Fuel adding when coasting

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Fuel adding when coasting

Unread postby RIKIL » Tue Mar 28, 2017 6:47 pm

When I coast downhill I can feel a little bit of fuel being added into the motor so I get a slight surging. It isn't enough to increase the speed too much but it is definitely noticeable. Only happens when I coast though, never uphill but always downhill. Any idea what function is that would cause this?
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Re: Fuel adding when coasting

Unread postby jsa » Tue Mar 28, 2017 10:17 pm

Decel fuel shut off
Cheers
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Re: Fuel adding when coasting

Unread postby decipha » Wed Mar 29, 2017 2:15 am

dfso kills the injectors so it should show a false lean on the wideband being maxed out

if its going richer it would take quite a bit to cause any surging .8 lambda or less
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Re: Fuel adding when coasting

Unread postby RIKIL » Wed Mar 29, 2017 9:29 am

Thanks guys, I found decel fuel shut off by MPH and RPM that I will look at changing. Both are set pretty low now (700RPM and 25MPH).
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Re: Fuel adding when coasting

Unread postby decipha » Thu Mar 30, 2017 12:39 pm

The dfso min rpm is added to DSDRPM

so if your idle rpm is 800 then +700 = 1500 is the minimum rpm to allow dfso

I usually set the dfso rpm to 1300 so dfso won't be able to function below 2100 rpm or so
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Re: Fuel adding when coasting

Unread postby RIKIL » Thu Mar 30, 2017 1:23 pm

Good to know.

I had good luck changing decel MPH from 25 to 35. That got most of it out and I am going to put the RPM to about 1700, I think that will be good for me.
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Re: Fuel adding when coasting

Unread postby decipha » Thu Mar 30, 2017 4:13 pm

yea I use 35mph as my minimum as well except on big ol luxury sedans where it becomes bothersome
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91 4r70w - Skarlett
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