Hey all. I cannot figure out why my friend's Camaro will not enable DFCO on deceleration. I have messed with the cylair and throttle parameters because the car has a cam and supercharger on it. But not matter what I do, it won't enter DFCO. I attached the tune and a log for everyone to look at. Any help would be greatly aprpeciated.
2023-03-28 Checkpoint.hpt
23-03-26 11-37-35.hpl
Mine did this too. I turned off the LTFT Idle Cell Threshold VSS.
Still not sure why it was doing it, but it fixed my issue.
I'm not on my tuning laptop so I cant see your tune now.
Did you just set the enable and disable VSS to 0 for this? Mine was at the stock values which enabled at 2.5 and disabled at 3.7 mph.Originally Posted by marksrig
This is my current settings.
ENGINE - FUEL - OXYGEN SENSORS - LTFT IDLE CELLS THRESHOLDS
Enable TPS 0.0%
Disable TPS 0.6%
Enable VSS 255 MPH
Disable VSS 256 MPH
I'm curious if my idle trims will change over time but so far it just fixed my DFCO not working. Sometimes if the RPM's are lower, it'll only go to stoich, but not every time.
DFCO entry spark is below your min spark. It cannot enable like that.
This would enable your LTFT idle cells at any speed so long as you're not on the throttle. I don't understand why this would enable DFCO.
I did the same on a friend's C6 and his just goes down to the minimum and enables. In this car I'm having issues with, it doesn't pull timing at all. It's not like it pulls down to the minimum but then doesn't enable DFCO because the DFCO entry is lower. It doesn't even ramp down when you're off the gas.
The speed setting disables it.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
See how this one does for you.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
My dfco doesn't work either but all my settings are stock. I don't even know if the factory even meant for it to work in the first place. Since my engine it heavily modified does that change anything because like I was saying all my dfco settings are still set to stock shouldn't it be working somewhat or does it have something to do with the fact that I'm running a maf tune?
Camaro Tune.hpt
Camaro log.hpl
L99 A6 - DSS FX Forged Piston's, Eagle ESP L19 Rods, ARP Head and Main Studs, LS9 Head Gaskets, GPI SS3 VVT Camshaft, GM Performance Racing Lifters, CHE Trunnion Upgrade, TSP Chrome Molly Pushrods, BTR .660 Valve Springs, GM Hollow Intake Valves, Melling 10355HV Oil Pump, IR EGM-205 Oil Pan Baffle, CAI Intake, Fast LSXR Intake Manifold, Nick Williams 103 TB, ZL1 Pump, TSP 1 7/8" Longtubes with 3" TSP Exhaust, Mishimoto Oil Cooler, Tru Cool 40k Tranny Cooler, 3600 Circle D Converter
I'll give it a shot
No change. Same deal. Timing off-throttle goes to 20 degrees and just stays there. Doesn't ramp down at all, and doesn't enter DFCO.
So it is working? Cause that's how I had it set up to go into DFCO. After passing 3000rpms it should have dropped to 15 then 10 by 2000ish. Post another log.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
No. As I mentioned above, there was no change with the DFCO settings you recommended. I attached the log. As you can see, off-throttle the timing goes to around 20 degrees (which is close to the coastdown table value) and just stops. Doesn't ramp down to 10 and doesn't ever enter DFCO.
23-04-06 19-40-28.hpl
Did you try mine? Wont hurt.
OK, I see what you're saying. You're saying after adaptive idle spark control kicks in your left with 20 degrees of timing and it's not in DFCO.
You might want to combine what marksig did with the corrections I made for a better chance of it working. It should be going in with those changes. I'll have to take another look later and see if anything else stands out.
Did this start at any particular time or change made that would help point in the right direction?
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
I have not yet. I just sent him a new file with your suggestion to try. He's out of town until next week so he's gonna try it next week.
Right. I have never seen anything like this before myself.
Unfortunately, it didn't start at any particular time. My friend just bought this car, and it has had this issue the entire time. I cleaned the tune up for him, and he says it runs awesome. This is the only issue remaining, and I cannot figure out why the hell it isn't working. It's meeting all the conditions but never entering DFCO.
FWIW I have tuned a bunch of Gen 4 platform vehicles (and even more Gen 5 vehicles) and never had this issue with any of them. I'm going to try @marksrig's change. It doesn't make sense to me why it would work, but it can't hurt to try.
The enable TPS of .11 through most of the range looks to be too high, it has to be less than the set value to enable DFCO. In the log it looks like a closed throttle gives a value of 12.2% which is expected. In my '06 V I have set quite a bit more aggressive than the stock settings all around including the crank pulses so it goes into DFCO real fast and it's still smooth in transition and will DFCO right down to my 900rpm disable point.
Last edited by lowmpg; 04-20-2023 at 08:43 PM.
Another table that affects this that isn't in the DFCO area - the BRAF settings in idle airflow (in gear values) can't be too high or it won't allow DFCO. If the value is too high it won't allow DFCO to enable.
Also - ANOTHER one that messed with my DFCO was the speedo setting when I was trying to adjust for my larger rear tire to get my speedo in sync. When I adjusted the 'Dist' setting, which his is adjust way less than stock I believe - it adjusted my DFCO and it would not enable as before. Can't make sense of it but check it out! My 'Dist' value is 1245.78, same as stock on my car. FWIW that value does not adjust speedo on my car, I have a separate value for PCM pulses per mile.
I'm not a pro and have only tuned my car but really enjoyed getting it dialed in and found these things out.
Last edited by lowmpg; 04-20-2023 at 08:57 PM.
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