Newbie in deep

[benicakova]

99' frc vette ls1, cam, exhaust, ls6 intake manifold, aem wideband

I tried to take it nice and easy, swapped in a junkyard unlocked ecu, loaded a factory tune from the repository to verify parameters, enriched fueling by 15%, disabled close loop via coolant temp, as well as lt/st fuel trims. Figured i should be safe to run off the maf, dial in the curve and move on to VE tables. Except the big sticky hit the fan and Im frankly a bit too panicked to tap into higher level reasoning that might actually allow me to help myself. The car starts seemingly normal, after a couple seconds starts to sputter as stalls out. I have no idea what my wideband PID math is measuring in the scanner, the actual lambda readings were .8 when i started the car which held for a few seconds followed by a steady leaning until it sputtered out. I will fix that PID issue but Im terrified to even start the car since I dont know what the hell happened Ive attached my tune and the short startup scan, Sorry in advance for my dumpster fire introduction

[vettemakesemwet]

Fisrt, take the fuel back to 10% over. If still too rich, take it to 5% over stock. Rinse and repeat. You're beyond pig rich. That is where I would start.

My first start with my stock z06 after the wideband install had it running super lean at idle.

[kingtal0n]

my suggested changes at a glance

1. base set point for idle speed in neutral is 0rpm, change to something practical?

2. running idle airflow is also set to 0airflow for park/neutral. Did you look through the file? Look at every setting...

3. throttle cracker i would cut in half or nearly eliminate depending on the type of throttle body used

4. If you have a vacuum referenced regulator, I would reverse the IFR table so that as vacuum goes higher, the injectors flow 'more'(just reverse the two values on either end) this will help lean you out at light throttle positions. This trick can still be used for non-referenced regulators just be more cautious about using it that way.

5. I would reduce minimum injector pulse, or eliminate it, same with transient fuel mg set to like .011 or something lower than .015, default injector pulse to like .950, short pulse limit 1.2ms, short pulse adder .250 ish.
This is to help it run leaner just in case the ecu is putting a cap on the lower limit

6. reduce open loop F/A vs coolant temp vs map table so the highest values around 60*F is like 1.10 to 1.15, and slope down to 1.00 before 160*F

7. power enrichment enable map to around 77kpa-80kpa, and then lower the TPS threshold to something reasonable say 30% or 20% ish (test later)
In other words use the MAP to throw PE, not the throttle position. If there is any lean spot in the transition I would add it to the VE table as a kind of bump or spike rather than reduce the constrains on PE.


8. try to get dfco working when your through with all the other stuff

9. under spark -> advance -> base corrections, make use of the first and second table (AFR spark advance and IAT)
Use that to remove timing for high iat and add timing for low iat (plus or minus 1~ degree for now)

10. high octane map at the bottom row I would go 16* at 2000rpm, interpolate to say 20* by redline, then interpolate that up to the line at 0.52 cylinder airmass so it slopes down from around 31* to that bottom row you did first.

cliffs
the only thing I see that stands out is the zero'd out tables for idle speed (both of them)

The log showing timing is falling off so maybe also
11.under spark -> idle spark advance, eliminate the near zero numbers so the computer cant throw near zero timing at it
12. same thing in the high and low octane tables (Whichever you use)
13. under idle advance compensation there is nothing after -200 degrees, maybe fix that to at least lock at some final value.

As to the too rich. between open loop FA table and IFR you should be able to get close. I personally remove the maf and just tune the VE table and that served me very well $0.02

[kevin87turbot]

The MAF sensor is reading really high at idle...over 4000Hz. Do you have the OE MAF/air tube/air box? If so, put the MAF back to stock and start from there.

Here, try this. It's just a few changes that will allow it to run in SD mode. I changed a few things for you...

Make a datalog with this file and let us know how it performs.

CorvetteVEtunestep1.0.hpt

[benicakova]

"running idle airflow is also set to 0airflow for park/neutral. Did you look through the file? Look at every setting..."
-Yes, but i'm thinking i could have benefited from being a little more thorough (cringe)
Maddd Serious thanks for all tips, I had real Biden moment today. I'll go back into the repository and compare a little harder....

[benicakova]

The MAF sensor is reading really high at idle...over 4000Hz. Do you have the OE MAF/air tube/air box? If so, put the MAF back to stock and start from there.

Here, try this. It's just a few changes that will allow it to run in SD mode. I changed a few things for you...Attachment 97376

Make a datalog with this file and let us know how it performs.

I added fuel via multiplying the Maf freq table by 1.15, It was a temp setting but is there a better approach? I'm also seeing a commanded lambda of .75 in vcm scanner I assume that is due to engine temp relative fueling. And thanks Ill check it out!

[kevin87turbot]

"running idle airflow is also set to 0airflow for park/neutral. Did you look through the file? Look at every setting..."
-Yes, but i'm thinking i could have benefited from being a little more thorough (cringe)

All of the manual transmission P01 applications have 0 for P/N idle speed and airflow. That's not the problem.

Give this tune a try...

CorvetteVEtunestep1.0.hpt

[kevin87turbot]

I added fuel via multiplying the Maf freq table by 1.15, It was a temp setting but is there a better approach? I'm also seeing a commanded lambda of .75 in vcm scanner I assume that is due to engine temp relative fueling. And thanks Ill check it out!

No need to add to the MAF freq table...at least to start with.
The Base Running Airflow table is the one to add some additional airflow.

[55Belair]

You didn't mention if the car ran with the stock tune before you made any changes.

[benicakova]

I loaded a stock tune into the car and low and behold it runs (decently enough), a touch lean but it appears that my weak efforts to fuel off the maf had went awry. In spite of this, I'm seriously considering running a VE tune, what are the downsides?

[vettemakesemwet]

Car is set up to run "dynamic", meaning SD and MAF. I started with VE tuning and got it in line. Keep in mind mine is stock. After VE/SD, I tuned the MAF. Think I need a couple more runs on MAF tuning, and it will be done. Car runs 14.6-14.8 idle, 13.9ish accelerating normal, 12.5 ish WOT. I'm a realist. I can tell you the car responds differently, and can feel a little more push back in the seat when I get on it. The basic order I have found is VE/SD tuning, then MAF, then timing. Be careful on spark adjustments.

In short, after a certain amount of boost, you will need to run SD/VE only. Until then, use the MAF, it helps.

I would take the tune you have in now, force open loop, add 5-10% fuel to cover the lean spots, take out 5deg timing if possible(depends on cam and current settings). Then start to tune your VE map. Start gentle and work your way up.

[55Belair]

I loaded a stock tune into the car and low and behold it runs (decently enough), a touch lean but it appears that my weak efforts to fuel off the maf had went awry. In spite of this, I'm seriously considering running a VE tune, what are the downsides?

It seems that stock tunes being lean is common. From my experience I would suggest that you change one thing at a time rather than wholesale changes. I started with the VE tables of the stock tune and worked my way up through the MAF and timing after that. When I made mistakes and made the car run worse (and it did happen) it was easy to go back to the last tune that worked and try again.

Good luck