Re: Looking for some tuning Help
How far along are you? Do you have a grasp of the general tuning basics? I'll be glad to help in whatever capacity I can, but my schedule is erratic and unreliable, so I'd prefer to keep my assistance to this thread. That way, I can contribute as I can and others can benefit as well.
Here goes....
I'm going to make some assumptions.
1) - You have an understanding of computer usage and are familiar with TunerPro.
2) - You have datalogging capabilites (best if they're incorporated into TunerPro).
3) - You have some AFR monitoring hardware. We can tune without, but it's better with.
4) - All of your hardware is connecting properly and you can datalog, emulate, etc... just fine.
5) - You have an appropriate starter bin for your mods.
Assuming all of that,
let's start with idle. The bulk of idle tuning is going to be confined to 5 tables.....F1, F13, F18, F19, and F29x. We'll start with F1 as it's fickle with Vortecs and being off in here can affect the other tables.
F1 - This is your base timing map for the entire operating range of the engine. From idle to WOT, data in here directly affects the overall timing advance/retard of the truck. This is not to say that the values in this table are the exact timing you will see with a scantool, but they are a part of the formula used to calculate overall timing, so they're just as important as any other. Vortec heads require more timing at vacuum and allow more timing in boost thanks to improved design. Due to this, we need to accommodate for them in F1. Typically, Vortecs like between 5-10 degrees of extra timing from 600-4800 rpm in vacuum. So, start out by making sure that your F1 cells look similar to the image below.
It's not important that your's look exact (these are from a truck at sea level, so YMMV), but they should be within 7-8%. I typically advise people to get the 600/800/1000 rpm cells at idle vac as close to each other as possible. Your idle may hunt a little bit and having timing jumping all over the place because you have the cells far apart can drive you mad. Likewise, the cells don't need to be far apart as the timing needed at 1000 rpm is of little difference than what the engine wants at 800 rpm. If your's were far off, you should begin to notice an immediate improvement in idle and cranking effort. Now, let's move on to the other tables, specifically F13, F18, & F19.
F13/F18/F19 - I'm going to group these together since their duties are so similar and the editing of one should be transparent to all (if not data specific, then margin specific). F13 sets a desired idle rpm based on battery voltage. This is so that if the charging system incurs an issue, that the ECM will attempt to compensate by raising the idle (linearly as batt-v decreases) to prevent the engine from stalling and to (hopefully) allow increased charging voltage. F18 & F19 are similar table based off of coolant temperature, allowing the idle to remain high while the engine is cold, and drop to normal idle speeds as it warms up. The 3 table work in concert, and if one is askew, the others are impacted to some degree. Let's get F13 straight first.....every truck is different and will like a different idle speed, but for the sake of getting a baseline, let's set F13 to look similar to this:
You'll notice that the value for 12.8v & 14.4v are the same. This is because your idle voltage should be somewhere in the middle of those two. As a result, the ECM will "blend" the two values. So, if we had 12.8v at 900 and 14.4v at 700, and your idle voltage was at 13.6v, then the ECM would command an 800 rpm idle based on the average of the two cells. if the voltage were to creep to 13.0v, then the idle would fluctuate up. We don't want this.....we want stability, so set the two cells identical and if you have a small voltage fluctuation, the idle will won't suffer. Now, let's set F18 & F19 for similar obedience.
The truck that the above values were pulled from liked a 50 rpm drop when put in gear. Your's may like more (75, 100, etc...) or it might want no drop at all. You'll need to play around in here when fine-tuning. The LH table is F19 - Idle RPM in P/N and the RH table is F18 - Idle RPM in Gear. Your's should be similar, but not necessarily exact. Your truck may like an overall higher or lower rpm and it may need cold weather tweaking. Again, YMMV. The important take-away is that the warm idle rpm in these two table are not drastically far from F13, and as a result, the ECM has an easier time resolving an accurate idle rpm.
F29x - Lastly, let's touch on F29x briefly. This is a (main) fueling table unique to code59 as it combines the 2D F30 table with the 3D F29 and F29c tables. As a result, we get a much more comprehensive (but not definitive) fueling table that allows us to see trends and desires in greater clarity. For this post, we're gonna focus on the idle section only, so open F29x and observe the following section.
The above values are from a truck running 75# injectors, so you may need to completely ignore these values, but that's not the important bit.....the trend is. The table needs to be edited in cooperation with a Wideband O2 in my opinion. Can you do it w/o one? Sure, but the time it takes you to get this table straight with a wideband is considerably less than without. So, with a wideband, you want to shoot for a fairly lean, stable idle. You want the idle lean to reduce emissions (if you care), increase economy, and keep plugs clean. SyTys typically like a slightly rich idle, so your inclination to set it to stoichiometric (14.7:1) would most likely be a bad idea as it may stumble and fart all over the place. 13.7:1 might be smooth as a Lexus. This is truly a custom tune in this table as it's dependent on SO many factors that can't be replicated on a bench. However, if you have the hardware (WBO2 wired into the ECM), I strongly encourage you to enable F29_AFR and tune based off of fuel trim. This is a lifesaver for the DIY-EFIer.
More to come.....
