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
The feel of engine breaking is the spark being withdrawn... Love the avatar :)
If you look at my tables, I don't change the spark on decel. The factory setting did, I leave it alone so it uses the Closed Throttle Spark table instead. I was having some anomoly that when it would go into DFCO, and the timing dropped, it would never come back up and my timing would be in the dumpster until I restarted. Puzzled me until I figured out it was DFCO triggering it. If I didn't allow DFCO, no issue. So DFCO Timing Retard is the amount of timing that is pulled out when DFCO is active. So whatever value in the Closed Throttle Spark table - DFCO Spark Retard = Total DFCO timing. So when I set DFCO Spark Retard to 0, then I leave my timing alone to the Closed Throttle Spark Table.
There is a significant difference in decel without the fuel vs with, and even factory you can feel the 45-48 mph point where fuel comes back on. I have tried and tried to get it significantly lower than 45 mph and although I can, the transition from fuel off to fuel on is too abrupt and my limited PCM wouldn't let me transition smoother.
Quote:
Originally Posted by Tordne
I havent touched my DFCO in my tune, so I decided to give mine a test today.
My car is VX Commodore LS1 Auto.
I can make the dash display 0L/100 if I go downhill and do a manual downshift to second at speed.
Cheers,
When DFCO comes in on pulse width typically drops to somewhere between .200 ms and .350 ms (depending on the vehicle) and O2 voltage goes to .004 mv. With the stock cals I've looked at, the transition to DFCO is very slow because of a slow rate of spark adjustment. DFCO won't become active until ignition timing hits the value in B3336. (The description is not correct. This isn't the value to which timing will be adjusted when DFCO is active-- it's the value that activates DFCO. Spark will drop until it reaches the value in B5915.
Make sure that the value in B5919 isn't higher than the values in B3336 or you'll never hit the timing enabler for DFCO. Try values between .06 and .09 in B3334 to achieve a ramp in rate you're happy with. Values in B3335 (Ramp Out Rate) will be in the .4 to .7 range. Don't forget to adjust the other enablers (rpm, MAP, speed and throttle). If all else fails, send me your tun file.
Sorry for the n00b question, but I haven't got EFILive yet. What do you mean by the values in B5919 or B3336? Is this something in the datalog/scanner that is a specific location?
Love the sig! 1+1=10..... And FWIW the systems I used to work on 7+1=10.....
I was begining to wonder if anybody got it. Sig used to be 7+1=10, then F+1=10. Figured it needed another change, so I went to the binary version. I used to work on octal systems as well. One of the best stories is the time we were installing an electronic cash register system in a department store and some electricians were on site. We were counting cable pairs coming into the system and you should have seen their faces when we counted 1,2,3,4,5,6,7,10, then went on to 16, 17, 20. They couldn't understand what happened to 8, 9, 18 and 19. Ever try to explain an octal or hex system to someone?
As for your EFILive questions, every table in the tuning software is numbered. B3334 is the DFCO Spark Ramp In Rate table, B3335 is the Ramp Out table. It's a little confusing at first, but all you have to do is enter the table number in the navigator window and hit search. The system will display he table for you. It might not be a bad idea to download the software from the EFILive web site and begin looking through it before you get your system.
N0DIH,Quote:
Originally Posted by N0DIH
No problem, feel free to ask questions all you like.
Download and install the software from here: http://www.efilive.com/download.aspx
Without a cable it still runs... you can view logs and view/edit tunes... you just can't log or flash;
real sample logs and tunes are included as are tutorial PDF's (see the Auto VE tutorial, for example).
Cheers
Joe
:cheers:
lol...Quote:
Originally Posted by dfe1
How about base 36 (...I think IBM did use base 36 a long time ago...)...
Base 36 uses the digits 0-9 and A-Z, so... Z + 1 = 10
:D
Looks like you still have enable delay there!
Hi dfe1,
I would appreciate if you could have a look at this tune and advise on the correct setting up of DFCO.
It doesn't seem to work no matter what I do.
I would really like for the engine to virtually cut all the fuel on deceleration.
It's just a standard non modified auto engine
Any help that you could offer would be greatly appreciated.
Thanks.
Regards,
Neil.
looking at your tune your map B3320 settings were to high.try this tune.
Try this. Some of the settings may not be what you're expecting-- don't change them. DFCO should become active as soon as you take your foot off the gas pedal. Let me know how it works.
Did you remove the attached file for a reason?Quote:
Originally Posted by dfe1
I wasn't aware it had been removed. I'll repost it as soon as I can find it.Quote:
Originally Posted by mistermike
Images reposted
Thanks.Quote:
Originally Posted by dfe1
I am looking to buy EFILive soon, but don't have any experience with it, what are these tables here, like B3336 and such? What are the values? How do I view them?
Download/install the software from www.efilive.com/downloads
Then from the tunetool, open a sample bin file (say 2001_Corvette_Man.tun or 2002_Camaro_Auto.tun for example)
located in the folder My Documents\EFILive\V7\bin.
