Start issue :-(((

Starting issue on my 06 Breva 1100.
The bike was put in the garage for two months, battery removed
(A couple of days before I got some rain)
Two months later pushed the start button: "clanck" but no crank. Shit... I thought I wouldn't go through this again when installed an MPH-like cable kit two years ago...

I spent a whole day together with a friend, an automotive electrician, trying to figure out...
- battery used is brand new and poles are clean
- earth point over the start motor cleaned
- ecu sockets cleaned
- fuses are fine
- engine off, I get 12,8V on battery poles, on dashboard 11,8V.
- engine on, 13,8V on poles, never got more than 13,6V on dashboard

We found out that connecting the start button to the start relay, thus bypassing the ECU, the engine starts perfectly.
Seems like the ECU sees something it doesn't like...
Any clues of what can be the cause?
How indicative is the dashboard reading?

And last, what will happen if I just leave it like that (ecu bypass)?

Whenever that happened to my GRiSO, fixed it by cleaning the conector at the solenoid.

I believe most - if not all - wires are undersized. Thats why even with the suspision that something get loose or dirty, strange things happen. There is a voltadge drop at the wire from the battery to the dashboard, so the reading is lower. There is a voltage drop at the wire from the generator to the battery, so even if your battery is fully charged by a charger, the voltage on the bike does no exceed 14V and the battery can not be kept fully charged by the bike. There is a voltage drop at the wire that feeds the fuel pump/ignition coils/injectors so if any connection gets loose/dirty the ECU can show a variety of false failures.

And there is a voltage drop at the wire from the relay to the solenoid, so the solenoid does not engage.

For the no start issue, my opinion is that the best solution is as folows:
(note its for GRiSO, for Breva the wires may have other colours)

[You must be registered and logged in to see this link.]

okuraner wrote:

Voila! It worked. As Pete wrote, I cleaned all terminals, sockets, earth strap but unfortunately it did not start. Then, through searchin internet, by chance I found "Allegato M-605" which is Moto Guzzi Technical Training February 2010. This 59 pages file is real life saver. On page 52, there is a section with head line "Problem solving course Sheet No:20 Starting Failure Applicability : All models.
I copied and paste the solution : "CAUSE: Insufficient cross section of the +12V wire energising the starter relay.
SOLUTION:
a) Identify the starter relay (orange/yellow, yellow, brown/pink and red/black cables)
b) Remove the relay and detach the Faston connector from orange/yellow cable, pushing
the tab down with a pin.
c) Prepare the additional length of cable (cross section 2.5mm2, as long as necessary)
d) Fit the Faston connector with the tab on the relay connector instead of the orange/yellow
cable.
e) Insulate the Faston connector from the previously disconnected orange/yellow cable.
f) Disconnect the Faston connector from the starter motor and fasten to the wiring harness
with a clamp to prevent it from dropping onto the silencer.
g) Connect the Faston on the additional cable in place of the old Faston connector.
h) Fasten the additional cable with the same clamp used to secure the starter cables"

It really worked. Now I wonder what are electrical engineers in Moto Guzzi doing all day long. Why don't they produce problem free motoryles.

Πέτρος :-)

Thank you Petros.
I already did that two years ago. I thought I was done with the starting issues. Apparently not...

Is the ECU taking into account the dashboard voltage reading or is it independent from that?

With a new battery, I was reading 14.1 volts on dashboard . Now, after 4 years, does not exceed 13.8.