Moto Guzzi V11 Sport FBB

[callison]

Hah! Made you look! Actually, FBB stands for "Fuse Blowing Bastard". Hopefully, I may someday find out what blows the ECU fuse when I whack the throttle open. As it stands right now, I've tried Dave Laings spare ECU in place of mine in case the ECU is the problem. Apparently not, the fuse still blows with either ECU. I installed auxiliary grounds on the ECU case and the regulator case. Fuse still blows. Swapped the regulator for the known good on the Sport 1100i. Fuse still blows. This leaves the wiring harness to swap out and the TPS. The weird part is - the bike runs really well - until the throttle is whacked open. Too weird.

[Guest davidb]

Got a spare tps laying around you could swap out?

[Paul Minnaert]

voltage on ecu doesn't come over 13 volts?

ignition coils?

[jrt]

My first guess would be the TPS- have you checked it's resistance at WFO? The other part involved would be the injectors, but I can't imagine how that might create a overvoltage or grounding fault...

[callison]

My first guess would be the TPS- have you checked it's resistance at WFO?  The other part involved would be the injectors, but I can't imagine how that might create a overvoltage or grounding fault...

52590[/snapback]

 

The fuse blows when I whack the throttle open but it doesn't need to be WFO to blow the fuse. I don't have a data logging DVM to take a peak voltage reading, but putting in a known good regulator should make a difference if the current regulator is bad. The different regulator makes no difference though. Whacking the throttle open with the bike on a stand does not blow the fuse, so I suspect that somewhere, there is a wire that moves under acceleration and shorts out. If Murphy is in loop as usual, that would be the coils, since they're in the most densely populated area of the frame and most difficult to deal with. Having said that, the culprit will probably be something REALLY weird like a bogus tachometer that puts an occasional high load on the ECU tach drive signal and makes the ECU crowbar. That shouldn't be possible of course, but I did say "really weird". That's a feeble attempt at humor folks, don't go speculating about tachs causing ECU problems unless you want to start a thread that's humor related because I don't think that such a thing is technically possible.

 

I will check the TPS though. Again. And order a new one.

 

BTW, I have changed the position of the ECU to either side up, plug orientation, jiggled and re-positioned all of the ECU wiring without affecting this fuse blowing problem.

 

Maybe I should just sell it and buy a Breva 1100...

[jrt]

Good that you have a datalogging DVM, but is the response time fast enough? You'll have what- a few 10s of milliseconds to register a voltage spike? Can you bridge the fuse and measure current (doubtful....)? That sure would be more useful if you could.

Anyway, can you attach some flying leads to the coils and probe there? If you think it's the coils, then that's the reasonable place to probe. Also, which fuse is blowing (see below) and can you probe the fuse itself? I'm not sure what that would tell you....

Also...since you're thinking about wacky alternatives, have you bypassed the clutch/sidestand safety switches and if so, that's a place to look. As is the electric petcock lead. And here's another wacky possibility-the wiring under the relay or the fuse block may be shorting out or it may be the injector relay itself, since that is fed by the ECU relay. Have a spare relay?

Man, there's just not a whole lot hooked up to the ECU fuse (good thing, I guess).

 

If you decide to replace the TPS, I've read that a harley part fits the California, so presumably the Sport as well (I think it was on Guzzitech?)

 

OK, looking more closely at your diagram labelled 4 March 2004. Is the fuse block labelled correctly? I think you have F1 and F2 reversed. F1 (5A) feeds the coils/fuel pump/injectors and F2 feeds the ECU. You have them listed as F1 ECU and F2 coils...

[callison]

Good that you have a datalogging DVM, but is the response time fast enough?  You'll have what- a few 10s of milliseconds to register a voltage spike?  Can you bridge the fuse and measure current (doubtful....)?  That sure would be more useful if you could. 

Anyway, can you attach some flying leads to the coils and probe there?  If you think it's the coils, then that's the reasonable place to probe.  Also, which fuse is blowing (see below) and can you probe the fuse itself?  I'm not sure what that would tell you....

Also...since you're thinking about wacky alternatives, have you bypassed the clutch/sidestand safety switches and if so, that's a place to look.  As is the electric petcock lead.  And here's another wacky possibility-the wiring under the relay or the fuse block may be shorting out or it may be the injector relay itself, since that is fed by the ECU relay. Have a spare relay? 

Man, there's just not a whole lot hooked up to the ECU fuse (good thing, I guess).

