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EFI idle

24K views 20 replies 12 participants last post by  Axe56 
#1 ·
Why do harley efi's have to idle at around 1100 rpm's ?
What would happen if you dropped it to around 7-800...
 
#3 ·
Why not? My old 76 FLH idled so slow you would swear it would die, no oil pressure problems. Is this something specific with the Twin Cam? I know it is not with the Evolution and I though the Twin Cam got the good oil pump. I tried to set my idle lower on my vrod and it did not like to run. One thing I did not like about my 05 FXSTI was the high idle. Just doesn't sound as good.
 
#5 ·
It is not an oil pressure related issue whatsoever!!!

Its a charging issue - the fuel injection system and ECM require a good strong supply of 12.8V min. Long periods of low idle can cause battery voltage to drop below this, and not supply the necessary power to the system. Hence the higher idle to ensure constant and consistent higher voltage from the charging system.
 
#15 ·
I dropped my RPM's on my 99' Glide classic down to 800 a while back, didnt like dropping into first and "clunking" so hard. So far so good, I agree, long periods of idle would not be good for the system. Good thing I dont spend too much time showing off, and plenty of time ridin' !!
 
#18 ·
Google it. Or....wait till morning and ask Schmidty. He's good with the MM EFI bikes.
 
#20 ·
To properly setup the Magneti-Marelli EFI a Scanalyzer or Digital Technician and breakout box is needed . I've seen the systems so badly misadjusted that it took a couple hours to get them corrected . On some occasions it's not even the throttle body that's out of adjustment , one or more sensors out of parameters can affect the system .
The Delphi EFI systems have to be adjusted with a Scanalyzer or Digital Tech. . The idles are set electronically . 950 RPMs minimum and (I think ) 1150 max . Also only adjustable when the engine has reached operating temp. .
 
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