08 Vette way to rich

[rpmextreme]

I have been reading up on the forums and trying to remove some fuel from WOT. No matter what I do the car continues to run at 10.6 from 2500 to redline at WOT. I set every table I could find to 1.00 and its still rich. Any advice???

tune attached

[flea]

Can you post some log files?

How do you know it's running rich?

[flea]

One quick observation after looking at the file, you have COT enabled.

[rpmextreme]

Im running it on the dyno. 3rd gear pull on a dynojet. I will try a run with the COT dissabled but i'm pretty sure its not it, As soon as its in open loop it goes to 10.4 and holds it all the way thru.

Is there a good setup (histo-config)for my VCM scaner that will read all the parameters on the 08, I havent sat down and took the time to get everything working.
Thanks for the input

[5_Liter_Eater]

You just need to pipe the wide band into HPT and set up a histogram to log the AFR error against the MAF tables. Then just copy and paste (multiply by %) the % error into the respective MAF tables. To make it easier, set your PE flatlined at whatever EQ ratio you want to command (13:1 = 1.13).

I believe there is a sticky with the gen 4 specific configs at the top of the gen 4 forum that should have these histos already.

[5_Liter_Eater]

We need more info on what has been done. What mods were added. In looking at the tune there is a lot that looks fishy.

The IFR table looks funky, although the table is different than on my '05, but it should still be a straight line.

You're PE enable TPS graph looks odd. It should start out higher and go lower as RPM's get higher.

Set your PE Enable RPM to 0.

Max out the PE enrichment rate.

As mentioned, flatline the PE at your desired EQ ratio.

[rpmextreme]

its a brand new 1500 mile 08 vette. All that has been done is a air cleaner setup. I will attach the stock tune.


base run made 350 rwhp at 10.4 afr

[5_Liter_Eater]

Jez, so all you've done so far is edit some of the tranny parameters and everything else is as is from the factory huh?

I took your tune and made a bunch of changes and then realized I couldn't save it. Drrr.

Try knocking 15% off of the entire MAF table.

[rpmextreme]

Yup. Havent changed much of anything yet. Just want to remove some fuel and make some power. And work the trans a little bit.

It also runs with -10 to -14 on the long term fuel trims. seems to be running rich all the way around....but runs like a scaled dog.

[5_Liter_Eater]

Damn, that is pretty damn rich from the factory. Not the first time I've heard of that though. Just wait until you lean it out!

[rpmextreme]

I hear ya....just need to figure out how to get some fuel out of it.

[5_Liter_Eater]

Try knocking 15% off of the entire MAF table.

[rpmextreme]

I'm gonna go give it a shot right now. I will let you know if it works.

[rpmextreme]

well I got some of the fuel out of it with 10% removed from the MAF table and tweaking on the PE table. Also noticed when you mess with the 1-6 gear torque in the torque management table you loose power at 4800 or so and above....returned those setting back to stock and the power returned...hmmm. either way Im off to street drive and set up the trans.

[RWTD]

You need to disable COT, and kill DTCs P0420/P0430. flea already suggested to you to do this. This is 100% your problem. You need to drop what you're doing, pay attention and listen to us, bud. One day you're gonna blow your car up if you aren't paying attention (I'll explain why in a few).

Futhermore, you have absolutely RAPED your PE table. This isn't how you tune. You command the fueling via the PE table by setting it to your "desired" fueling. You then tweak the MAF transfer until your desired becomes Actual. Datalog and use simple math to calculate the differences (or simply use one of the provided histograms at the top of this forum to let the software basically build you a correct MAF transfer).

Now, here's what's happening with your fueling. You have COT left on. It is set VERY sensitive on ANY GM. When COT kicks in your current commanded fueling will richen up, and up to a maximum of 1.21. So what this does is take your current PE value (for whatever RPM) and multiplies it by the commanded COT value. i.e. your current tune has your PE set to 1.08008 at 3500 rpms. 14.67822 (this is stoich in your calibration) / 1.08008 = 13.58xx commanded. If PE is commanding a full 1.21, then your new commanded fueling is 1.08008 * 1.21 = 1.3068968, which = 11.23xx AFR. See how easy this works?

Okay, use the attached file - I've taken the liberty to correct your PE table (I set it to 12.8 AFR) and COT for you (disabled). Do NOT rape the PE table again. Learn to tune your MAF transfer. It's not hard to do at all, and is the ONLY correct way for fuel tuning.

IMPORTANT: As was suggested to in previous posts above, absolutely do NOT modify your MAF table in that manner. Nothing against the gent above, but that is honestly dangerous to do, especially when your issue is simply the COT having premature ejaculation (lol). A 15% enleanment could be deadly when in combination with your current PE table and if the COT decides to not kick in. With that being said, the factory MAF transfer on the LS3 is pretty damn good as-is, and doesn't require much tweaking to get right (provided you diable the darn COT, LOLOL!).

Regards,

James

[RWTD]

Set your PE Enable RPM to 0.

Max out the PE enrichment rate.

Just a lil FYI, his particular vehicle's factory settings won't affect his PE transition. The "PE Delay" in seconds is already 0 on the V8 cars (HPT doesn't have this parameter, unfortunately), and his enrichment rate is already set to 1.

One can change it as to suggestion on this vehicle, but it won't make any difference. No biggie, tho, as it doesn't hurt to do "extra" things. i.e. On many vehicles I disable for TM settings than is necessary to fully disable it, hehe. Old habits die hard.

[rpmextreme]

I ended up setting the PE table to the correct numbers and tuned the maf table and got the results I was looking for. When I was messing with the pe table so drasticaly it was more of a test at the time to see if I could get fuel out of the engine. I loged the COT and dissabled them at one point and the vehicle was still very rich. Once I tweaked the maf table everything was fine. Fuel trims came inline and WOT was good. Thanks for all your input.

[RWTD]

That's great to know! Congrats on getting your tune dialed in. My apologies if I seemed a bit "rough" in my previous post.

I'm a bit shocked that your MAF table is as far off as it seems to be. I haven't ran into that on the LS3. BTW, I'm not sure what wideband you're using, but if it required calibration, make absolutely sure that it is. i.e. In the case of the Innovate Motorsports sensors, if you ever lose power to it then it will lose the calibration, and you then have to do a "free air calibration" on them.

Also, if you tuned the car ANY at all with the COT enabled, you need to disable it while tuning. Once you dial in the MAF transfer, then you can reenable it. However, NEVER tune the fueling with the COT enabled in the calibration.

BTW, I'm in Mobile. You're not so far away. If you ever plan on being down this way in the Vette, shoot me over an email to [email protected], or send me a PM on here. It would be nice to meet.

[andrewzpsu]

I don't see why you'd need to disable COT when the car knows what it is commanding then. Same idea with PE.

If you go WOT and then the car is commanding a 12.4 originally but a 11.3 with COT on, its still goin to take the error from 11.3 as that is what will show up on the commanded afr.

[BBA]

I really don't see how you could have been running the PE enable at such low MAP and low TPS settings, it would enable PE everytime you have the engine running save for the delay ramp up to 5000 RPM.

The way I set is to set enable MAP to about 10 kpa under WOT max for your altitude (usually around 80 to 85 Kpa), then set enable RPM to well under lowest stall RPM (or just under 1000 RPM for manual) and PE Enable TPS to about 30. The PE multiplier needs to be in the range of 1.176 to 1.20 (for a PE active AFR of 12.5 to 12.25)

Post your current tune so we can see for comparison now that you have it working better.