Then in the tunetool's search dialog box (upper left, under "Navigator:"), type B3336 (uppercase B) and press Search...
this takes you directly to table B3336...
Each table shows:
- description of what the table does,
- links to related tables,
- each axis's units and max/min values.
Press F1 to bring up the tunetool user manual pdf for more info.
so these settings are working for ppl? I have been told (seen on here) from several that cutting DFCO off makes it worse...well from these tables several of the enablers are set to off..that doesn't entirely cut it off correct? just eliminates that enabler?Quote:
Originally Posted by dfe1
how many ppl have had succes stories from this? I'm interested in just stopping my car from going rich on decel...i don't want to try and CUT fuel, just get it away from going rich
I've used the data (or something very close) in the tables I posted in a variety of vehicles with excellent results. The values are fairly aggressive, so you may want to soften the spark ramping a bit. There won't be any doubt when DFCO becomes active-- wide band AFR readings will go to 19:1 and you'll feel a change in the rate of deceleration. If you're having problems, I'd be happy to look at your file and make some suggestions.
Why don't you want to cut fuel?
dfe1's settings work great on my GTO. There's an abrubt transition when fueling comes back on. I haven't played with ramp rates yet.
Must have something to do with the blower. In the vehicles I've done the transitions in and out are undetectable except for the change in the exhaust sound and increased engine braking during decel. You may need to alter the MAP settings to account for differences in manifold pressure transition time. It sounds like you have the air and spark back well before fuel is back to normal.Quote:
Originally Posted by mistermike
Also-- an item of interest. In my LL8 (Trailblazer 6 cyl), I noticed that pulse width during DFCO is reported at .000 ms. Obviously, that's not correct, but it apparently has something to do with the P10 ECM's data stream because I haven't seen zeros with any other system.
It's not as bad as I made it sound. I've got several issues going on, so the DFCO settings are way down on the list of things to pick on. Bigger motor, bigger cam, bigger heads and idle transition is pretty shakey. It turns out my wideband readings in EFI Live were way off, so I did some bandaid STFT tuning in the interim.
Blower is in bypass mode, so it's probably not that. I'm running catless now so you can hear everything. When fueling comes back on, there's a distinct "blorp" but nothing severe or unnerving, and certainly no worse than it was on the factory DFCO maps.
ok so just make the transitions not as bad... i will check that out and change them a little
sorry to be late to the party but here goes my questions/observations.
Car = 04 Holden Monaro/Pontiac GTO with capa Long tubes, miltek sport cats, miltek cat system
I've gotten my VE dialed in and now gotten my MAF mapped out to 1.00 +/- 0.01
Using the original Holden DFCO settings if I enabled dfco I could hear some unburnt fuel going into the cat and popping in there, rather than just getting the burble you get out of the exhaust exit. I quickly pulled over and turned it off for now but I have just applied the settings shown in this thread to my map (but kept the enabler temp high to stop it working yet).
My questions are this:
1.) Do the M6 cells refer to the manual six speed of which my car is? If so are the settings listed above for the Auto? For now I have kept the M6 settings as they were.
2.) I am running open loop + maf, both stft and ltft are disabled. Will this effect to the detrement of the car, the effect of DFCO?
I think that is it, basically will those settings be ok to try with a six speed modified manual? I'm eager to try it out but want to make sure it should be ok first. Also could someone confirm if the M6 does indeed refer to manual six speed cars - if so in the pasted settings why do they appear off?
thanks
edited to add my tune: http://www.stigmundfreud.f2s.com/tuning/olmaf.tun
also the log just in case: http://www.stigmundfreud.f2s.com/tuning/logs/olmaf.efi
The DFCO M6 is in additional to the general DFCO controls which are still valid on an M6 vehicle. The DFCO M6 becomes active (assuming the enables are hit) when the clutch is pressed in between gear changes.
I used to get some pretty spectacular popping in the exhaust with the default DFCO settings. I still do if i really nail it to beat a red light ;)
In my case this was markedly improved by increasing the values in the B3334 & B3335, basically reducing the ramp in/out times.
well going to give dfe1s settings a try - it was only under larger decels where the unburnt would go into the cat - ie 2nd or 3rd gear and letting it go down from 4000rpm.
Will see tomorrow, tbh I cant see dfco really saving me much but that lovely lovely sound it makes ;)
dont suppose you could whack up your m6 enablers could you tordne? I'm going to run with dfe1's settings this afternoon and so long as I get no fuel popping in the actual cats I'll look at the m6 ones too
You need to post this up over at the LS1GTO site. Despite the rantings of myself and others, there is a persistent belief that the best way to eliminate popping on decel is to defeat DFCO altogether. Hmmmm. Have the decel mixture so bloody rich it couldn't possibly ignite by itself. Brilliant.Quote:
Originally Posted by Tordne
Of course none of this is available on US based LS1 cars, correct?