VE table tuning philosophy - need help

[Cantalope Kid]

Can someone confirm my bullsh!t above?

I was under the impression the instructions in the editor (hit F1 key) were correct. They seemed to work fine everytime I used them.

[5_Liter_Eater]

Which part?

[Cantalope Kid]

Which part?

Basically I'm getting mixed signals on the Speed Density Tuning Instructions from redhatsupra's statement. I respect him something aweful and want to understand why he would question the method is all. See I'm miffed as my method comes from instructions included with Hp Tuners Editor. If it didn't work how would it make it into the stickies and in the Cd shipped with the equipement?

See my sig. to find the instructions with screen shots.

I don't see what could be wrong with the method? Worked for me on several occasions.

I recently had another respected local tuner whom I trust tell me that when tuning your VE table in OLSD to set my OLFA and PE to a matching 13.0 AFR = 14.63 AFR (stoich)/13.0 AFR (Commanded) = 1.125. He then said try to hit a single target instead of two different values under different loads...i.e. the instructions indicate hitting a OLFA 1.0 = 14.63 AFR at anything other than PE which I personally set set to a = 12.5 AFR when tuning VE table. Just wanting some peace of mind. I love to learn and enjoying helping those that want to learn even more. Every once in awhile I like to hear it from someone else too despite my own ignorance.

[redhardsupra]

the answers to your questions have could fill a book. make a list of precise questions and we should be able to tackle them one at a time.

[Cantalope Kid]

Question: Are the instructions on how to tune Speed Density posted in the Editors F1 help menu correct/up to date?

Redhatsupra: Got your PM. Thank you. We'll do!

[5_Liter_Eater]

I'm not sure which part of the instructions are up for debate but I don't see much of anything wrong with the guide.

Some small tweaks to the config like there is no need to log fuel trims if you're open loop and I prefer AFR Commanded Low Res if it's available.

Disable DFCO, good.

Set commanded AFR across the board in PE, good.

Set OLFA = 1, ok.

Disable fuel trims, yep

Disable COT, ok

Copy HO spark to LO spark, good

Fail the MAF, good. Unplug it, na. I don't like unplugging the MAF. Disable it and verify P0103 DTC is set. Too many vehicles with integrated IAT's and this is a VE tuning for dummies guide so there are some who would unplug the IAT.

I think 50 cell hits is dos mucho but thats personal preference.

I would add disabling VE to the MAF tuning part by setting the high RPM disable to 0 but this is a fairly new concept.

All and all I'd say its one of the better guides I've seen.

[364TA]

Fail the MAF, good. Unplug it, na. I don't like unplugging the MAF. Disable it and verify P0103 DTC is set. Too many vehicles with integrated IAT's and this is a VE tuning for dummies guide so there are some who would unplug the IAT.
.

I did that the first time.

<<<< Dummy.

Great thread.

[bcar]

[slammin86]

So us newbies just need to throw the CPIG deal in the circular file?

Hmmmmmmmmm?


Jim

I too would like an answer to this question. I actually found this document earlier today and thought it was an informative how to for us that are new to hp tuners.

http://www.lsxconversion.net/cms/doc...%2016JUL07.pdf

[5_Liter_Eater]

It's long so I only scanned it. There is some very good info there but there is some bad info there too. Like:


- Disabling PE and trying to tune the entire VE table with fuel trims commanding 14.7:1. :O This is bad m'kay?
- Pasting special, add to VE instead of multiply by %. Fuel trims and AFR error are a percentage, doesn't make sense to add. It references multiply by % in a few other areas so this may be a typo.

Again I only scanned it but there did seem to be a lot of useful info there.

[superwagon]

I have read thru this about a hundred times and I am trying to follow the speed density wideband instructions. If I set olfa table to all 1.00 I will command 14.681 afr at all points and the stock settTings all 1.00 at like 160 degrees and higher so I dont see the point in changing the lower temp ones to command 14.681. It also says to add 15% to the ve table that I am trying to adjust to correct afr error? So if I do that and go log err % and then I will find that my ve settings are at least 15% off do to my original adding of 15% plus however far off the factory ve table was. Then I will paste multiply % my error into ve table and do another log. (wont this just be bringing me closer to my olfa commanded 14.681 afr? This just seems like you would be tuning your ve at a lean condition? I also see in the instructions to change your pe values to command a richer afr. That sounds okay to keep afr from being too lean in the upper rpm/load areas I guess but if I follow these instructions for tuning my suburban it does not matter what I change my pe eq ratio to because the factory does not allow pe until after 5000 rpm and my rig does not ever even get to that high rpm. My wot shifts are at 4700. So if I follow these instructions I will be commanding 14.681 at all load points and trying to correct my ve table closer and closer to 14.681 with every afr err correction to my ve table. My factory ve table is actually off by - numbers so fortunatly at this point I have been a little richer than 14.68. It seems as though I would be better to change my olfa table above 160 degrees and pe tables to command say 12.5 and then I could correct ve table err all while running at a safe 12.5 afr? Does that make any sense or am I still not getting it?

