Driving is MUCH more pleasurable withOUT DFCO!!!

[the Dragon]

Disabled it because it was ANNOYING.

I go decently lean off throttle anyway.

80*F, sunny, no clouds, t-tops off, light ocean breeze and Playboy Bunny in the passenger seat with 6.6 liters roaring through Kooks and a Corsa :)

[swingtan]

I'd you tune DFCO to work correctly. Going lean on overdrive without removing spark is probably not great either. You are still burning fuel, but not enough so the exhaust temps will still rise a lot. I've set up DFCO to come in very quickly when cruising and to ramp out gently. I find it very good and enjoy the additional engine braking on long down hill runs.

Simon.

[swingtan]

Sorry.... "Did you"...

[the Dragon]

I made changes to the temp, map, speed, enable time, etc.

Can you post screenshots of your changes?

What was irritating to me was the car would stumble getting back on throttle after DFCO activated.
Never thought to look and see if DFCO pulled timing off throttle; I was unaware of that fact.

[swingtan]

DFCO will pull both timing and fuel. When the tune is accurate on the fueling, there should be no issues with the way DFCO works. I've attached a log showing how DFCO runs in my car and I have no issue with stumbling etc.

Exact settings will change depending on the car involved, so it's better to understand the goals and techniques to make it work well. Firstly, here's the log.

10031

The steps to tune are....


Work on the fueling. Get both the VVE and the MAF (if used) as accurate as possible. This is very important as it's the bas on which everything else is based.
Set the spark timing B5149 / B5150 to reasonable values. I don't like lots of exhaust backfires, so I set mine to 10' across the board. You can go lower, even negative values, but you will get more "snap, crackle and pop" as you enter DFCO.
B5148 controls how fast the spark comes back up to normal commanded values. I have high numbers for low TPS to smooth the feed in of power, but for 3% and up I have it as 50 pulses.
B2418 controls has fast the ECM transitions into the spark timings set in B5149. I have this set quite high 11500, so that the transition is slow.


The other settings, B2402-B2426 (under fuel-DFCO/CFCO) need to be set up specifically for the car. Throttle and airflow settings need to fine tuned as well as the injector timings. Depending on what is happening with your car and dealing just with the exit of DFCO, you may wan to increase the timing of the injector turn on.

Chances are though that most of your troubles will be fixed with getting the base fueling correct, As that's what usually causes issues.

Simon

[swingtan]

Sorry, it looks like the log didn't attach correctly.....

10037

[the Dragon]

Well since I'm having a lean fueling issue currently at idle I know I definitely need to address the VE.

I know very little about running MAFLESS but I wanted to attempt it rather than spend a couple of hundred dollars on a bigger maf and be a slave to it anyway :)

Thanks for all the info! I am going to look at the log and the parameters if I can nail down the lean problem later today.

[the Dragon]

DFCO will pull both timing and fuel. When the tune is accurate on the fueling, there should be no issues with the way DFCO works. I've attached a log showing how DFCO runs in my car and I have no issue with stumbling etc.

Exact settings will change depending on the car involved, so it's better to understand the goals and techniques to make it work well. Firstly, here's the log.

10031

The steps to tune are....



Work on the fueling. Get both the VVE and the MAF (if used) as accurate as possible. This is very important as it's the bas on which everything else is based.
Set the spark timing B5149 / B5150 to reasonable values. I don't like lots of exhaust backfires, so I set mine to 10' across the board. You can go lower, even negative values, but you will get more "snap, crackle and pop" as you enter DFCO.
B5148 controls how fast the spark comes back up to normal commanded values. I have high numbers for low TPS to smooth the feed in of power, but for 3% and up I have it as 50 pulses.
B2418 controls has fast the ECM transitions into the spark timings set in B5149. I have this set quite high 11500, so that the transition is slow.



The other settings, B2402-B2426 (under fuel-DFCO/CFCO) need to be set up specifically for the car. Throttle and airflow settings need to fine tuned as well as the injector timings. Depending on what is happening with your car and dealing just with the exit of DFCO, you may wan to increase the timing of the injector turn on.

Chances are though that most of your troubles will be fixed with getting the base fueling correct, As that's what usually causes issues.

Simon

Odd thing. I don't have any of those tables in my 2001 OS?

[swingtan]

lol... sorry, for some reason I though this was in the E38 forum.......

So I'm guessing it's an LS1 controller?

[joecar]

Simon,

Yes he has an LS1B...

but your comments are still valuable, you're quite welcome to start a E38 DFCO thread (or I can start one and copy your comments if you like...)

[the Dragon]

I just re-enabled DFCO now that the lean idle issue is resolved. I did the whole Skip Barber school crap years ago and I like to take corners hard and do "spirited driving" with lots of rev-matched downshifts.

As long as it doesn't interfere with downshifts I'm keeping it :)

[swingtan]

OK.... LS1 (COS-03) version.....

The steps to tune are....

Work on the fueling. Get both the VE and the MAF (if used) as accurate as possible. This is very important as it's the bas on which everything else is based.


Under "Spark-DFCO"
These parameters set "how" the PCM transitions between DFCO and normal driving

Set the spark timing B3336 / B5937-B5939 to reasonable values. I don't like lots of exhaust backfires, so I set mine to 10' across the board. You can go lower, even negative values, but you will get more "snap, crackle and pop" as you enter DFCO.
B3335 controls how fast the spark comes back up to normal commanded values. I have low numbers (0.2)for low TPS to smooth the feed in of power, but from 20% I ramp up to 0.8 at about 60%.
B3334 controls has fast the ECM transitions into the spark timings set in step 1. Set quite low 0.011, so that the transition is slow.


Now on to the settings under "Fuel-DFCO"
These really set "when" DFCO is active

Most of the settings are probably fine as is. To tune the settings you will need to log a drive and use the <F> keys on the V2 to drop flags in the log. Flag when you feel DFCO should become active and when it should exit. The settings are fairly well documented in Tunetool so use common sense to adjust the settings.

I think you'll find that the base fueling will help a lot though.

Simon.

[the Dragon]

Now that I'm CLSD, I retract the title of the thread.

DFCO has not hindered rev-matched downshifting.

Bonus on gas milage lol!

[swingtan]

Good work!