WOT tuning woes?
#1
TECH Junkie
Thread Starter
iTrader: (3)
Join Date: Nov 2001
Location: TEXASS
Posts: 3,202
Likes: 0
Received 0 Likes
on
0 Posts
WOT tuning woes?
Ive already tried to dial in the VE table using the autove with Lc1. My commanded AFR and LC1 are spot on each other everywhere even WOT when I reenable the MAF. LTFTs look good all over the board between +5 and 0 at idle and hover between 0 and 5 throughout cruising. Problem is when I go WOT the computer starts off with a commanded AFR around 14.2 then steps on down until at 6000 rpms it is 11.7 and actually gets to 11.5 or lower by the time 6800 rpm comes around. Ive tried playing with the PE vs RPM and this has absolutely NO EFFECT on commanded AFR, it does exactly the same thing everytime. Ive also changed the commanded AFR vs MAP table for grins and it also had no effect?? I then tweaked the MAF and that simply made my commanded AFR and LC1 disagree at WOT. How do I make the computer command what I want it to command at WOT? Is it possible my VE table is off at 100kpa MAP? What makes the PCM want to add so much fuel at WOT? Id like to get this thing where i can simply adjust WOT throttle fuel by the PE vs RPM multiplier.....
#5
TECH Senior Member
iTrader: (23)
Join Date: Aug 2005
Location: Watertown, NY
Posts: 8,797
Likes: 0
Received 0 Likes
on
0 Posts
Your commanded AFR is what you set in the PE table, your actual WOT AFR depends on how accurate your MAF and VE tables are. Since your LTFt's are positive, that extra fuel is being dumped in at WOT. What you want to do is get the LTFT's between zero and -5. That way no extra fuel will be added on top of what is usually added at WOT.
When the MAF is plugged in and you are at WOT fueling is based on MAF solely. So if your AFR is off then fine tune the MAF after you get the LTFT's beloe zero. What I did was log the maf ferquency and AFR all through a WOT run. Then match the AFR to the corresponding MAF frequency in time and adjust the MAF value by the percentage by which the AFR is off from commanded.
Example: If Stoich is set at 14.7 and your PE table is set to 1.2 all acroos the board that makes commanded AFR 12.25. Now lets say you log and at 4000RPM's you are at 11.5 AFR. You then determine the percentage of how much the actual AFR is off from commanded. This is calculated by commanded/actual = 12.25/11.5 = 106.5 %. You then will go to the MAF table and adjust the cell for 4000RPM's and increase the value by 106.5%. This is how I did it and my AFR is dead on what I command
There may be a easier way to do this in EVILive, I use LS1 Edit so I gotta do it the hard way.
When the MAF is plugged in and you are at WOT fueling is based on MAF solely. So if your AFR is off then fine tune the MAF after you get the LTFT's beloe zero. What I did was log the maf ferquency and AFR all through a WOT run. Then match the AFR to the corresponding MAF frequency in time and adjust the MAF value by the percentage by which the AFR is off from commanded.
Example: If Stoich is set at 14.7 and your PE table is set to 1.2 all acroos the board that makes commanded AFR 12.25. Now lets say you log and at 4000RPM's you are at 11.5 AFR. You then determine the percentage of how much the actual AFR is off from commanded. This is calculated by commanded/actual = 12.25/11.5 = 106.5 %. You then will go to the MAF table and adjust the cell for 4000RPM's and increase the value by 106.5%. This is how I did it and my AFR is dead on what I command
There may be a easier way to do this in EVILive, I use LS1 Edit so I gotta do it the hard way.
Last edited by brad8266; 04-20-2006 at 07:41 PM.
#6
TECH Junkie
Thread Starter
iTrader: (3)
Join Date: Nov 2001
Location: TEXASS
Posts: 3,202
Likes: 0
Received 0 Likes
on
0 Posts
Thats great but the AFR and LC1 are right on top of each other...They agree. The computer is calling for 11.5/1 and it is getting it. Ill assume that means my VE table and MAF tables are correct. As I said I changed the MAF table and this simply made the commanded and actual LC1 measured values disagree so I put it back like I had it. Thats not the problem. Also adjusting the PE vs RPM table or the open loop commanded fuel does absolutely nothing to my WOT mixture. The PCM continues to call for around 14.0 on tip in to WOT at 2500 rpm then progressively steps down about .5/step....By 6800 rpms Its calling for 11.5 or so....The LC1 is agreeing and follows the steps down spot on.....
Trending Topics
#8
TECH Junkie
Thread Starter
iTrader: (3)
Join Date: Nov 2001
Location: TEXASS
Posts: 3,202
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by brad8266
Is COT on?
#9
TECH Senior Member
iTrader: (23)
Join Date: Aug 2005
Location: Watertown, NY
Posts: 8,797
Likes: 0
Received 0 Likes
on
0 Posts
if its set to 1 that should put you at 14.7 at WOT. yeah disable that COT crap and see how it works. Keep in mind you really should get your fuel trims negative rather than positive, the positive trims will make the PCM add even more fuel at WOT. You might want to completey retune closed loop to get it negative before you go any farther. if your the fuel cell you are in right before WOT is +4 then the PCM will add 4% more fuel than is called for at WOT, so it will make you rich.
