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TOPIC: ECU Calibration Question...

ECU Calibration Question... 03 Jun 2013 23:10 #1

  • GM Tim
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Had a great question thrown at me today.

Yesterday I caped the Crank vent to the TB on my 01 Silverado 4.8 (already capped the PCV 2 weeks ago) and put in some new $3 Bosch platinum plugs gaped at (.072 = +20%) I am experimenting.

When I first started it up, the motor lugged and ran rough. After a few seconds I shut it off and restarted it. That time it fired right up and idled down just fine.

NOW- If the ECU can adjust in seconds to capped vacuum ports and over gaped plugs...

Why does it take a whole month of driving or more for the ECU to adjust to the groove?

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ECU Calibration Question... 04 Jun 2013 10:53 #2

  • Tracy Gallaway
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My guess, it was adapting to open loop starting cond. It was re-setting the IAC, that's pretty simple for it. Fuel trims take longer, w/ adaptive learning, the short trims and other inputs shift the Long trims over time.

My 2 cents.

Tracy G
Tracy Gallaway
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Gadgetman Reno, NV
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