Hondata S300 DIY Wide Band O2 Sensor Install & Wiring

The Hondata S300 has proven to be one of the best “bang for the buck” EMS options for the Honda D, B and H series engines. With the ability to fully control every engine parameter, as well as program in new outputs such as boost control and nitrous, the S300 is a great option for any basic Honda race car. In this article we will run you through the Brewed Motorsports preferred method of hooking up a wide band oxygen sensor aka WB O2 or air fuel ratio gauge / monitor.

1. We highly recommend using the AEM X series AFR gauge for the most accurate AFR/Lambda data. Install your wide band O2 kit per the supplied install instructions. 
2. Find the 0-5 volt signal wire (this is what we will be connecting to the S300)
3. Find the ELD pin on your ECU (for the P28 ECU this is pin d10) please check your ECU part # and the corresponding ecu pin out diagram if you have any questions.
4. Verify your WB O2 sensor is working correctly (this should be described in the WB O2 manufactures instructions)
5. Find the output voltages versus Lambda graph for you particular WB (this will be in the install or supplied specifications included with your WB)
6. Connect the 0-5v WB o2 signal wire to the ELD pin on your ECU
7. Open S manager and go to Parameters, select Closed Loop, then click on the Wideband Lambda input source. Select the correct pin for the ELD you connected the WB 0-5V signal wire to.
8. Under the “Voltage / Lambda conversion table” enter the values you found in step 5
9. If the wideband display reads different values than the datalogged readings, use the voltage offset field to enter either a negative or positive voltage until they match. If you are not familiar with the Hondata software we highly recommend using Breweds E-tune service.

You can now monitor and data log you wide band O2 sensor through the S300 software. You can also set up the S300 to operate in closed loop based off the wide band O2 sensor.

Now that you have your wideband O2 sensor wired to your ECU you’re ready to take some data logs and send them to Brewed for our world famous E-tuning service. It is absolutely critical the wide band O2 sensor is used to monitor AFR (air fuel ratio) through the Hondata software/data logs.

Honda ECU packages:

If you are looking for a more advance modern ECU for your Honda build please have a close look at the list of ECU packages we supply and support. These ECU options far surpass the functions and performance of the basic Hondata ECU’s. 

• Motec M130 M1 series ECU’s offer top level features & performance for all types of motorsports from land to sea.
• Haltech Elite 2500 Budget friendly ECU with user friendly setup and software.
• AEM Infinity 506 Advance ECU functions with great price point. Perfect for any budget orientated race car looking for maximum tune-ability.
• Emtron ECU KV series ECU’s offer advance functions features and configuration options perfect for modern cars/engines used in Motorsports.