TwinTurbo.NET: Nissan 300ZX forum - Yes, there is a ROM table to control Idle timing
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Subject Yes, there is a ROM table to control Idle timing
     
Posted by zromtech on March 03, 2013 at 8:39 PM
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In Reply To Has anyone found the ECU code controlling the On Idle Timing posted by Gordo 93TT Daytona on March 01, 2013 at 10:02 PM
     
Message There is a 16-byte table at ROM location 0xF520 that controls the timing used during idle. It is indexed via RPM / 200 and contains the desired idle timing value + 128.

The OEM table (in hex):
$8F, $8F, $8F, $8F, $8F, $8F, $8F, $8F, $8F, $8F, $94, $94, $94, $94, $94, $94

(in decimal):
143, 143, 143, 143, 143, 143, 143, 143, 143, 143, 148, 148, 148, 148, 148, 148

subtracting 128 results in actual timing values:
15, 15, 15 ,15, 15, 15, 15, 15, 15, 15, 20, 20, 20, 20, 20, 20

So, like you observed, the Idle On timing transitions from 20 to 15 degrees right at 2000RPM.


Can anyone confirm if Zem/Nistune let you modify this table?


     
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