I am going to immediately cease giving it any more thought, not that I was exactly straining my brain over it before this! :grin:

Pete

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Re: GuzziDiag Voltage reading - Norge question
« Reply #7 on: September 14, 2019, 07:34:00 PM »
Your battery is old and tired
I can only do what I can do - CS

Online pete roper

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Re: GuzziDiag Voltage reading - Norge question
« Reply #8 on: September 14, 2019, 07:41:44 PM »
Mine? Ummm? No.

Online Kiwi_Roy

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Re: GuzziDiag Voltage reading - Norge question
« Reply #9 on: September 14, 2019, 11:56:39 PM »
Pete
 I presume by G8 you mean Griso 8 Valve
If it's wired this way it will eventually suffer
Perhaps the factory wired the bikes for OZ better.
http://www.thisoldtractor.com/guzzi007/schematics/2008_Griso_8V.gif
The Start relay is powered from a switched fuse
The fix is to cut the yellow wire feeding start relay and wire it from a direct supply
The Earlier 2 Valves were wired direct but then they used a tiny wire from relay to solenoid this one has a second Startup Maintenance Relay, a waste of space IMHO

Out of curiosity watch the number plate light while someone else starts the bike
« Last Edit: September 15, 2019, 12:03:02 AM by Kiwi_Roy »
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Online PJPR01

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Re: GuzziDiag Voltage reading - Norge question
« Reply #10 on: September 15, 2019, 09:51:40 AM »
Thanks everyone...will check a few scenarios now including the battery...perhaps it is fatigued, charging it again today to see if it's holding voltage or dropping. 

However, assuming the battery does check out to be fine, how to tell whether itís the alternator,  alternator belt or voltage regulator that is the potential culprit for the low voltage output.

Presumably, change the belt, test it again and see if there has been any improvement would tell me but is there another way to know?

Thanks all!

Just for fun, I'm going to run the same tests on the Scura and Griso and see what sort of readings I get there.
« Last Edit: September 15, 2019, 09:57:27 PM by PJPR01 »
Paul R
2015 Red/Black Griso
2008 Silver Norge
2002 V11 Scura

 

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