O2 Delay Timer

Wideband O2 (WBO2) sensors provide the ECU current exhaust Air Fuel ratio which is used in tuning and correction.  These units provide much more precision than a narrowband and or are recommended for all Brown EFI products.   If the WBO2 sensor is exposed to exhaust system moisture after heating, the sensor experiences thermal cracking and destroys the sensor.

The Brown O2 delay timer is designed with 2 purposes in mind:

  • Delay the heating of the O2 to prevent thermal shock caused by moisture in the exhaust during cold starts
  • Prevent accidental RPM indication/injector firing during a switch on, not running condition due to high current noise

The O2 Controller is powered by the fuel pump circuit which should only supply power during the 5 sec switch-on and while the engine is running.  Under certain conditions combined with the O2 sensor heating, the ECU interprets this noise as RPMs and allows the fuel injectors to fire.  This can flood the system and hydrolock, filling of the engine with fuel if the system is left unattended.

The delay timer is RECOMMENDED for systems with a crank trigger wheel and REQUIRED systems with a VR-triggered distributor (Brown EFI Distributor).  We will provide these at a low cost for current Brown EFI system owners.