 

If you decide to replace the TPS, I've read that a harley part fits the California, so presumably the Sport as well (I think it was on Guzzitech?)

 

OK, looking more closely at your diagram labelled 4 March 2004.  Is the fuse block labelled correctly?  I think you have F1 and F2 reversed.  F1 (5A) feeds the coils/fuel pump/injectors and F2 feeds the ECU.  You have them listed as F1 ECU and F2 coils...

52609[/snapback]

 

I rely heavily for feedback on those schematics to spot that which I've missed (or just plain f*&^(d up). I'll check that out.

 

I DON'T have a peak reading DVM. Wished I did. Or a handheld oscilloscope. It's gotta be a wire. Somewhere. All of the other stuff mentioned is simply not on that fuse.

[dlaing]

OK, looking more closely at your diagram labelled 4 March 2004.  Is the fuse block labelled correctly?  I think you have F1 and F2 reversed.  F1 (5A) feeds the coils/fuel pump/injectors and F2 feeds the ECU.  You have them listed as F1 ECU and F2 coils...

I think Carl updated that a while ago, see the August 2004 diagram.

http://home.pacbell.net/guzzi007/schematic...9_V11_sport.gif

But maybe that is a clue! And for whatever reason Carl has the 5 Amp fuse protecting the fuel pump, etc.

[callison]

I think Carl updated that a while ago, see the August 2004 diagram.

http://home.pacbell.net/guzzi007/schematic...9_V11_sport.gif

But maybe that is a clue! And for whatever reason Carl has the 5 Amp fuse protecting the fuel pump, etc.

52645[/snapback]

 

Had maybe, not has. The 21 August 2004 schematic shows F2 as 10 amps. That matches the various manuals I've located (all over) my disk drive. I really do rely on the sharp eyes of you guys out there to keep me honest. I'm really good at making mistakes...

 

Snatching defeat from the Jaws of Victory, our hero attempts to leap the curb in a single bound, but instead, falls flat on his face.

[jrt]

Aw, Carl- you're doing a great service to the community. We really do appreciate it and I guarantee that if I were to make these schematics, they'd be A LOT worse. In crayon probably, and I'd only use one color.

[dlaing]

Aw, Carl- you're doing a great service to the community.  We really do appreciate it and I guarantee that if I were to make these schematics, they'd be A LOT worse.  In crayon probably, and I'd only use one color.

52678[/snapback]

A Great Service indeed!

Reading Carl's schematic makes life so much easier.

And his website is Awesome!

Carl is a true Guzzi Hero!

[Skeeve]

Snatching defeat from the Jaws of Victory, our hero attempts to leap the curb in a single bound, but instead, falls flat on his face.

52647[/snapback]

 

But the judges give him a 5.8, 5.9, & a 4.5* for an aggregate of 5.4 out of 6.0 on his dive to the pavement. Not bad!

 

 

 

Ride on,

 

 

* - [one o' those darn Soviet judges who hasn't figured out the Cold War is over yet!.. ]

[tikkanen]

Hi Carl,

 

My Scura has blown fuses in the last couple of days but it's the ignition that's playing tricks with me.

Luckily I have a handful of 15 amps fuses in my tool pouch but it's a pain in the arse to be the laugh of the day at work when I have to change fuses as everybody else is driving home.

 

Has anybody else experienced this or is it just me who has to live with this? The problem didn't occur when I rode the standard setup. Could it be the PC III?

 

Thanks in advance

 

Søren

[callison]

Hi Carl,

 

My Scura has blown fuses in the last couple of days but it's the ignition that's playing tricks with me.

Luckily I have a handful of 15 amps fuses in my tool pouch but it's a pain in the arse to be the laugh of the day at work when I have to change fuses as everybody else is driving home.

 

Has anybody else experienced this or is it just me who has to live with this? The problem didn't occur when I rode the standard setup. Could it be the PC III?

 

Thanks in advance

 

Søren

52695[/snapback]

 

Which fuse specifically?

 

The next time you go for a ride, please do me a favor and pop up Helsingor and eat one of the hotdogs they sell at the entrance, then tell me how wonderful it was. Little pieces of onion ring on them and all of that. I miss them terribly.

[callison]

I rode the Fuse Blowing Bastard to work today - it's my birthday dammit and I wanted to ride something with more panache than the California. Blew the ECU fuse twice. Once on a very narrow mountain road with loads of crazy California cage drivers blowing by at about 50 mph a foot away. Okay, so now I know my heart still works. Wished like hell I could figure what's causing the fuse to blow. New TPS on order.