how to set decel fuel cut?
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racepak
- Posts: 64
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- Location: israel
how to set decel fuel cut?
hello everyone. can anybody help me with decel fuel cuts. i cant seem to set it proparly and the car poops everytime i decel. i searched alot and i didnt find any specific order on how to set the decel, thanks.
I'm actually going to try a write-up later when the weather agrees with my car. It rained for 2 straight days, now its snowing. 
The 2 main culprits you'll be adjusting: the [scalar] value for the 1st vac column and the value for min mbar in the fuel cut window. This is how you get the initial values for the two: Vac column: Datalog your MAP signal - go WOT to a higher RPM, then 0% down to 1500rpm or so. Look at the datalog graph and note your lowest MAP reading during decel. I like to change the 1st vac column value to a 10-20mbar lower than the datalog value. Min Mbar activation: I add about 20-50mbar to that lowest datalog value. I've tried a few values in my beater and it doesn't get that bucking unless you're very slow in a high gear (under 2k). I drove to work with a TPS% of 5% then 1% the next day, and I didn't see a difference. At this point, it drops rpm's fast until about 2k, which is the min rpm for fuel cut. From what I've read, the problem is when the decel vacuum is lower than your lowest vac column, it wraps to the highest boost column. The time lookup value (default is 600msec) checks it that often, and apparently squirts the fuel equal to that boost column for a fraction of a second.
The 2 main culprits you'll be adjusting: the [scalar] value for the 1st vac column and the value for min mbar in the fuel cut window. This is how you get the initial values for the two: Vac column: Datalog your MAP signal - go WOT to a higher RPM, then 0% down to 1500rpm or so. Look at the datalog graph and note your lowest MAP reading during decel. I like to change the 1st vac column value to a 10-20mbar lower than the datalog value. Min Mbar activation: I add about 20-50mbar to that lowest datalog value. I've tried a few values in my beater and it doesn't get that bucking unless you're very slow in a high gear (under 2k). I drove to work with a TPS% of 5% then 1% the next day, and I didn't see a difference. At this point, it drops rpm's fast until about 2k, which is the min rpm for fuel cut. From what I've read, the problem is when the decel vacuum is lower than your lowest vac column, it wraps to the highest boost column. The time lookup value (default is 600msec) checks it that often, and apparently squirts the fuel equal to that boost column for a fraction of a second.-
greasemonkee
- Posts: 150
- Joined: Wed Oct 03, 2007 2:35 am
- Location: Hooterville, NC
There's really more to it than that. Not sure why or if it was intended, but there seems to be a transitioning period after fuel resume (when winding down) were fuel isn't cut, but it hasn't resumed to full fueling resulting in a lean condition. I've tried to get rid of it in many ways, but there seems to be no remedy and no way around it other than turning the fuel cut off.
Thats exactly what I do. The biggest problem I had when first adjusting it, was short little spikes to a higher mbar value (like hitting 230 shortly while have 220 set) that was causing it to kick on and off. I usually just do 1% tps and datalog as you have described above.HiProfile wrote:I'm actually going to try a write-up later when the weather agrees with my car. It rained for 2 straight days, now its snowing.
thats gr8. but what should i do until you finish? i tryed hiprofile's mathod but it didnt work. i also played with the values for about 2 hours in my work's parking lot. and still no sucsess, mabey i did somthing wrong? mabey in the whole calibration of the map? im asking this because i'm kinda frustrated i didnt had all these issues with the silver thing. i have lots of issues with basic settings (jumping idle tip in and tip out) besides that the car runs good,calvin wrote:i'm modding the routine to function better. i'm working now as today with thomas on it on the dyno
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JaredKaragen
- Posts: 1504
- Joined: Fri Nov 23, 2007 4:00 am
- Location: Bay Area, Ca
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well, i played with settings for hours. here you can see all my trouble: seems like what ever i do, it still cuts fuel under 198mbarJaredKaragen wrote:its very tough to get column 1 dialed in.. it's a "hipshot" at best until you get to drive/log some higher vacuum conditions. most of your tipout richness as described above will come from col 2 from my experiences.
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ive tried everything as well. tip out is at -95%, fuel cut has been set at many places and i've tried disabling fcut and tuning but that isnt working per calvin. we will just have for calvin to get it done. He's got his hands busy right now tho.
eCtune Authorized Tuner Blake Barr Pensacola, FL XXX Performance - In House DynoJet 850-457-DYNO
Well thats just not right. its a basic setting, it should have been taken care of from the get go, if thats ectune i'm not gonna keep driving like this for a much time, driving with this function jeopardizes my engine and i am not going to keep using ectune without any changes taken with this function. i remember asking calvin about fuel cuts wayyyy before i purchased the software and he didnt mentiond any bugs.98vtec wrote:ive tried everything as well. tip out is at -95%, fuel cut has been set at many places and i've tried disabling fcut and tuning but that isnt working per calvin. we will just have for calvin to get it done. He's got his hands busy right now tho.