Black02SS

iTrader: (36)

I have been messing around and noticed that when you change back to the stock OL AFR Table, your air fuel ratio doesn't correspond like it should. ie. When you command a AFR of 12.96 (1.13) and get the cells to match, then switch back to the stock table (1.08-1.13) they are off.... I was under the impression that once you get the VE table dialed in to 12.96 (1.13) and set the table back to stock, all will fall in line. Why don't they?? I see this problem a bunch at idle. I had it set to 12.96 and now it is set to 14.7, but the AFR still shows 12.96 so my AFR % is off.

Black02SS

iTrader: (36)

Here is a screen shot of the only change made to the car. I was under the impression that the AFR was supposed to fall in line with the table. Here are the before and after screenshots. The only change was to the OL AFR Table.

Black02SS

iTrader: (36)

anyone?

405HP_Z06

iTrader: (11)

TTT, Anyone have any ideas?

WS6FirebirdTA00

iTrader: (33)

did you ever figure this out?

MeentSS02

iTrader: (11)

Damn it Chad...I'm putting on an 85mm truck MAF this weekend, and was just going to get a good SD tune on it until I can figure out what to do with the MAF table (as in I'd want to have HPT 2.0 with custom histograms).

You suck. Get this figured out. Can you verify you are in closed loop?

Black02SS

iTrader: (36)

I am in open loop as my car will never see closed again. The MAF table has nothing to do whth this as it is back to back tunes, just changing the open loop afr table multiplier. I still think it has to do with the air coming into the car and a calculation the PCM uses. My only recommendation is to set the open loop table where you want it and adjust accordingly. If you are using a wideband and setting the ve up with open loop, I would scale the VE table by a factor of 1.00(14.63) up to 70 kPa and 1.13(12.96) from 75kPa to 105kPa. This ensures you see a commanded afr of 14.63 at cruise and part throttle, but is still safe at 12.96 when you go WOT to tune.

MeentSS02

iTrader: (11)

Hmmmmmmmm...I guess I'm gonna try doing something a bit different from you then. I'm gonna try a closed loop SD tune (verify VE in open loop, close the loop and let it trim as needed, leave MAF fail freq. set at 0). My O2s seem to be doing alright for the time being...

MeentSS02

iTrader: (11)

I would also wonder what else the PCM looks at in addition to the Open Loop A/F table...have you tried setting the whole table to something like 13.5 (not just sections) to see if it gives you that? Maybe it interpolates kinda like the VE table with more than one value?

WS6FirebirdTA00

iTrader: (33)

are there any other hidden tables that would change it for conditions? like the ect correction and iat that we talked about?

Black02SS

iTrader: (36)

Reason I won't do that is how will it make a difference? You are doing the same thing essently, just a different approach. Regardless of how it is performed, you are still trying to achieve a afr of 14.63.

Black02SS

iTrader: (36)

Yup, same outcome. Once it is dialed in for a certain AFR, then you change it in the open loop table, it will be off.

Black02SS

iTrader: (36)

That I can not answer ATM. I have all of my extra tables zero'd out so that they won't come into play.

MeentSS02

iTrader: (11)

I understand where you are coming from, and in theory, you are right. I just think there is more to this story than that...I really need my software here to make any more guesses.

Black02SS

iTrader: (36)

Here is one of my thoughts on this. If you have a value in the VE table that is set inline with the Open Loop Multiplier, and then you change the multiplier, you have just changed the equation, whatever it may be. I believe it is all in the math portion.

MeentSS02

iTrader: (11)

Hmmmmmmmmmm...something is not right here. If you are commanding an AFR, you should be getting that AFR. Something is adding in to this equation somewhere...I'm sure it isn't your trims (that's too elementary to have slipped past you). Grrrrrr...let me think about this.

Black02SS

iTrader: (36)

When you are in open loop, you work off of the Open loop multiplier Table whatever that value may be. If you tune off of closed loop (oxygen sensors) you don't use that table, you tune off of stoich (14.63). So why would you tune in open loop for a commanded afr of 12.96(1.13) if you are going turn right around and throw it in closed loop with a commanded afr of 14.63? Why not just tune the open loop afr table too 14.63 to start so there isn't this issue. Granted, it doesn't really explain anything but just makes more sense to tune the car for the desired AFR the first time then the other?

WS6FirebirdTA00

iTrader: (33)

that sounds like a legit reason, so the comanded afr stays the same then? have you tried to change the ve in those spots and try to see waht it changes? i would think whatever you set it at it should hover right around there reguardless the ve settings, but it may mix it up. id like to see if the ve was decreased the same amount what woudl happen.

MeentSS02

iTrader: (11)

Hmmmmmmmmmm...something is not right here. If you are commanding an AFR, you should be getting that AFR. Something is adding in to this equation somewhere...I'm sure it isn't your trims (that's too elementary to have slipped past you). Grrrrrr...let me think about this.

MeentSS02

iTrader: (11)

I'm gonna do a closed loop SD tune so the computer can trim to compensate for the varying weather conditions on a day-to-day basis. The VE table will be dialed in in Open Loop though to keep the PCM from having too many of its grubby little fingers in the equation.

So, here's what I'll do:

1. Disable the MAF (fail freq -> 0), disable DFCO, disable PE.
2. Get the VE table dialed in to an Open Loop F/A of 1.13
3. Once it is dialed in with the wideband, I'll re-enable closed loop, but still in speed density (MAF fail still @ 0). Re-enable PE and maybe DFCO (depending on my mood).
4. Once I find a decent method for tuning the MAF, I'll get that back in line.