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Engine exceeding rev limit


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Hi Cameron.

That is clearly going over the limit, but is because the DC is at 100%.  It turns out you are kind of correct but not quite.  Fuel limiting will not operate at 100% DC, but nor should 100% DC EVER be reached by your injectors.

You have the master fuel number set to 17ms and the highest load in your fuel table only sees early 50's in their DC.  You are loosing a lot of resolution this way, and would suggest you use a lower master fuel number and higher DC numbers in the fuel table.

Max loads would be better at 80-90% DC leaving some room for trims to add in fuel etc.  The reason you show 100+% DC, is really showing you have injectors that are too small for the job.  Either get bigger injectors, or raise the fuel pressure may suffice.


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  • 9 years later...

a friend of mine is running  a plugin bmw m50 G4 (fw 4.10.2), and has also experienced the loss of rev limiter once switching to e85 and injector DC over 100%.

He uses currently fuel cut, so that seems to be in line with what I've read on here.

does the ignition cut will be effective above 100% dc?

There is no workaround on g4 for the fuel cut above 100% dc right?


Thank you

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Yes, ignition cut will work correctly. 

Even if you change to ignition cut it would still be strongly recommended to fix your fuel flow issue.  Most injectors will be locked fully open by about 90% DC so wont flow any further fuel above above that.  Your already beyond that quite a bit so it is very dangerous, there is no reserve if for instance you get a small boost spike or something that requires more fuel.

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