Modified DFCO settings - not getting expected results

[Kevin Doe]

I finally decided to modify my DFCO settings and tables. After making some changes (suggestions made by TAQuickness) I went out and did some testing and logging on my work commute. I'm getting some unexpected behavior. Maybe I just don't have a full grasp of how it all works and someone can help me. Check out the information.

Here are my settings.

http://i93.photobucket.com/albums/l55/Kevin_Doe/RX-7/DFCO5.jpg

http://i93.photobucket.com/albums/l55/Kevin_Doe/RX-7/DFCO6.jpg

http://i93.photobucket.com/albums/l55/Kevin_Doe/RX-7/DFCO7.jpg

http://i93.photobucket.com/albums/l55/Kevin_Doe/RX-7/DFCO8.jpg

http://i93.photobucket.com/albums/l55/Kevin_Doe/RX-7/DFCO9.jpg



I have attached my tune file and log file if that helps as well.

[Kevin Doe]

With that said, I went and logged. It seemed like the DFCO wasn't turning on when I thought it should have, and it did not seem consistant. Here are some plots from my log.

Turning on like I expected.
http://i93.photobucket.com/albums/l55/Kevin_Doe/RX-7/DFCO1.jpg

Not turning on like I thought it should have.
http://i93.photobucket.com/albums/l55/Kevin_Doe/RX-7/DFCO2.jpg

Not turning on like I thought it should have.
http://i93.photobucket.com/albums/l55/Kevin_Doe/RX-7/DFCO3.jpg

Turnin on like I expected.
http://i93.photobucket.com/albums/l55/Kevin_Doe/RX-7/DFCO4.jpg


I cannot figure out why it did not turn on those two times in the screen shots. There was about 100 other times I purposely let off on the highway to try and test it and it didn't turn on like i would have expected. If someone can show me that light that would be excellent!

[Kevin Doe]

Another question, why am I getting anywhere from -6 to -10 degrees of timing when DFCO activates. My DFCO timing table shows nothing in the negative.

[NASABlue]

I think because the AF goes so lean after a shift due to the dfco.

I really don't know too much though, I know why it was happening to me but I never had any luck with getting it straightened out. Car still runs like crap, annoying as hell

I think someone replied that at least I'll be saving fuel, which I appreciated.

Probably tell you to look at a tutorial or something:angel_innocent:

[NASABlue]

I tried setting the activation tempature for the dfco peramiters to 300 deg C or something

I never saw a way to turn it off.

Let me know if you find out.

[Kevin Doe]

I think because the AF goes so lean after a shift due to the dfco.

I really don't know too much though, I know why it was happening to me but I never had any luck with getting it straightened out. Car still runs like crap, annoying as hell

I think someone replied that at least I'll be saving fuel, which I appreciated.

Probably tell you to look at a tutorial or something:angel_innocent:

While I wholeheartedly appreciate your attempt to help me, you didn't really address my concerns. I understand what DFCO is for, and why I want it, its just not reacting as I'd expect. I know you're frusturated by not getting much help here, but like all things its a learning process. Many of your questions can be answered by searching. Sadly for me, I couldn't find anything addressing my questions.

[NASABlue]

I know, just trying to keep you up at the top while I'm monitering my post for responses.

I always find it's nice to have company rather than wait alone. I really did try the dfco turn off and wasn't trying to be an ass. I'm just trying to have some humor about the situation and though if I chimed in with my attempt and experience it would prompt someone to help because two people are looking to do the same thing. I totally respect your post and won't respond anymore.

Best of luck on this and have a great weekend.

Sincerely,

Ray
:cheers:

[johnv]

Another question, why am I getting anywhere from -6 to -10 degrees of timing when DFCO activates. My DFCO timing table shows nothing in the negative.

That will be due to table B3336

[Kevin Doe]

That will be due to table B3336

Let me reiterate. That table does not show any values that are less than zero, however I'm still getting negative values for timing.

[dfe1]

What are the values in B5915?

[JezzaB]

What are the values in B5915?

Thats the only thing I can see that would make the negative figures that low.

[roy]

Just learning myself here. But one thing that sticks out is, why is the rpm so high in b3309? It doesn't make sense that you would set it to 12800rpms. How would you achieve 12800 rpms to allow DFCO operation . I am probably not understanding something . To me it would make more sense to set B3309 to 1500rpm or something that is more reasonable.

[dfe1]

B3309 is for M6 DFCO- that's decel fuel cut during gear changes in vehicles equipped with a manual trans. I think Kevin's issues are with timing, not with the actual DFCO fuel settings. DFCO won't activate until timing is reduced to the value in B3336. (The description in the B3336 window is incorrect.) DFCO will activate at the B3336 value, but timing will continue to be reduced until it hits the value in B5915. If the timing ramp-in settings (B3334) are too slow, DFCO may not be activated because you're already back on the throttle before timing is reduced to the B3336 value. Factory ramp settings going into DFCO are typically very slow. Try using a setting between .04 and .08 in B3334.

[Kevin Doe]

def1,
Thanks for the explanation of how the timing works with DFCO. It makes sense now to me.

But, if you look at the four screen shots I put up, it doesn't really add up. On 1st and 4th screen shots you can see that the timing ramped down as it should, showing that even with the current slow ramp in rate it only takes a short amount of time. If you look at the 2nd and 3rd screen shots you can see that the timing never began ramping down. Can you help provide any explanation of why that never happened.

