V11 Misfire

[mfeeney]

I'm a newbie to the Moto Guzzi culture and need some diagnostic help. A 2004 V11 with 8000 mi has an misfire between 2-3000 rpm under light throttle. No other symptoms or issues. This is an intermitant situation. I've replaced the spark plugs and inspected the high voltage wires with no clues. It is equipped with the M-G titanium pipes and the newly mapped ECU that goes with them.

 

mfeeney

[Alex-Corsa]

I'm a newbie to the Moto Guzzi culture and need some diagnostic help. A 2004 V11 with 8000 mi has an misfire between 2-3000 rpm under light throttle. No other symptoms or issues. This is an intermitant situation. I've replaced the spark plugs and inspected the high voltage wires with no clues. It is equipped with the M-G titanium pipes and the newly mapped ECU that goes with them.

 

mfeeney

 

If you mean some kind of cough at 2400-2600 , I have noticed it on mine (sport 1100i) as well.

Have changed the fuell map on the chip and went better, that means it no longer happens always, but when the engine and weather is a bit warmer (i.e. oil temp.above 83 or so) and above 20C air it happens form time to time. Can't do anything about it but I don't worry it isn't so often anyways.

[docc]

That's pretty low rpm to expect the V11 to bebuttery smooth, yet a solid throttle body balance with TPS setting including a world spec valve adjustment may work magic.

 

Thanks to Jeff in Ohio's tune up procedure it's all laid out for you. Give it a try!

[Ouiji Veck]

Throttle body balance is my guess too.

[droydx]

TB and tune are important starting points. Also: Make sure you don't have any exhaust leaks at any of the junction points, fron x-over, head pipe to rear x-over or even at the x-over to exhaust cans. A slight air leak can make for a lean/rich condition at certain RPMS...pop. You can sometimes see some soot, or even feel the exhaust pulsing out if you have a leak. Finding the leaks is easy, curing them is tougher.

 

 

Andy

[Guest Mattress]

Very good advice so far....start with a proper tune!

 

Also, I cast suspicion on Moto Guzzi's temp sensor in the head. Doesn't seem like a good design. Some folks have replaced theirs with a good brass holder. I just mention that because I wonder is some folks problems aren't related to a mis-reading temp sensor.

 

My MG runs super so I don't want to mess with it, but someday I probably will replace the plastic p.o.s. holder with the brass one if I have driveability issues.

[Guest sethicus]

I'm a newbie to the Moto Guzzi culture and need some diagnostic help. A 2004 V11 with 8000 mi has an misfire between 2-3000 rpm under light throttle. No other symptoms or issues. This is an intermitant situation. I've replaced the spark plugs and inspected the high voltage wires with no clues. It is equipped with the M-G titanium pipes and the newly mapped ECU that goes with them.

 

mfeeney

Sadly, my 2000 V11 had a similar stumble that confounded a few mechanics until one of them discovered a worn bushing on the right side throttle body that was leaking air and creating a lean condition under a variety of driving situations(idle, 4000rpm cruise,etc). A mechanic has been machining me a new one at a huge cost savings(1600 smackers for new throttle bodies!). the buzshing is found under the return spring for the throtlle body butterfly. It is what seals the shaft that goes into the throttle body. best of luck seth.