=jon= Posted January 23, 2017 Share Posted January 23, 2017 Hi All On very light throttle, such as tickling it along at 60mph on a dual carriageway with a slight downhill slope, the throttle will be very jerky - it's like the MS thinks it should be cutting fuel, then when you press the accelerator slightly more it comes off overrun fuel cut with a jolt and lots of transmission shunt. I've tried recalibrating the throttle sensor but that's made no difference. Any suggestions? Thanks Jon Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 23, 2017 Share Posted January 23, 2017 What percentage overrun fuel are you running? Auto or manual? Do you have your AE tuned nicely? Quote Link to comment Share on other sites More sharing options...
=jon= Posted January 23, 2017 Author Share Posted January 23, 2017 It's an auto. Here's the fuel cut settings: AE is reasonably well tuned - no stutters etc when accelerating / mashing the throttle. Looking at the above, maybe it's just as simple as changing the TPS Lower than % to something a bit lower! Durrr.. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 23, 2017 Share Posted January 23, 2017 What code version are you on? MS1/2/3 and version? 029v or...? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 23, 2017 Share Posted January 23, 2017 Ah, I see, I think MS1 029v... Firstly I would turn that off, and go for a drive, see what difference it makes, if it helps, then great, we can look elsewhere Second, that setting is a bit of a big hammer blow to the engine, there is a better way.... so turn that off, then go into 'Accel Enrichment Wizard', look at the 'Decel fuel amount (%)', report back... I have previously run autos with 0% in there, however... they ran like you describe, and actually are much better/smoother when set to about 80% when coming back on the throttle, not sure why, but you can't cut it that much in there Quote Link to comment Share on other sites More sharing options...
=jon= Posted January 23, 2017 Author Share Posted January 23, 2017 According to Tunerstudio, MS2 Extra release 3.3.3 (I'm not online in the landy right now!) Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 23, 2017 Share Posted January 23, 2017 Doh, screens are similar, but called 'Decel fuel amount' in MS2. Quote Link to comment Share on other sites More sharing options...
=jon= Posted January 23, 2017 Author Share Posted January 23, 2017 Decel Fuel Amount is currently 90% When it wams up a bit I'll go outside and have a play Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 23, 2017 Share Posted January 23, 2017 Cool, 90% is default Turn the other one off and fingers crossed then Quote Link to comment Share on other sites More sharing options...
=jon= Posted January 23, 2017 Author Share Posted January 23, 2017 Thanks for your help Quote Link to comment Share on other sites More sharing options...
HoSS Posted January 27, 2017 Share Posted January 27, 2017 Its a while since i've played with this... CLT should be just below warm temp e.g. 85 I think the TPS 5% could be a bit high, i would make it 1% 0.5s for delay And i would put a 1s delay for EGO on fuel return But first as Bowie says, turn it off and see what it does to eliminate that as the cause. Quote Link to comment Share on other sites More sharing options...
need4speed Posted January 28, 2017 Share Posted January 28, 2017 Jon did that help switching it off? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 28, 2017 Share Posted January 28, 2017 When I researched it, with an autobox, if you run full fuel cut you will get bucking, and I experienced this during experimentation. The best I could get away with was 80% for a smooth drive. Quote Link to comment Share on other sites More sharing options...
=jon= Posted January 28, 2017 Author Share Posted January 28, 2017 I've not had a chance to take the laptop out yet and change it - it's on my list of jobs (along with fixing the cold start fuelling so it starts easily when it's sub zero)... As it spends 95% of it's time running on gas, it's only when it runs out and I have to switch back to petrol that it reminds me to sort the petrol fuelling out... Quote Link to comment Share on other sites More sharing options...
=jon= Posted February 27, 2017 Author Share Posted February 27, 2017 Tested this over the weekend, the jerky on/off throttle transitions have gone With regards to the cold start fuelling - I added a load to the Cranking Pulse values and now it starts nicely on petrol from cold - however the values seem high compared to what tunerstudio suggests is 'normal' : 10c = 500%, 20c = 400%. Is this usual, just a quirk of the v8? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 28, 2017 Share Posted February 28, 2017 So what did you change to smooth out the throttle response? Before/after values would be informative for future generations Quote Link to comment Share on other sites More sharing options...
=jon= Posted February 28, 2017 Author Share Posted February 28, 2017 Before : Overrun Fuel Cut = on After : Overrun Fuel Cut = off Quote Link to comment Share on other sites More sharing options...
need4speed Posted February 28, 2017 Share Posted February 28, 2017 Glad you got sorted Jon Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 28, 2017 Share Posted February 28, 2017 Yup, result, I doubt the fuel savings would have been much Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 1, 2017 Share Posted March 1, 2017 A low bottom row of the fuel table will do a very similar job but can be blended in more subtly. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 1, 2017 Share Posted March 1, 2017 Indeed, and the overrun fuel % on one of the screens does similar, 80 is about the limit though Quote Link to comment Share on other sites More sharing options...
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