During driving around it seems as if the DFCO only ever turns on at low speeds, 1st, 2nd, and 3rd gears.

[Kevin Doe]

I konw there are some more DFCO experts. Help me out please. During more driving it really does seem like it only engages in 1st, 2nd and 3rd gears. I havn't felt it engage in 4th, 5th or 6th yet I dont' think.

[TAQuickness]

Couple of things come to mind regarding the enable disable.

Try setting:
B3308 = 138
B3309 = 9500
B3311 = 1
B3312 = 320

Table B3318, your enable values are higher than the activate values. Try swapping the values between the two columns.

Another note, I think it was SSpdDmn that noticed even though the re-enable timer was set to 1 second, it still took 2 or more seconds to reactivate. This on the 512k PCM. After his posts, I started to notice the same.

Is your car an ETC car? For some reason I have in my mind that there are two throttle position indicators for ETC (or it could be the side effects of my younger years causing this recollection). For the times you expected DFCO to enguage, the TPS indicates 0% but I'm wondering if that was the actual TPS position factoring TC and TF.

[dfe1]

Couple of things come to mind regarding the enable disable.

Try setting:
B3308 = 138
B3309 = 9500
B3311 = 1
B3312 = 320

Table B3318, your enable values are higher than the activate values. Try swapping the values between the two columns.



I don't think the above suggestions will solve the problem. All of the M6 values relate to DFCO during gear changes. Kevin's B3318 values should work correctly. Enable/Disable should be higher than Activate/Deactivate. When engine speed exceeds enable/disable, DFCO is enabled when all other qualifiers are met. Once activated, DFCO stays active until rpm drops down to the activate/deactivate level. Kevin's problems with DFCO appear to be related to ignition timing. In the areas of the log where DFCO isn't active, but should be, spark timing doesn't drop off as it should during closed throttle operation. Something is preventing timing reduction, and if spark doesn't drop off to the necessary level, DFCO isn't activated.

[TAQuickness]

I don't think the above suggestions will solve the problem.

Ideally they wouldn't. What they should do though is ensure DFCO M6 is not becoming active, or any part of the equation, without utilizing the maximum settings in the PCM.

For the active/enable, I'm following the line that you would enable DFCO before activating it, then deactivate it before you disable it. The MAP enable/activate settings follow this logic.

Again, these settings may not fix the problem, but should not worsen the situation either. Just one more thing to cross off the list.

[Kevin Doe]

For shits and giggles I tried the settings TAQuickness just recommended. No change. I still get it to work fine at low speeds (gears 1-3), and nothing above that (4-6).

The only thing I didn't do was to flip the values in the enable/disable activate/deactivate tables. I looked at some stock tables, and they are the same way. Any other ideas?

[dfe1]

I'm pretty sure the issue is timing. Can you think of anything in your installation that would be gear dependent? Since you don't have an original equipment installation, I'm wondering if there's something in the installation that's causing the problem. I'm running settings that are similar to yours in a few different vehicles, and DFCO works as it should every time you get off the throttle. If DFCO works consistently in first, second and third, but not in fourth, fifth and sixth, something gear related has to be interfering with the data stream that tells the PCM the vehicle is decelerating.

[Kevin Doe]

Nothing in my installation should be gear dependent. I have the entire GTO (2004 LS1) engine, transmission, engine harness, and PCM. The only things I don't have is the body control module (traction control, abs, etc). So far everything seems to work just as expected with the exception of this DFCO stuff.

[TAQuickness]

Try swapping the enable/activate columns. I know there are a lot of stock settings like this, but it's one more easy thing you can try to get marked off the list. Better to rule it out then not consider it.

After that, lets move on to the electronic throttle questions.

[Kevin Doe]

Try swapping the enable/activate columns. I know there are a lot of stock settings like this, but it's one more easy thing you can try to get marked off the list. Better to rule it out then not consider it.

After that, lets move on to the electronic throttle questions.

Sounds good, you are right, I should at least try it to rule it out. It doesn't make sense to me that they're backwards either. I won't be able to try it out again for at least a week or two. I just got a leak in the core of my radiator. Back to the radiator shop for replacement and/or repair. This has been the best $800 radiator ever.......

As far as electronic throttle. I have a mechanical pull cable throttle just like all other LS1s. The car did come equiped with some sort of electronic throttle cable system. I think it would override the manual input in some cases but not real sure. I removed it and until now it seemed to be consequence. I doubt that its the issue but you never know.

[TAQuickness]

good ETC shouldn't be an issue then.

dfe1 - On the spark topic - I'm not sure I follow you 100%. I've not realized anything in B3334-6 to resemble a spark limit/enabler. Difference between a 512 and 1024 PCM? Taking a closer look at the logs, I'm leaning more towards the idea of signal or communications interuption.

Kevin - Can you establish for sure DFCO is only working in the lower 3 gears or is only functional under a certain speed?

[Kevin Doe]

Kevin - Can you establish for sure DFCO is only working in the lower 3 gears or is only functional under a certain speed?

I'll have to add gear to my logs, and just drive aroudn trying to turn it on at verious gears and speeds and see what I find for sure. But like I said, that is gonna be at least a week or two out from now. I'll keep you guys updated.