STFT Enabled?
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Teching In
Joined: Mar 2017
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STFT Enabled? I'm new to HPtuners, but I'm am reading everything I can.....but all tuning instruction point to Disabling both STFT and LTFT when tuning. I have had a guy tune my car and I have a wide band, we have decided to run open loop and only use VE table and zero'd the Maf freq table.
To Learn more about the changes he has made I downloaded a stock original tune for the car and I'm using the compare feature to see the changes he has made, BUT...why does the stock tune show STFT disabled? I thought both short and long term had to be Enabled? Can someone please explain this to me?
Every tuning instruction says to disable them, but this one is already disabled?
I thought it needed it enabled to use both? Does it only read the one?
Perplexed.
To Learn more about the changes he has made I downloaded a stock original tune for the car and I'm using the compare feature to see the changes he has made, BUT...why does the stock tune show STFT disabled? I thought both short and long term had to be Enabled? Can someone please explain this to me?
Every tuning instruction says to disable them, but this one is already disabled?
I thought it needed it enabled to use both? Does it only read the one?
Perplexed.
10 Second Club
Joined: Nov 2005
Posts: 933
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What kind of car and year----was it tuned before? Maybe somebody left STFT's off by mistake ?
There is more than one way to skin a cat. I don't use LTFT's or a MAF.
If it is a "stock" GM tune, I believe both ST and LT should be used.
There is more than one way to skin a cat. I don't use LTFT's or a MAF.
If it is a "stock" GM tune, I believe both ST and LT should be used.
Some calibrations will have a setting for STFT enabled or disabled in open loop. That only effects open loop. If that is set to disabled, when those vehicles enter closed loop the STFTs become enabled and active. If you are running open loop like you say you won't be able to use fuel trims anyway. You have to have O2 feedback in closed loop for fuel trimming.
Thread Starter
Teching In
Joined: Mar 2017
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Very good explanation, I understand why my tune would have STFT disabled
so I just wanted to confirm it against a stock factory tune, but found factory tune has same? I was sure that it would be enabled?
so are you saying in some cases this is normal? For factory tune to have STFT disabled? I guess so if I have have looked at two now that are.
so I just wanted to confirm it against a stock factory tune, but found factory tune has same? I was sure that it would be enabled?
so are you saying in some cases this is normal? For factory tune to have STFT disabled? I guess so if I have have looked at two now that are.
To simplify this-- If you are running in open loop, you would normally have no fuel trims. However, the pcm has the option of allowing STFT in what is otherwise open loop. This means that the computer will still make some corrections, but the corrections will not be stored as they would for LTFT. Since the factory style tune goes into closed loop as soon as is reasonably possible, there is no reason for a stock tune to have this feature enabled.
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When I had long tubes I ran with full time open loop,
STFT enabled because LTFTs would creep too much
from false trimming (cold sensors). At least STFTs
reset every time you enter the trim cell.
STFT enabled because LTFTs would creep too much
from false trimming (cold sensors). At least STFTs
reset every time you enter the trim cell.
Thread Starter
Teching In
Joined: Mar 2017
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Thanks Jimmy, yes I have long tubes as well
my tuner guy said it's open loop with speed density. I see the WOT air fuel looks good on the scan but the rest is a bit lean so I will fatten it up and give it a whirl, cold and wet here still so not many dry days to get out and play. My goal is to get this 3100 lb'er into the 11's. I'm gonna hit it with a 150 shot so I'm looking for one of those lingerfield LNC-2000 two step timing boxes to pull a couple degrees and not hurt things.
my tuner guy said it's open loop with speed density. I see the WOT air fuel looks good on the scan but the rest is a bit lean so I will fatten it up and give it a whirl, cold and wet here still so not many dry days to get out and play. My goal is to get this 3100 lb'er into the 11's. I'm gonna hit it with a 150 shot so I'm looking for one of those lingerfield LNC-2000 two step timing boxes to pull a couple degrees and not hurt things.
