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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 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.
The dash measures...
Guzzi Diag I assume reads the Voltage from the ECU via a different route or does it also read it from the dash?
The only true way to read the battery Voltage is with a Voltmeter at the battery terminals, anything else is just an approximation.
You say the Voltage is measured via "one of the several ADC ports", Do you know which one (pin no?) or is it 17 alsoI assume 17 supplies the ECU loads(supply for discrete outputs is it also an ADC?
..., tracing the wiring it has a Predisposition Condenser and a Predisposition Diode listed. I don't know what i'm to make of those two items, it almost looks like something tried in the past to capture the peak battery Voltage.
Am I right in thinking the capacitor doesn't exist and the diode is jumpered out? That would surely make a big difference to the Voltage reading? 0.6 higher than with the diode. Removing the diode would require a different injector time offset would it not?
The diode even a Shottky must have some effect on the Voltage reading due to it's forward bias for example if the battery is at 12.5V the ECU will see 12.5 - 150 to 450mV. While adding the diode would not change the injector timing directly it would change the Voltage the ECU reads and therefore it will change the digital readout on the dash compared to a digital meter applied directly to the battery it must also change the Map in some way.
A 47µF capacitor is quite significant, it probably takes the ECU Voltage input a few seconds to discharge that under cranking so it will make the ECU think the battery is a little higher than reality, does it just have to fool the logic? I'm sure that the factory could have fixed the starting much better by making a change in ECU logic rather than trying to fudge it. On other models they added a Startup Maintenance Relay to override the ECU controlled Start Relay.
Have you ever seen a document describing the ECU logic? It bugs me that I can make changes in the controls of a chemical plant but I'm not able to understand how my simple motorcycle is programmed.
Hi Roy,your reasoning is sound and I don't disagree. The fact of the matter is that I've never measured the effect of the diode included in the Guzzi fix on injection times. I did measure the significant effect of changing the voltage calibration factor on injection time, however. Apart from measuring, it is also directly noticed when riding the bike. I've not heard of such effects as a result of a diode installed.Well, the capacitor buffers the voltage during starter engagement and avoids the low voltage error. Basically a different approach than changing the wiring to avoid the startus interruptus. And yes, changing the respective parts in the code would have achieved the same result. Your guess why this wasn't done is as good as mine.No, I haven't seen any document from Marelli or Guzzi describing the ECU logic. However, a small team consisting of John Th. from the UK, Beard and myself, have been reverse engineering the 5AM, focused on the 2230, code beginning 2 years ago. The result is a good, if not yet complete, understanding of the code. The library approach used in the code also served well to reverse engineer the BINs used in Ducatis and other makers. I've posted the findings on this (https://wildguzzi.com/forum/index.php?topic=93758.90) and other boards and invited anybody interested in participating in the enterprise to join. Nobody did....CheersMeinolf
So it's just a simple way of boosting the voltage in cold weather when the battery volts drop too much.Not dissimilar to the Ultracapacitors used in some cars with stop start technology.The diode is there to stop current flowing back towards the battery.