I’m having some start up, idle, and coast down issues

[ss44]

[RWTD]

Your fuel trims are deadnuts perfect at both idle and cruising. Time to dial in the WOT portion of the MAF tranfer.

The surging is probably going to have to be some tweaks on the Base Running Airflow table, and/or spark tweaks. You also have a cam, keep in mind, so it should be expected to get some feedback from it at low rpms like that.

If you want to lower the idle lower, you really need to get a converter that isn't overtly tight. That will keep the car from pulling itself without having to apply much of any brake force at idle speeds of around 800 and 900.

BTW, why are you logging O2 voltages twice? Delete the ones out down at the bottom right of the "Table Display".

[ss44]

Thanks, again, twin o2s? Hell i don't know but my kids use my HPtuners on thier cars as well so they may have. Starting on the WOT now, since i poofed on already, shooting for 12.5-12.6 for WOT. I'll give up a little power for some safety this time.

However, first motor was a valve and piston coliding because of valve float not because it was lean.

So, what the best small stall? this a daily driver and i'm banned from the track for 2 years with this car (Wife). Not all lost, have a 1998 LQ4 jimmy for the track now.

[RWTD]

I believe I set your PE table to 12.6, so make sure that you dial in the MAF transfer to whatever the "Air Fuel Ratio Commanded Hi Res" says.

[ss44]

no clue what you just said, i have always edited the PE table. Looking for search button now.

[ss44]

Search button did not help...Please explain

[RWTD]

Okay, here's what you should notice with my tune:

The PE table is set to a constant value. On your vehicle that is 1.1670, which translates to 12.6. How does it do that? Go to General, Fuel Control, Stoich AFR, and you will see that this table is set to 14.699707, which is basically the stoich of 100% pure gas (if you are using E-10, then this value needs to be modified to roughly 14.1 - read below for an explanation of what "stoich" is). Therefore, 14.699707 is the AFR that the pcm will Command when your car is in OL (Open Loop - when the O2s are NOT functioning) & is the target AFR that the pcm attempts to achieve in CL (Closed Loop - when the O2s are functioning), but in CL it's also dependent upon the fuel you're using, so the fuel trims will ultimately decide your stoich operating point. However, there are modifiers that can come into play. Most notably is PE mode (Power Enrichment, aka WOT), which modifies Commanded fueling in OL. When in PE mode, to determine the new OL Commanded fueling, you take the stoich value and divice it by the PE value. Therefore, 14.699707 / 1.1670 = 12.596149957155098543273350471294 (12.6 for short).

So now when you look at your scanner, you will see "Air Fuel Ratio Commanded Hi Res", and at WOT this should show 12.6 (on the tunes I have made for you). Therefore, your goal is to calibrate the MAF transfer table (most likely just the High in your case) until that Commanded 12.6 value is your Actual AFR as measured by your wideband. Once you do this, regardless of what happens with the weather, your Commanded fueling will always be Actual. If you just "rape" the PE table instead, then your fueling can/will change with weather changes, and your spark lookup points on the Y-Axis (displayed as "Cylinder Airmass (g/cyl)") of your spark tables will not be true, as the MAF tells the pcm how much airmass is entering the engine, and this is crucial for Load/VE calculations for proper spark lookup, idle lookup, fueling calculations, etc, etc, etc! So, once you dial in the MAF transfer, then whatever you change your Commanded fueling values to, then this will also be your Actual fueling. Neat huh? Yes, the MAF is where its at!

Okay, this is just a "basic" lecture in simple Layman's terms. There's way more in-depth readings that you can search for.

So what is stoich? From Wiki:

Air-fuel ratio (AFR) is the mass ratio of air to fuel present during combustion. When all the fuel is combined with all the free oxygen, typically within a vehicle's combustion chamber, the mixture is chemically balanced and this AFR is called the stoichiometric mixture (often abbreviated to stoich). AFR is an important measure for anti-pollution and performance tuning reasons. Lambda (λ) is an alternative way to represent AFR.

[ss44]

Ok, maybe I'm retarded. But i don't understand how to set this up. I have read and read but I'm even more confused. I need this explained step by step. Sorry, i have always "raped" the PE table and i don't even know how to get the histogram set up for this.

I am including my current config as i set ones config effects this process.

Sorry, but thanks for helping.

[ss44]

Are there any e40 idle adjustment instructions out there. RWTD got it much much better. but looking to fine tune the idle.

[ss44]

RWTD,

Here is what i came up with...looking for a review. Let me know if you need any logs or anything.

[RWTD]

That's not so bad for you being new to MAF tuning. However, a lil bit of advice:

Whatever your highest measured Hz is, make absolutely sure you ratio the REMAINING cells by the same amount of the last cell you ratio. Notice the huge spike at the end on yours?

Also, there's quite a few non linear cells evidence by the graph mode. There should never be that type of "spikiness", if you will, between cells. Work on your interpolation and smoothing of those areas.

[ss44]

now this is kinda funny. Got it idling pretty well, changed K&N to Vararam, and now it won't start for shit. More to come.

[ss44]

Doh, unplugged my LPE box while installing the CAI.

[RWTD]

I'm actually tuning a GTO today with a Vararam. We're using 42# Ford (green top) injectors, however.

[RLSEBRING]

I'm actually tuning a GTO today with a Vararam. We're using 42# Ford (green top) injectors, however.

So how did this tune turn out?

I have an LS3 Hot Cam I am still working on.

[ss44]

idle still just a little off, but its about 95% done. Been busy and just dealing with it lately.

[RLSEBRING]

idle still just a little off, but its about 95% done. Been busy and just dealing with it lately.

Is your test5 the latest? I want to compare what you have did to my tune and see where I am off.

[ss44]

yes

[rpturbo]

Wow, I applaud the help that was given to ss44, and this is an informative thread for a newb.

[EagleMark]

He sure was helpful and informative!

At the point where the thread died... wifey should have wrote him a check! Not only for getting his car tuned but for the Tuning lessons he got!