Tuning VE Before LTFTs Have Been Learned
09-02-2005 | 01:53 PM
#1
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From: West Lafayette, IN
Tuning VE Before LTFTs Have Been Learned Hey Guys,
I've been working on my VE table for the past few days but fear I may have been doing it incorrectly. I've unplugged the MAF, reset the fuel trims, and enabled fuel trim learning. After each of several 20-30 minute drives, I've taken the LTFT value, added the STFT value and then added half of the sum to the corresponding cell in the VE table.
I just learned, though, that the LTFTs are not considered learned until the STFTs are near 0. In my case, each time I've altered the VE table I've had several instances of STFTs greater than 10, and some even greater than 20.
What steps should I take to correct this error? Should I reflash the PCM with the VE table I began with and wait for all of the LTFTs to be learned then start over?
And as an aside, for this process do the fuel trims need to be reset each time the car is started? Or can I simply reset the fuel trims and enable fuel trim learning once and do the appropriate driving over the course of several days?
Thanks Much,
Josh
I've been working on my VE table for the past few days but fear I may have been doing it incorrectly. I've unplugged the MAF, reset the fuel trims, and enabled fuel trim learning. After each of several 20-30 minute drives, I've taken the LTFT value, added the STFT value and then added half of the sum to the corresponding cell in the VE table.
I just learned, though, that the LTFTs are not considered learned until the STFTs are near 0. In my case, each time I've altered the VE table I've had several instances of STFTs greater than 10, and some even greater than 20.
What steps should I take to correct this error? Should I reflash the PCM with the VE table I began with and wait for all of the LTFTs to be learned then start over?
And as an aside, for this process do the fuel trims need to be reset each time the car is started? Or can I simply reset the fuel trims and enable fuel trim learning once and do the appropriate driving over the course of several days?
Thanks Much,
Josh
09-02-2005 | 02:30 PM
#2
disable the ltft's and tune using only a good average on the stft it will help narrow down the lt's once you re-enable them I did a write up on it
hope it helps http://www.performancetrucks.net/for...9&page=1&pp=10
you dont need to reflash the stock ve table it would just take forever with the method your using. If your say you used a trim value of +2 when in actuality the learned value would have been +4 you are going in the right direction just takes time.
fuel trims need to be reset every time you adjust the ve or maf tables
hope it helps http://www.performancetrucks.net/for...9&page=1&pp=10
you dont need to reflash the stock ve table it would just take forever with the method your using. If your say you used a trim value of +2 when in actuality the learned value would have been +4 you are going in the right direction just takes time.
fuel trims need to be reset every time you adjust the ve or maf tables