edge04

iTrader: (9)

I know when tuning using fuel trims you want to disable things like MAF if tuning VE or DFCO, PE, etc. etc. based on your set up.

But when tuning using lambda error can't you just leave everything as is and tune the error from what you are commanding? I always disable fuel trims from the scanner so I'm in open loop.

I'm going to give my first shot at tuning a VVE tomorrow using Bluecat tool. Looks like I have a good starting point due to other peoples hard work and file.

eaglegoat

If you're really good you can just leave everything as is and tune. But (and I'm not being a jerk) you will want to tune sd and maf separately.

edge04

iTrader: (9)

Not a jerk comment at all. Figured you should tune them separately. However have you ever noticed one or the other going off once you enable them both?

eaglegoat

I tune them both at the same time. Set open loop and go. I've never had a problem with running open loop fueling. To answer your question directly, no. I've only ever had a problem with closed loop fueling. That can be fixed as well ;-) .

edge04

iTrader: (9)

ah so you were saying that I should tune them separately however others can tune them together..now I get you "not being a jerk" comment lol.

I'm realizing tuning using LTFT if I do them separately I can get them good but then mixing them they go off again. I do wait for them to relearn after a reflash and log then.

So was thinking about just doing as you suggest, open loop and go. Can tune MAF, VE and WOT together.

So how do you fix the other?

eaglegoat

I can't give out all my tricks.

What you'll want to do is:
1. Set open loop
2. Set MAF only/Set SD.
3. Tune corresponding table.
4. Switch airflow mode.
5. Tune corresponding table.
6. Set hybrid mode, check logs.
7. Set closed loop, check logs.

edge04

iTrader: (9)

Thanks. Confirming this is the right lambda error function. Using this will give me error in percent and then I can paste multiply by %

100*([AUX.20121]-[USER.9004])/[USER.9004]

eaglegoat

You'll have to define the aux and user for me.

Exidous

iTrader: (11)

If you are seeming them with low error separately and higher error together I'd be inclined to look at your MAF table. They problem is they are not agreeing. The MAF isn't very accurate at low air flow. Especially idle.

edge04

iTrader: (9)

AUX20121 is my NGK wideband I set up and USER9004 is my commanded lambda. My commanded lambda is PID6001/14.20

only thing is I am using V/10.2 + .62 for my NGK transfer function to display lambda in HPT. My stoich is set to 14.2

eaglegoat

Your pid for lambda error is correct. Your pid for commanded lambda will work, but I wouldn't use it. Move away from afr, think in lambda and in terms of lambda. EQ ratio maybe...

edge04

iTrader: (9)

PID.68 is commanded EQ ratio so can I use 1/[PID.68] or [PID.68]/14.20

eaglegoat

1/[pid.68]=commanded lambda

edge04

iTrader: (9)

well that gave a weird reading lol. guess I need to mess with that. my old PID gives me a commanded lambda of 1 in my scanner.

I did log and happy with my fuel trims both in MAF and VE running them together. Made a WOT pull and a little rich so adjusting that.

Next I have a cold start issue I'm messing with. Warm/hot starts are fine, but overnight cold starts cranking are rough. I loaded the stock Idle startup airflow vs ERT vs ECT and will see if that helps. Only had slight differences from it. thanks

eaglegoat

100*([AUX.20121]-(1/[pid.68]))/(1/[pid.68])

edge04

iTrader: (9)

assume this function will allow me to leave my scanner alone regardless of what fuel I run and will always command lambda? I would then only need to change the stoich value in the tune.

RonSSNova

iTrader: (3)

I use 1/EQ Ratio for Lambda as well. Works perfect.

eaglegoat

Winner, winner, chicken dinner!


Bonus tip: I use 14.12 for e10 stoich

Edit: I just saw your other thread and that you're running an e38 controller. For the E38 and newer controllers commanded EQ is the same as commanded lambda. In that case you want to use
100*([AUX.20121]-[pid.68])/[pid.68]

edge04

iTrader: (9)

I hate the "may contain up to 10%"

Our gas around here is so inconsistent. You can get pure gas but its only 91 octane. All 93 is the "may contain" so I split it

eaglegoat

93 octane is 93 octane. I'd run the 93 personally. Even if it's a little less than 10% that's why we have fuel trims. I'd rather be a little rich than lean.

Make sure you verify your wideband ground and offset every time you tune with lambda. Turn the key on, start the hpt log and put power to the wideband. The afx outputs the lambda voltage for like 10 seconds during the 20 second power up sequence.