My PE table is commanding 12.88 across the board. During the log the commanded a/f is 12.88. But for most of the run my wideband shows 11.7ish. Why is this, what am I missing? In addition, why does it show that it takes almost a full second for the computer to show commanding PE?
Also minor but wanted to ask....at idle my rpms sway a couple hundred rpm. How can I fix this?
Log and tune attached.
2006 GTO A4
LS3 427
Originally Posted by 0-60n3
you command what you want in the PE table
then you use the AFR error PID(in conjunction with AFR Commanded and your AFR reported by your wideband) and use the end result to change your MAF and VE tables (Multiply by % - Half)
if the results come out jagged, do some smoothing(by hand or using the auto smooth buttons) and repeat the process till you can get the results closer and smoother
-Scott -
Did you look at my logs and the tune? It seems to me that the STFTs are where they need to be. But for whatever reason my wideband shows the car is rich until 6,000 rpms and higher.
2006 GTO A4
LS3 427
The fuel trims are only for non-PE. When you go into PE you're hitting different areas of the MAF curve (or VE table). Like Scott said you need to put the car into open loop (no fuel trims) and tune the VE and/or MAF tables using the AFR Error.
In looking at your log you are logging WAY WAY too many PIDs. Look at the help file to see how the number of PIDs defined in the table affect your frame rate. You need to create different configs to do different things. One for open loop tuning, another for fuel trim tuning, another for idle, another for tranny tuning. Each one should only have the PIDs necessary to do whatever it is you're tuning at the time.
Look for threads by me with "towel" in the subject for a gen 4 idle tuning procedure (and config).
Bill Winters
Former owner/builder/tuner of the FarmVette
Out of the LSx tuning game
You can check the tune I posted but LTFT and VE are disabled I believe. So what exactly needs to be tuned....the high MAF table? I logged the first few cells in the high maf table and they were ~-17. I adjusted those but I have to get A LOT of speed to get to the other cells. I could try just copy/paste special -17 for the rest of the cells but wasn't sure if that is approaching it correctly. The PE table is set to 12.88 across the board. I'm just trying to get commanded to match actual on my WB.
2006 GTO A4
LS3 427
i had the same issue. if my commanded was 12.75afr and the wideband was 11.7 I then modified the maf high in those HZ areas by multiplying those cells by .925... that is how i got my commanded to match my actual closely. I dont know how to tune via the ve table. maybe someone can chime in??? im a newbie but it looks like u go into pe at frame 74 at 56 tps... it was in pe before you fully floored it... maybe im wrong but thats what it looks like to me. another thing... the last cell in ur maf low HAS to match the first cell in you maf hi
Last edited by stanger383; 05-20-2010 at 04:38 PM.
So you're saying I probably need to tune the maf high table? That's what I was thinking I just don't know how to do it without doing 140 up and down the hwy. I have a 100mm maf so I have to get into the power to get the hz to go up. I don't know how to tune the VE table either but mine has always been disabled.
I didn't know the last cell had to match the first cell in the two tables. Hmm.
Good info man. If you have anymore I'm open ears.
2006 GTO A4
LS3 427
the maf hi table can be tuned using 1st or 2nd gear. I logged maf HZ .. they seem to be related to rpm and load( they are air going into the engine as far as i know) and yes the last cell in maf low MUST match first cell in maf hi( after all its the same hz value. here is a link to whats happening with my tune right now. I bet it will respond better just changing those few things
http://www.hptuners.com/forum/showthread.php?t=29539
the maf hi table can be tuned using 1st or 2nd gear. I logged maf HZ .. they seem to be related to rpm and load( they are air going into the engine as far as i know) and yes the last cell in maf low MUST match first cell in maf hi (after all its the same hz value. here is a link to whats happening with my tune right now. I bet it will respond better just changing those few things
http://www.hptuners.com/forum/showthread.php?t=29539
MAF HZ are based on airflow and air density
air moves passed the wires in the MAF..and cools it down...
the pcm increases the MAF frequency to reheat up the wires to keep them at a set temperature/resistance
the values you are plugging into the MAF tables are to tell the PCM what the mass of the Air actually is...very much like you do the VE table...only its a slightly differnt type of value... typically you will get the highest MAF Hz at the highest speeds at WOT...
you can make a guestimate at the trend of the data in the upper half beyond what you can actually log
another way to get a higher reading is to get some colder and more dense air in there
-Scott -
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