drop voltage from 5v to 1v

ok i have a small problem, im sure you guys have the solution

i have a 3000gt, twin turbo, with 2 factory o2 sensors. the factory o2 sensors normally output 0v-1v signal to the ecu. the car is highly modified and i do not have plug ins for the factory o2 sensor locations. i have an aftermarket wideband o2 sensor, which i have tuned the car with. the wideband o2 sensor has a output wire to the ecu, but the range is 0v-5v. i need to lower the voltage to what the ecu can handle.

simplified description:

i have 0v-5v signal, i need to lower it to 0v-1v


with some research i found a formula:

V * ( R1 /(R1 + R2) )

i plugged in 5 in V, 680 in R1 and 170 in R2

via excel spreadsheet, it gives me a perfect range, but someone told me i cant just do that? i also am in the dark about how to wire it.

i have a solder iron, took a few classes in college on dc electronics, but it was so long ago. im ok wiring a circuit.

You resistors are correct (they merely need to be a 1:5 ratio), but as stated, you probably can't do that.

O2 sensors are VERY sensitive - eg, test one with a multimeter and you blow the sensor (at least if testing resistance).

You'll need to get the specs on your sensor and make a buffer circuit.
Yours sounds like a wideband.
Traditional narrowband sensors were limited to currents below 1uA hence requiring buffers with (say) 10M impedance.
I think widebands are much the same.
You might be able to use (say) 2M & 12M resistors etc, but I'd use a buffer.


PS - there is also the ECU. ECUs for narrowband sensors are often akin to a bang-bang reaction/controller whereas for widebands they can take a more proportional response. And sensor delays must also be factored in. However, if you say you have tuned the ECU for the wideband sensors...

You cannot just use resistors to drop the voltage. Narrowband sensors read lean when voltage is low and rich when voltage is high. Whereas wideband sensors read lean when voltage is high and rich when voltage is low. Besides that narrowband sensor signals are not linear like wideband sensors.
Aftermarket wideband sensor controllers can usually be set to output a wideband or narrowband signal. What controller are you using?

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This information is provided only as a reference.
All circuits should be verified with a digital multi-meter prior to making any connections.

I am using an AEM UEGO. its a high quality 0-5v wideband with digital gauge. my car harness has 2 narrowband o2 sensor connectors that run to the ecu. the wideband has a 0-5v output, but the ecu is expecting a 0-1v input.


i overcame this issue by purchasing a flash ecu, which has a modified circuit that expects a 5v input rather than 1v for the ecu.

thanks!

The 5V input on the flash ECU is not for closed loop operation. It is used for datalogging with EvoScan.
Do you have the AEM 30-4100? If you do, you can set the white wire to output a 1v signal that can be used in place of the stock narrowband. You will need to set it to position P4 for narrowband output.

-------------
This information is provided only as a reference.
All circuits should be verified with a digital multi-meter prior to making any connections.