Any ideas?
I'm trying to get the fuel flow to virtually drop to zero when the vehicle decelerates.
No matter what I adjust seems to have any effect on the fuel usage on deceleration.
Regards,
Neil.
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Any ideas?
I'm trying to get the fuel flow to virtually drop to zero when the vehicle decelerates.
No matter what I adjust seems to have any effect on the fuel usage on deceleration.
Regards,
Neil.
Have you played with the DFCO settings? It will cut fuel on decel when its conditions are met.
Cheers,
I've tried modifying the DFCO, Throttle Cracker and other areas but they only drop the fuel consumption to about 4.5ltrs/100kms then it starts to increase to about 12ltrs/100kms before the vehicle completely stops. The fuel consumption then drops away to about 2ltrs/100klms at idle.
You can also cause surging to occur if you go too far.
After releasing the throttle the vehicle goes into cruise control slowly dropping in speed.
There should be away of instantly reverting to the idle state after releasing the throttle.
Does anyone have any examples of the required table changes that will achieve this result?
Thanks,
Neil.
The injectors will never TOTALLY shut off. The pulse width that will be commanded when in DFCO is the value in the Injector Voltage Offset table. If reading thi you have the temptation to change this value to 0 DON'T!!!
I assume you are monitoring the fuel consumption on the LCD display in your particular vehicle. I'm not sure how accurate that will be in this case. I can assure you the the minimum pulse without DFCO active would e in the region of around 1.7ms which will flow a lot more fule than the 0.52ms of pulse in DFCO!
Give up on this one and move on to the next tuning item on your list ;)
I think you might be able to tweak dfco more. Change the map points too. Mine hangs onto cutoff until almost idle then opens out again with a bit of a jerk but thats cool.
You can change the ramp rates to make it cut off faster too. There are quite a few dfco settings to play with.
You can drop your enable speed as well as raise the enable map point (depending on how your car is)
Look down under spark for more dfco settings and obviously kill the 2 sec enable delay.
do you have a manual or auto? Auto's don't really activate DFCO that often when decelarating in 4th as there usually isn't an converter lock up so all the parameters aren't met to activate it. Try locking it in 3rd or 2nd and try if it is an auto. Mine usually indicates 0.4 on the instant fuel when DFCO is active.
I've got an auto but I don't think DFCO must be working properly.
It seems to want to go into cruise and slow down very slowly.
Regards,
Neil.
Get your car up to 70-80 kmph, manually pull it into second gear and let go of the throttle. Does it engage then?
(Adjust to a lower speed if you are running 4.11's or you will over rev!!!)
Cheers,
post up your tune so maybe we can help you out.
I suspect my LT1 (1994 5.7L Gen II Small Block) DOES completely shut down the injectors under decel when DFCO comes in. When monitoring the O2 sensor voltages both drop to 0.004v fixed nearly immediately when the DFCO engages. You can then feel the deceleration kick in. As soon as the DFCO disengages, the O2's returned to normal operation (fluxuation).
I have heard people talk about agressive DFCO being a very bad thing, like piston breakage. Can someone elaborate on why?
My settings are not the same as EFILive has, but might shed some light on a good DFCO setting (note this is very close to factory GM settings).
This is NOT a terribly agressive DFCO, but it works pretty well. I can make it run a little harder, but I don't feel the need, I did try it and returned back to these settings and perfer them over being more agressive.
Quote:
Originally Posted by Tordne