#10
TECH Junkie
Thread Starter
iTrader: (3)
Join Date: Nov 2001
Location: TEXASS
Posts: 3,202
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by brad8266
if its set to 1 that should put you at 14.7 at WOT. yeah disable that COT crap and see how it works. Keep in mind you really should get your fuel trims negative rather than positive, the positive trims will make the PCM add even more fuel at WOT. You might want to completey retune closed loop to get it negative before you go any farther. if your the fuel cell you are in right before WOT is +4 then the PCM will add 4% more fuel than is called for at WOT, so it will make you rich.
#11
FormerVendor
iTrader: (9)
Join Date: May 2003
Location: Jacksonville, Fl
Posts: 1,573
Likes: 0
Received 0 Likes
on
0 Posts
Just a stupid question but, you used Autotune to do the VE table correct? Autotune has you put the whole 3605 Commanded open loop fuel table to to stoich, 14.63 or "1". You did put the 3605 table back after the autotune? I only mention this because I never, ever have forgot to change it back.
If you logged commanded vs. lc-1 actual, which it sounds like you have as described it would comand rich and your lc-1 is saying yep I'm rich, now what.
If you logged commanded vs. lc-1 actual, which it sounds like you have as described it would comand rich and your lc-1 is saying yep I'm rich, now what.
#12
TECH Junkie
Thread Starter
iTrader: (3)
Join Date: Nov 2001
Location: TEXASS
Posts: 3,202
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Doc
Just a stupid question but, you used Autotune to do the VE table correct?
If you logged commanded vs. lc-1 actual, which it sounds like you have as described it would comand rich and your lc-1 is saying yep I'm rich, now what.
If you logged commanded vs. lc-1 actual, which it sounds like you have as described it would comand rich and your lc-1 is saying yep I'm rich, now what.
Yeah the Lc1 is agreeing with commanded.
#14
TECH Addict
iTrader: (10)
Join Date: Jun 2004
Location: Commerce Twp, MI
Posts: 2,918
Likes: 0
Received 0 Likes
on
0 Posts
If COT is on, it will add fuel after a few seconds of WOT. It usually hit my car around 3rd gear. Turn it off and you should see the commanded AFR reflect the PE and Fueling in Open Loop tables.
#15
TECH Junkie
Thread Starter
iTrader: (3)
Join Date: Nov 2001
Location: TEXASS
Posts: 3,202
Likes: 0
Received 0 Likes
on
0 Posts
Guys you were exactly right! The cat overtemp protection was the problem! Disabled it and now the PE vs RPM works perfectly! I think Im done with my tune.
The cat overtemp has its OWN set of commanded fuel numbers and eventually ends up at 11.7 AFR no matter your PE settings!
Thanks!
The cat overtemp has its OWN set of commanded fuel numbers and eventually ends up at 11.7 AFR no matter your PE settings!
Thanks!
#16
TECH Senior Member
iTrader: (23)
Join Date: Aug 2005
Location: Watertown, NY
Posts: 8,797
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by cantdrv65
Guys you were exactly right! The cat overtemp protection was the problem! Disabled it and now the PE vs RPM works perfectly! I think Im done with my tune.
The cat overtemp has its OWN set of commanded fuel numbers and eventually ends up at 11.7 AFR no matter your PE settings!
Thanks!
The cat overtemp has its OWN set of commanded fuel numbers and eventually ends up at 11.7 AFR no matter your PE settings!
Thanks!
#17
12 Second Club
iTrader: (1)
Join Date: May 2005
Location: Bradenton, FL
Posts: 684
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by muncie21
Have you checked OLFA? I believe at WOT the PCM will take the richer of the two (PE or OLFA).
My stock OLFT table is 1.13 at WOT, so anything below that for PE doesn't make a difference.
#18
TECH Junkie
Thread Starter
iTrader: (3)
Join Date: Nov 2001
Location: TEXASS
Posts: 3,202
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by silverTA2002
Exactly. If you put PE to 1.0 and your Open Loop F/A table calls for 1.13, you'll get 1.13 fueling.
My stock OLFT table is 1.13 at WOT, so anything below that for PE doesn't make a difference.
My stock OLFT table is 1.13 at WOT, so anything below that for PE doesn't make a difference.
#19
Launching!
Join Date: Aug 2002
Location: Ontario, Canada
Posts: 231
Likes: 0
Received 0 Likes
on
0 Posts
Yep. COT is a bugger. I had the same issues while tuning with the wideband a couple nights ago. Kept trying to make the PE do something, it didn't. Then after we switched off COT bam we were sitting pretty at 12.9:1. Maybe a touch too lean at WOT right now but I can fuddle with that later.
Also, to note, we set the PE to 1.13 (commanding 13:0x:1 AFR) and then simply scaled down the MAF airflow readings for the given frequency range to get my target AFR.
Also, to note, we set the PE to 1.13 (commanding 13:0x:1 AFR) and then simply scaled down the MAF airflow readings for the given frequency range to get my target AFR.
#20
On The Tree
iTrader: (1)
Join Date: Sep 2005
Location: Texas
Posts: 156
Likes: 0
Received 0 Likes
on
0 Posts
I am having the same problems trying to tune with a wideband. It didn't matter what I set the PE values to be, it always ran 12.0:1 AFR and the car ran the same ET/mph. This is with a stock cam and stock program.
Does this COT thing matter if I have no catalytic converters? And yes, I am an HP Tuners newbie.
Does this COT thing matter if I have no catalytic converters? And yes, I am an HP Tuners newbie.