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EEC Tuner tuning notes

Most of the information in this file is directed specifically at the A9L processor. However, the information is still applicable to the other processors in theory and description of operation.

This is a work in progress. Comments are welcomed and appreciated.


Think of this as a rev limiter using the following formula:

PIP = 6006250/maxRPM maxRPM = 6006250/PIP for example stock A9L PIP= 961 maxRPM = 6006250/961 = 6250 rpms Lower numbers give a higher rev limit.

The PIP is a sample rate frequency that limits the PCM program operating loop to a minimum rate. If the loop is sampled less then PIP times within one operating cycle (2 crankshaft revolutions), the PCM limits rpm.

With this logic, you should be able to set the pip to 1 and the car should run normally, but not limit RPM. I have tested this on an A9L processor.


The WOT_VOLTAGE defines the throttle position that WOT operating mode is entered. On A9L processors, the WOT_VOLTAGE is the measured TPS voltage minus the idle voltage. That makes

the stock 2.71 volts really

~3.71 volts as read on the TPS signal line. TPS usually goes to 4.6V

at full scale. So stock WOT operation is triggered at about 80% and up throttle. You can control when the WOT functions and scalars are used by adjusting this value.

The following tags are only active during WOT operating mode WOT_SPARK_ADDEER WOT_ADVANCE_VS_RPM W O T _ F U E L _ M U L T I P L I E R _ V S _ R P WOT_ADVANCE_VS_ECT WOT_ADVANCE_VS_ACT M

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