Specializing in 1980-1981 Turbocharged 4.9 (301) Pontiac Trans Ams and Firebird Formulas.​


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specify 1980 or 1981 w/CCC when ordering

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ESC By Pass Board

The 1980 and 1981 Turbo 4.9 Trans Ams and Formulas came equipped with Electronic Spark Control.  The ESC  module monitored engine detonation with a knock sensor placed on the engine.  When detonation was detected, the ESC module retarded the ignition timing until detonation was no longer heard, then regular ignition timing was allowed to return.

A somewhat common occurrence is for a Turbo 4.9 to experience a no start condition due to no ignition spark.  One of the causes can be from a bad ESC module.  This module can be "by passed" using our custom made by pass boards.  Simply unplug the faulty ESC module and insert the board into the electrical connector.  This allows the ignition to function like a standard GM HEI distributor.  This board also allows the ignition timing advance to work correctly on the 1981 Turbo 4.9's with Computer Command Control (CCC) and will not cause the Check Engine Light to illuminate.

Note: After installing the by pass board, you will no longer have detonation protection.  The ESC system will be inoperable.  Make sure to always use the highest octane fuel available and listen for detonation or knock when driving your 4.9 Turbo.