DTA S40 soft fuel cut-off on overrun

This section is dedicated to discussion of DTA engine control units such as the DTA E48 EXP, P8 Pro, DTA S40, S60, S80, and S100, as well as all things ECU related.
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rjwooll
Posts: 81
Joined: Wed Jan 28, 2015 5:42 am
ECU Model: S40 Pro
Distributor: Lotusbits
Firmware Version: 75

DTA S40 soft fuel cut-off on overrun

Post by rjwooll »

I'm looking for a way to achieve a soft fuel cut-off on overrun (and soft cut-in when throttle reapplied.) The reason is that the car is a little jerky around town at low speeds - it is a Lotus Elite automatic. I was hoping to use throttle transients, but they are dependent upon pedal position/speed. Is there another way of achieving this?

Thanks, Richard
Rob Stevens
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ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: DTA S40 soft fuel cut-off on overrun

Post by Rob Stevens »

Not that I can think of.
Sounds more like its not mapped very well.
Try massively reducing ignition in the areas you are having trouble, so long as you have no sudden steps this might smooth it out.
Alex DTA
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ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: DTA S40 soft fuel cut-off on overrun

Post by Alex DTA »

The only option is the overrun parameters, but these are simple on/off values.
stevieturbo
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Re: DTA S40 soft fuel cut-off on overrun

Post by stevieturbo »

No doubt it will be a lot smoother with throttle overrun cut off, turned off. ie there will be no fuel cut.
rjwooll
Posts: 81
Joined: Wed Jan 28, 2015 5:42 am
ECU Model: S40 Pro
Distributor: Lotusbits
Firmware Version: 75

Re: DTA S40 soft fuel cut-off on overrun

Post by rjwooll »

Just returned to the forum after a long absence!

Thanks for your comments. Yes, there is no problem if fuel cut-off isn't configured, but I'm probably an exception on this forum as I don't race, but aim to have a highly efficient road car. This means great performance when I want it, but conversely no fuel wastage when I don't. I reckon fuel consumption has improved by 5-10% since I configured the fuel cut-off option. All modern cars come configured with a soft fuel cut-off so I just wondered if such an option existed with DTA. I now understand it doesn't - and as it's only a minor problem doesn't worry me.
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: DTA S40 soft fuel cut-off on overrun

Post by stevieturbo »

I would be utterly amazed if fuel consumption has improved by that amount, purely from an overrun fuel cut.

In fact more than amazed, unless you spend a huge amount of time going down steep hills miles long.

You could achieve a lesser cut by scaling map columns and at overrun load cells above a certain rpm, you could reduce fuel injected.....although that would be fairly normal anyway.
Rob Stevens
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Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: DTA S40 soft fuel cut-off on overrun

Post by Rob Stevens »

Indeed, to save loads of fuel on the overrun by invoking the cut fuel function the fuel must be pouring in in the first place!
rjwooll
Posts: 81
Joined: Wed Jan 28, 2015 5:42 am
ECU Model: S40 Pro
Distributor: Lotusbits
Firmware Version: 75

Re: DTA S40 soft fuel cut-off on overrun

Post by rjwooll »

Strange but true! Admittedly I did have to push it back up the hill to get those results...
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