[69lt1bird]

Try these, they are still work in progress but I have not been told that they do not work. There is always room for improvement so feedback is good. Some day I will get more time and add more stuff.

SD VE and MAF Tuning Instructions rev2.pdf

[JimMueller]

Try these, they are still work in progress but I have not been told that they do not work. There is always room for improvement so feedback is good. Some day I will get more time and add more stuff.

Page 13, step 2 and Page 7, step 12 need touch-up: The temp in this table is the temp when closed loop is activated. If you set it to 284, it'll never be activated. So page 7's table description should be something like 'Table used to force Open Loop Mode', and page 13's table values should be put back to stock (presumably). Also need to fix table in page 17, step 11 if you want it to reflect the what the new values should be.

I also prefer to turn off LTFT's so I don't have to keep clearing them before each scan, instead working solely off STFT's.

Other than that what you have so far looks good to me. I'd like to see something in there about how to properly alter ETC Area for cable & drive-by-wire and how the spark tables should mesh together.

[69lt1bird]

Use Rev2 in my post #52, delete the link to the old on in you post.

[The Alchemist]

I think what RedHardSupra is getting at with the OLFA is, there is no need to tune in open loop. Let the engine come up to temperature first, go into closed loop, which commands 14.7:1, then log your data. That's what I do and seem to be faily succesful with it. PE still works, and I'm logging the AFR % error between commanded and actual.

[Frost]

I think what RedHardSupra is getting at with the OLFA is, there is no need to tune in open loop. Let the engine come up to temperature first, go into closed loop, which commands 14.7:1, then log your data. That's what I do and seem to be faily succesful with it. PE still works, and I'm logging the AFR % error between commanded and actual.

You can't VE tune with a wideband in closed loop...

Setting the OLFA to 1.0 when the engine is up to full temp keeps the car from constantly changing commanded fueling vs. load at cruise. Everytime it changes, there is transitional error that gets logged. Commanded AFR changes and there are a few frames in between before the WB catches up. These cells will show high % error but it's NOT REAL, it's latency. When you later try to apply this error to your VE, you will be putting this error back in.

I'm not saying to LEAVE the OLFA at 1.0 with a warm engine, just use it to tune. I actually use 1.02 in the OLFA for tuning and then set it back when done.

[superwagon]

I guess I am not understanding the recommended changes to the OLFA table for tuning VE. My stock file is set to all 1.00 at anything above 158 degrees already. If I fill all cells with 1.00 the only thing that will change is my warm up will be leaner at 14.681? Also following all of these tuning instructions the end result is commanding 14.681 from the second I start my truck all the way thru WOT PE at 4800rpm all while correcting my VE table to match my commanded afr leaner and leaner each time.

[69lt1bird]

Not all cars come with that table like yours, that is the reason. You are commanding stoich with no additional adders while in open loop.

Your PE table is still being used.

I am not sure I understand your problem?

[superwagon]

My stock PE does not enable until 5000rpm and my max shift points are at 4700rpm, so I'm never getting to the 5000rpm enable point. Should I lower my enable rpm for tuning VE table, if so to what?

[ChevyHighPerformance]

After you've tweaked your VE and MAF, your engine is calibrated to your wideband not to your precat O2's. As an exagerated example, if your Ltrims all converge to +10, this means that your precat O2's are "off" by 10% from your wideband. One simple way get back to your real commanded A/F, is to scale the commanded A/F. For this example, your real A/F is 14.7/1.1. To get back to a real A/F of 14.7 you'll need to mulitply your commanded A/F by 1.1. You'll have to keep this in mind for your WOT A/F. This is one way to get everyting back, but probably isn't the best way. This was just to make you aware of a potential difference when you go back to closed loop using your precat O2s.

I have seen many people without widebands disable the MAF and use a table that plots Ltrims versus RPM and MAP and use this table to scale the VE tables. Then enable the MAF and plot Ltrims versus MAF Hz to recalibrate the MAF curve. I get a feeling that I'm going to get some grief about not using a wideband. However, using the posted procedures, you are going to rely on precat O2s eventually.