What steps to tune VE table in speed density mode

[sachem]

Hello all,
Guys, I’m looking for a straight forward description and procedure for tuning the VE table on a P59 ECU after it is put in speed density mode. What is the goal/objective? What am I looking to adjust? Am I adjusting the VE table to provide a specific A/F across the table? What data am I logging? What tables am I adjusting? I do have a wide band installed. After I get VE set, I will move on to the MAF. The engine is a 6.0L with 12587603 OS. I need to understand this. I'm not being lazy. I've put hours upon hours trying to figure this out. I don't want to quit and put a carb on the engine. It's been a long process to get where I am at. I’ve looked at other posts on the forum, but none give step by step procedures for this ECU family. You tube videos are somewhat vague. I hope this post is beneficial to all new tuners. As always, all help is appreciated.

Thanks
Tom

[Pulse_GTO]

What software are you using to log the computer?

[sachem]

I am using PCM logger and tuner pro

[steveo]

does pcmlogger spit out a csv?

i can teach you

[sachem]

It does, I'm here to learn

[steveo]

what is a ve table?

a table that represents how much air flows at a certain rpm and manifold pressure. so at 50 KPA and 5000 rpm it flows x air so the ecm knows how much fuel it needs.

what are you doing when you tune VE?

you are analyzing fuel errors against the ve table (rpm and manifold pressure) and correcting the errors in the VE table.

there are lots of ways to do that.

what is a fuel error?

your ECM targets an AFR. in closed loop that is 1 LAMBDA (or you can call it 14.7:1 but that isn't really correct except for pure gasoline). in open loop or power enrichment it targets an AFR from another table. to determine the fuel error in closed loop you look at fuel trims. in open loop you look at your wideband.

so in brief, your ecm goes 'okay, this much air (because VE is this) and inject this much fuel' and you measure the result to see how far off it is and adjust that cell.

simple ve adjustment:

lets say you are at 1000 RPM and 40 KPA and in closed loop, your fuel trim is like +10% (your ECM is adding 10% fuel to reach its target) that means at the VE table cell closest to 1000 rpm and 40 kpa, you would *1.10 (add 10% to that value)

sounds easy but hard, right? you have tons of data. people do it by hand but it takes FOREVER.

to tune your VE table properly, you have to use analysis tools like spreadsheets or programs like my trimalyzer or tablehack, or commercial tools. some logging programs have a 'histogram' built in that could do it.

do you want to try tablehack? it's kind of medium difficulty but i can walk you through, basically you load logs, tell it what your VE table looks like, tell it how to figure out if you are open or closed loop whatever (filters) and it tells you what your correction averages are. you can even do more advanced stuff like pasting your VE table and do some corrections.

if you wanted to give me a CSV log and show me your VE table, i could make you a step-by-step, and then you could reproduce it yourself?

[steveo]

by the way this might not sound easy but it gets super easy with practice, and then you can tune anything. tuning MAF is exactly the same as VE but easier because less dimensions.

[MO LS Noobie]

I am following with great interest. 4 inch stroked 6 L with the 603 computer and 4L60E. I've got it pretty close but trying to set up data logging so I can use the RT functions of tuner Pro. Jeff

[sachem]

Steveo,
Finally, put in simple terms- now that part is clear. So, do we have to keep the system in open loop to do the base tuning and then return to feedback and allow fuel trims to take over? I would like to try table hack, I want to learn this. As for a log file, I can send you one. The only issue I would have is that I can’t put the car on the road, not registered yet. I can give an idle log. However, Monday I am towing it to a friends shop to replace the oil pan and I could drive around the lot there. What parameters do you need to have logged? I installed my wideband through the EGR circuit on my ecu. So I would have to compare with wide band gauge to confirm they match. Steve, it’s starting to make some sense now.

[steveo]

the parameters you HAVE to log for VE tuning:

- MAP and RPM
- fuel trim or wideband afr (or both)

the parameters you SHOULD log, if available, without these your results will be crap:

- coolant temp (allow you to filter out log entries with a cold engine)
- tps (allow you to filter out transitional states like 'i just stabbed the throttle')
- power enrichment, open loop enable, closed loop enable, learning enable, or similar flags (allow you to use the same log for both closed and open loop tuning by filtering)
- AFR target (not necessary if you have an open loop or power enrichment target table that can be used, or if you just set a fixed power enrichment target and tune to that)
- o2 voltage (so you can make sure your o2s are cycling properly)

to tune any portion of the VE table you need LOTS of data from that portion of the table taken during real driving conditions

the only thing you can tune while idling is idle

driving around a parking lot will also not help

basically unless you have a dyno, you will have to plate the car to continue

but if you want to go over the procedure with a sample log just for learning purposes, a parking lot drive will do.

[sachem]

I’ll grab a log file while I’m there at the shop. Do I disable closed loop or allow it to enter into closed loop? That’s one of the things that confuses me. So many of the videos and forums say to not allow closed loop. I’ll set up my logger to capture as many of the parameters that I have available to me in the logging program. As I said, I really want to learn this, so whatever you ask, I’ll do. I don’t have a dyno, so I will have to do the best I can “on the road tune”, but at least I’ll know and understand the procedure.

[Pulse_GTO]

I’ll grab a log file while I’m there at the shop. Do I disable closed loop or allow it to enter into closed loop? That’s one of the things that confuses me. So many of the videos and forums say to not allow closed loop. I’ll set up my logger to capture as many of the parameters that I have available to me in the logging program. As I said, I really want to learn this, so whatever you ask, I’ll do. I don’t have a dyno, so I will have to do the best I can “on the road tune”, but at least I’ll know and understand the procedure.

If you don't have a wideband you will need closed loop activated in order to get feedback from the factory narrowband O2 sensors so that they may calculate the fuel trims. If you have a wideband then you want to log your data in open loop as the O2 sensor will be reporting the actual fuel ratio and the error can be calculated from that.

[sachem]

I do have a wideband.

[steveo]

if you have a closed loop flag in your log so we can tell if you're in closed loop or not then leave it on

[sachem]

Just checked, I do have a closed loop flag.