Idle Tuning - Unable to correct.

[cfelbi]

Bought a 2014 Camaro SS2. It runs great, except for idle. Tried tuning per the sticky in this forum, but had little change with fair large changes. Messed with PIDs, unable to change much. TPS is hunting. Have some swings in O2 banks that alternate. Definitely rich at idle, noticeable in exhaust. It runs great in all ranges, but idle -> very rough. Occasional 2-1 RPM drop. Any guidance? Did check for vacuum leaks. Attached running tune as bought, and scan at idle. If a longer scan is need, I can record again, let me know what you would want. I would greatly appreciate your help!!! This is my dream car, but the idle is driving me nuts. Sorry, I am new to auto engine tuning, but have been tuning all kinds of equipment for years, so hopefully it comes quick.

2014 Camaro SS2
Long Tube Headers w/ Hi flow cats
Magna Catback
Cold Air Intake
The way it runs suggests it is cammed. Dealer said no. (Ghost Cammed? Don't see an camshaft tuning from stock)
It has definitely been tuned, do not have stock file to start from. Tables are quite different from stock file available in repository (which I did not want to use).

[5FDP]

Is it a L99 engine or LS3?

The L99 would have come with AFM/DoD and VVT. If L99, it's got a camshaft installed because the VVT has been turned off and same with all the DoD settings and trouble codes.

The calibration doesn't look like much was touched to be honest. Lots of it is still stock. The airflow model is pretty far off though, just look at your fuel trims. Once it gets to closed loop they are showing that it's pretty darn lean on the long term trims. If that aftermarket cold air intake changes up the intake tube design and size, you must tune for that to bring things back in line. Invest in a wideband o2 sensor, you've going to need it.

[pmoore4321]

According to the VIN it's an LS3.

[pmoore4321]

Base Running Airflow, Underspeed/Overspeed, and ETC tip-in are the only changes from stock that I can see.

[cfelbi]

Thought I listed it, but it is an Automatic. So, should be L99. Its L99 by VIN "J"

[pmoore4321]

Does the VIN in the tune you uploaded match the car?

2: Canada Built
G: General Motors
1: Chevrolet Passenger Car
FS: Chevrolet Camaro SS (Manual)
1: Coupe, 2 - Door, Notchback (27,37,47,57)
E: Active Manual Belts, Airbags - Driver & Passenger, Front (1st row), Front Seat Side (1st row), Roof Side (all seating rows)
W: LS3 - Engine Gas, 8 CYL, 6.2L, SFI, ALUM, HO
0: Check Digit
E: 2014 Model Year
9: Oshawa #1 Ontario
BuildDate: 2013725

Why don't you just change the three parameters back to stock and see how it runs?

[cfelbi]

Did not catch the VIN mismatch. Odd. Gonna need to try to find block stamp. Don't have any stock files anyway. Wouldn't be comfortable loading a tune from internet, you know.

[cfelbi]

So, I'm dumb. I uploaded the wrong tuning file. The file I uploaded was a tune I was comparing to. Thus, the wrong VIN. Here is the real tune. I did find the intake manifold and throttle body were not torqued down to spec. That has corrected the fuel trims a bit (uploaded 2 logs), still have a rough idle and lurching when I feather brake and 2-1 downshift lurch is a bit worse now. EOI Target vs RPM is quite modified. Thinking this is the cause of the rough idle and strong fuel odor. Any thoughts?

[pmoore4321]

Why don't you just return the tune to stock and see if that solves the problem? There's a 2014 L99 stock tune in the repository.

[UTGS]

Just went through something similar with my 2010 corvette. E38 ls3.

Mostly stock tune other than timing and fuel adjustments. Car has long tubes and AA supercharger w/ larger injectors. No cam.

I think my idle tuning issue was mostly related to the larger injectors though.

I was able to substantially smooth out the idle by reducing idle spark advance from 13* to 8* and cutting the O2 error table down to about 1/4 what it was in stock tune. I also set the stoich AFR at idle to 15.1 to lean it out slightly.

What tipped me off was forcing the car into open loop in the scanner, and noticing the idle smoothed out near perfectly. It then dawned on me that the pcm was over correcting fueling when trying to oscillate the Idle fueling in closed loop, causing the car to go over rich at idle.

I had messed with all the idle tuning guides / proportional fueling etc but the reducing of O2 error table was a significant improvement, along with stoich AFR to 15.1 at idle.

When I tune i aim to leave as much as I can stock, or as close to stock as I can. I recommend loading a stock tune and adjusting based on your mods. Sounds like your car is nearly stock, should be easy to dial in.

[Hib Halverson]

(snip)
I had messed with all the idle tuning guides / proportional fueling etc but the reducing of O2 error table was a significant improvement, along with stoich AFR to 15.1 at idle. (snip)

What table did you use to change the stoich AFR at idle?

[Xjas]

OP, judging by your MAF and MAP at idle I'd say its cammed. 70kpa MAP at idle, MAF air flow around 12g/s and an idle speed of 750 indicates a cam to me.
My LS3 when it was stock idled at 550rpm, MAP around 45kpa, MAF around 7-8g/s.
Since your tune has both low and high octane spark maps the same I would say you need to start from scratch and retune it properly.