Originally Posted by
JeepsAndGuns
Well did some more tweaking today and had some good results, so I figured I would just go ahead and keep adding to this thread.
I touched on this a little bit when I got my vss working and dfco started working. When it would come out of dfco, it would jolt the engine when it cut the fuel back on. Basicly it would be like you just lightly bliped the throttle. At first it wasnt annoying, but it kept on untill it did! After a little while it became VERY annoying. Would do it at about 1500 rpm, and I had not gotten to the point when I downshit. (remember, I am running a manual trans)
Well I find this parameter in scalers under "AE parameters" called "post DFCO AE pulse" with the discription that it provides a AE pulse when exiting dfco if no tps increase. I thought that kinda odd. Why would it want to add more fuel when kicking the fuel back on if the throttle did not get re opened. I did drop it straight to zero right away, I took it in steps. The jolt got lighter the lower I went untill i eventually set it to zero. Now it simply cut the fuel back on post dfco, but didnt add any extra AE. The jolt was a lot less that it was, but there was still a jolt (like you bliped the throttle) when it turned the fuel back on.
Now just to keep from confusion, there is still a parameter for a AE pule when exiting dfco if you DO open the throttle. I forgot exactly where it is. But that one makes sense. Your in dfco slowing down and then need to accel again (like slowing down for another car making a turn, then you take off again) I left that setting stock, as it does just fine if I hit the gas again when in dfco.
Now back to the jolt when it kicks the fuel back on. I thought about it and where it kicks it back on at 1500 rpm, it would be nicer if it did it at a lower rpm. I did a little more carefull looking at all the avalable parameters in my xdf, and found something I thought would be usefull. Its under tables and is under dfco parameters and is labeled " minimum dfco rpm vs. temp. In a nutshell its basicly what I was looking for! Its what rpm it cuts the fuel back on post dfco, and it splits it up into diffrent tepatures. I changed it to 1000 rpm for most closed loop temps, and a little highr for colder temps. Saved it, burnt a chip and took it for a drive. Sucess! I now no longer have the jolt when in dfco, because now it doesnt cut the fuel back on while I am still slowing down! It now does the jolt/blip when I push in the clutch to downshift. I watched the rpms and it doesnt drop lower than it should, the fuel cutting back on catches it, and it still does that blip. I now like it, because its like your bliping the throttle in between downshifts. I actually can kinda time it just right and use that blip when double clutching and not even have to touch the throttle. Kinda a added bonus...lol
BUT not all was well. Because I lowered the min rpm, I now made it to where if I was at parking lot/driveway speeds, it will go into dfco! Say like you pull out, drive a few yards while still in first gear and let off again, it went into dfco real quick and then the jolt of cutting the fuel back on, made a interesting combanation, and not a good one. It was like hitting the brakes and the gas real quick.
So some more digging around in the xdf, I find the parameters in scalers under "dfco parameters" and found the two parameters "minimum MPH to enter dfco" and "MPH to disable dfco"
The first one was set to 10 mph. I doubled it to 20 mph. I figured there was no need to go into dfco under 20. I then changed the disable dfco from 7 mph to 15 mph. That way, I have to be going 20 mph or faster for dfco to come on, and under 15mph, dfco is completely disabled.
Saved, burnt a chip and test drive. I now have full sucess! I now have no more jolt when slowing down, have a nice blip in the throttle between downshifts I can use when double clutching (that was completely unexpected, and just kinda a added bonus side effect), and no more dfco at too slow of a speed.
Hopefully all these little updates may help another manual trans 7427 user one day.
Bookmarks