Speed Density & Manual DFCO

[Gutless]

This is my first time really SD tuning a boosted LS. I have a good amount of experience in tuning my l67 car.

Setup is an lq4 with 2 Bar SD GTP Map, t56, 01-02 harness with early DBW, ls2 DBW TB, GT500 M122 blower at about 11 PSI, AEM wideband feeding through the EGR and a custom PID. It is a 01 sierra 5.3 411 pcm with the engine side tables copied over from an Escalade and a 4th gen F body data segment swapped over for the trans tables. I went through and followed the SD tuning how to adjust your tune thread on the forum here somewhere. The engine side data for a manual was also pulled from like a c6 manual vette for the ls2 TB for the TB area and other stuff diferent from a 60e sierra tune.

I'm on hpt V3.

Car runs good when the ECT is cool but when it is at operating temp (190 ish) it starts rough and will always cut fuel off on decel, even though my DFCO enable temp is at 280 degrees. It's fine when I am on the throttle running but if I am coasting it shuts fuel off and when I push the clutch in it dies since it has no fuel. Same goes for in between shifts, I will let off the throttle to shift gear and it shuts fuel off entirely and when i let the clutch out again and roll into it, it will run. Basically if I am not on the throttle the PCM cuts fuel.

It also starts great when cold, but when at operating temp will die easily. I have bumped idle speed to 750 but still dies. When I try to start it will ignite great idle for 2 seconds and die. It wont idle until I give it 10% TPS or so and let it run for 15 seconds and then I can let my foot off the pedal and it will idle back to 750 fine. It will idle at 750 for 30 seconds or so but die eventually and then its the same show where it will start and die half a dozen times until I can get the TPS right and it stays running.

It didn't seem to run this poorly when I first had it running on the MAF.

So what I am asking is
1. How to I shut off deceleration fuel cutoff during decel and shifts
2. What setting do I modify so it doesn't randomly die on startup.

3. Lesser problem, I am worring about this after I get 1 and 2 solved so I can really drive and tune it. Also, no matter how much VE I take out of the table at low RPM, cruise, or idle during RTT mode, the AFR doesnt change. It runs pig rich 10.0-11.00 at low RPM on a stock 6.0 VE table. I take 30% off the VE and it doesnt do anything. In the boost seems OK, its a bit lean but at least it is in the general zone.

5-3-17 NO DC FO.hpl86GP_DBW_2Bar_nodcfo_5-3.hpt

Any ideas? I attached one of my logs and the tune.

Thanks!

[5FDP]

MAF dtc's are incorrect, all 3 must be set to fail on first error.

Your open loop EQ raio is at 1.17, no wonder it's always running rich. It needs to be set to 1.0 aka stoich.

You are commanding an AFR of 12.5 in boost, that is not good and thus why you are lean in boost. You haven't even setup your boost EQ ratio table. Change it to 1.270 to command around 11.5 in boost and those tiny 36lb injectors are not enough for the boost you are running. Timing goes negative under boost, another thing that's not good.

No o2 sensor information, no injector pulse width. Add those to your logs.

[dermotw]

Have a look at the idle startup airflows and delays/decays, probably they need tweaking;

Capture.JPG

IMHO, the friction values & decay have a much bigger impact on startup than the ones labelled startup(??)... I have even wondered if they are labelled the wrong way around, lol.

EDIT: and BTW your TPS never goes below 3.9% that I saw... so maybe your throttle blade (assuming its cable) is wound open but TPS not relearned or something? Anyway, you can't setup idle/startup unless thats ok first...

[Gutless]

I fiddled for the last week and ended up finding the EGR airflow table wasn't zeroed which was causing all my problems. It now starts and idles good, Fueling is a little off but I am working on it.

It is a DBW setup. I have no timing in it since my injectors are too small and I don't want to run out of fuel. They are GTP l67 injectors I had laying around. I will be going to 80's once this runs to a point where it needs injectors. I don't have narrowband 02's. Just the wideband. I bought the engine as a longblock and built it so I never had them. I always assumed narrowbands are unneeded with SD tuning?

My only real issue now is it always commands 12.5. It wont ever command a 14.7 cruise or richen up under boost What do I have to change so that actually changes?

86GP_DBW_2Bar_5-11.hpt5-11-17.hpl

[dermotw]

You should set those 3 MAF DTCs P0101 etc. to MIL on first error, as far as I know, nothing else (you have them at no MIL light).

I am not sure you are logging what you need to, that "air-fuel ratio commanded (lo-res)" channel isn't an option I have available. But I see that you should at least have hit PE and even then it did not change. If you don't have any WB, at least if the 02s are still there you can log their voltages and see if the fueling is changing. It seems to me (I'm no expert!) that you have got it setup as it should be, and your commanded afr does change initially as it starts up...

You can also test that the logging is doing what you expect by deliberately changing the basic stoich value away from 14.68, e.g. set to 14.0, and see where the commanded fuel goes, it should shift down by .68.

[5FDP]

Disable all the o2 sensor codes, cat diag codes and lean or rich codes if you are not using o2 sensors.

Speed density can always use o2 sensors, you can always keep closed loop active in speed density. It's up to the end user if they wish to use it and still make it act like factory.