V7 Mk2 down hill stalling issue.

[Off @ 90]

Hi, Just over one year ago my V7   Stornello developed an off throttle stalling problem after a  slow off road ride.
This went away mysteriously after a long road ride above 4000 rpm and all was normal again for rest of the year.
In December I go for another off road ride . This was 4wd track slow going with a steep down hill decent using engine braking all the way down . Well  the down hill stalling issue returned engine cut out when using engine braking otherwise runs normally getting home no problem just the odd stall coming to a stop annoying .
Checked air box for oil no problem there .I hooked up the cables to ECU no fault codes of consequence showing and Beetle map installed .
I then did a throttle self learn and parameters auto learn with Guzzidiag. Went for some long road rides to test and happy to say stalling problem has gone completely all normal. Cannot explain why this issue occurs but the self learn seems to have done the trick.The Stornello maybe more vulnerable to this issue as it appears to happen when off road and slow going  just above idle for extended periods.

[Dirk_S]

What’s “extended periods of time” to you?

[guzzisteve]

Let Beetle know, he may be able to adjust the map a bit.

[lucian]

My guess is that duration of off throttle engine breaking downhill pulled more air into the combustion process than fuel from the idle part of the fuel map could provide . At some point you must blip the throttle and throw some fuel into the equation.

[Off @ 90]

What’s “extended periods of time” to you?

The off road ride was approx 45min to 1 hour . The down hill section was very steep braking and first gear work throttle closed all the way for 20 min .

[moto-uno]

  I'd be more inclined to think that it was a somewhat rich mixture around the idle map leading to this . I too have
a Beetle map ( on a 2018 Eldorado ) and it seems a hint richer at those throttle settings , way preferable to the
stock ultra leanness though . I too am sure he could offer a modified map to eliminate this .  Peter

[Vagrant]

Does it have ABS? If so the system might be getting confused.

[Off @ 90]

  I'd be more inclined to think that it was a somewhat rich mixture around the idle map leading to this . I too have
a Beetle map ( on a 2018 Eldorado ) and it seems a hint richer at those throttle settings , way preferable to the
stock ultra leanness though . I too am sure he could offer a modified map to eliminate this .  Peter

The stalling occurred before and after I installed  Beetle's map . A 796 map was installed originally . Stalling problem re occurred one year later the common  theme was slow engine running / braking. The TC was off and ABS has no affect on engine . I think the ECU gets confused with prolonged steep down hill engine braking as you can have over 3000 rpm with throttle closed 1st gear  . I am very happy with Beetle map big improvement over 796 map. Most of my riding is sealed road and the odd bit of gravel. Probably will not do any more 4wd goat tracks so stalling problem will not re occur I  am thinking .

[80CX100]

"My guess is that duration of off throttle engine breaking downhill pulled more air into the combustion process than fuel from the idle part of the fuel map could provide . At some point you must blip the throttle and throw some fuel into the equation."

The stalling occurred before and after I installed  Beetle's map .,,,

I think the ECU gets confused with prolonged steep down hill engine braking as you can have over 3000 rpm with throttle closed 1st gear  .

     I think Lucian above has id'd what's going on.

     On an old carb fueled bike even with the throttle shut, with engine braking and that much vacumn it'll still be pulling some gas through and keeping the engine running.

     On your EFI bike, if your engine is turning 3k rpm on a long downhill stretch, that's a lot of air going through the engine, but if the throttle is kept shut, the injectors won't be squirting fuel in no matter how much the vacumn tries to pull it in.

     If your bike doesn't have linked brakes, try dragging the back brake, and when the trail isn't real gnarly give it a little bit of gas.

     I'm not that familiar with EFI in general, but possibly you could richen up your trim or base idle setting, idk?

     Good luck

     Kelly

     

[Tom]

Too low of an rpm in gear.
Too high of a gear going downhill.
Too lean of a fuel mixture to be going downhill.

Any and all in combination will give you what you're getting.