Approval Details

Valid E.O.


This Executive Order approved the specified parts on on October 8, 1991.
As of Monday, April 15th, 2024 this Executive Order has not been overturned or superceeded.

Approved Parts

Part NumberModelsModification
WI-TEC-721989-1991 Chevrolet and GMC 1/2 and 3/4 ton light-duty trucks with a 350 CID fuel injected engineSpark timing is retarded up to 5 degrees to prevent detonation

This Executive Order may be listed as:
  • C.A.R.B.E.O. D-231
  • Executive Order 231 / D231
  • ARB # D-231
  • Executive Order No: D-231
  • C.A.R.B. No. D-231
  • Resolution D-231
For Free CARB Executive Order Status verification, email an image of the device Executive Order label as well as the Year/Make/Model and Test Group # of the vehicle to [email protected]

Download: Executive Order D-231 PDF

D-231 Document:

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