Reading Long term fuel trims
01-20-2016, 10:14 PM
#1
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Car: '86 Trans Am
Engine: 355 TPI
Transmission: 700r4
Axle/Gears: 3.27
Reading Long term fuel trims
After installing a custom tuned chip and having cold start issues, my tuner told me that he needs see the long term fuel trim data so he see what adjustments are being made so he can adjust the injector settings. How can I read this data? Can I use an OBD1 scanner?
01-21-2016, 06:20 PM
#2
Re: Reading Long term fuel trims
Yeah, what he's asking for are the BLM's or Block Learn Values. But you'll need to drive around for a while to get the fuel trims established at the various operating conditions. The fueling is based on load and rpm and there's a cell with a fueling value in it for each load and rpm value. You'll want to hit as many combinations of load and RPM as possible during a datalog (i.e., low rpm and high load, mid range rpm, low load, high rpm light load, etc)... The more data he has on your fuel trims, the less iteration should be expected.
01-21-2016, 08:46 PM
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Car: '86 Trans Am
Engine: 355 TPI
Transmission: 700r4
Axle/Gears: 3.27
Re: Reading Long term fuel trims
Yeah, what he's asking for are the BLM's or Block Learn Values. But you'll need to drive around for a while to get the fuel trims established at the various operating conditions. The fueling is based on load and rpm and there's a cell with a fueling value in it for each load and rpm value. You'll want to hit as many combinations of load and RPM as possible during a datalog (i.e., low rpm and high load, mid range rpm, low load, high rpm light load, etc)... The more data he has on your fuel trims, the less iteration should be expected.
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