_nameless
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« Reply #17 on: December 07, 2022, 11:28:27 AM »
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There are many ways to tune dead times. One that I use most is set fkkvs all to 1's and use dead times of injectors that are close, since those saab injectors are really close to normal vag injectors; I would use the dead times from a 180 or 225 as a starting point. Then calculate krkte theoretical value, and flash the car with the starting calibrations that you have made. Then wait for the car to go into a closed loop, start doing some mixed driving, log long term fuel trims and adjust accordingly. Normally I start with the long term fuel trims at idle, if the ecu is adding fuel to idle ltft’s then it is normally a safe assumption (providing your theoretical krkte value is close to target) that you need more injector on time in tvub between the 12 and 14 volt cells. When tuning tvub you really only need to focus on the 12-14v cells as that's normal system operating voltage. You will need to make a few edits, and shoot for as close to zero as possible, 2% is a good goal. Krkte more or less would reflect your long term fuel trims at part / full throttle and the same theory applies for adjusting that. Once you have krkte within 5% you can go back to fkkvs and run through that. This works good for me and is normally my goto method for calculating tvub for injectors with unknown dead times. Also, I have seen less favorable results with more convoluted methods. Just my 2c, do with it what you will.
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« Last Edit: December 07, 2022, 11:36:28 AM by _nameless »
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Giving your mom a tuneup
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