This is a question for older systems that use only one O2 sensor:

Since voltage remains the same in a parallel circuit, what would be the effect(s) of splitting the signal and running two sensors?

 

Why? I'd go the other way, one sensor to two inputs on say a mass air conversion, but I'm not sure the reason to run dual O2 sensors with only one input.

 

I was thinking more along the lines of an early SD EEC-IV system with longtube headers - running one sensor into each collector.

I was wondering what the possible effects of that might be.

Your idea of running one sensor into to inputs, on an MAF system, is interesting. EC logic tells me if that would work, the inverse would work also. But there's also the mechanical aspect, and other possible variables, and I haven't given it much thought. I'm curious what some of the wrench-heads here would have to say about such a thing.

 

I don't think this is necessarily true. If you put a 6 volt battery in parallel with a 12 volt battery, the 12 volt battery will send current into the 6 volt battery till they equalize(probably blow up before that happens).

You can think of an oxygen sensor as a very small battery, so if one sensor read high, and the other read low, I think the sum of the voltages will be something totally different, giving the computer no real info that it can use.

Most of the early EECIV v8 applications did have two oxygen sensors.

 

Franklin2,

You're right. I hadn't thought about the behavior of the signal return until today, and it didn't even take much to figure out the problems associated with such an idea - which are exactly what you described. I also posted this in the exhaust forum, and Bear River posted a response with the same conclusions that you gave.

I appreciate your taking the time to reply. Thanks.

 

Don't mean to hijack here, just want to learn something.
So, the oxygen sensors are a voltage "generator" of sorts? Like a thermocouple?
I would have thought they were a variable resistor or current limiting device of some sort.
Can you Confirm please.
Thanks, Rob.

 

I will give you the technical explanation out of a fuel injection book I have;

The EGO sensor is an electrochemical device consisting of two layers of platinum separated by a layer of zirconium oxide. The one plate is exposed to ambient oxygen, while the other is exposed to the oxygen content of the exhaust system. Although an electronics engineer would probably disagree, these layers are a lot like the plates in a battery separated by an insulator.

The EGO sensor is installed in the exhaust system, usually close to the manifold. When the engine is started, the hot exhaust gases passing through the manifold begin to heat the EGO sensor. When the temperature of the EGO sensor reaches 600 degrees F, the EGO sensor becomes conductive for oxygen ions. In the same way that the plates of a battery begin to attract electrons from the electrolyte to create a voltage, the warm EGO sensor attracts oxygen electrons. If the number of oxygen electrons on the exhaust side is equal to the number on the ambient air side, then the electrons equalize and no voltage is produced. As the oxygen content of the exhaust decreases, an inbalance occurs and the EGO sensor begins to produce a voltage.

To summarize: A cold EGO sensor will produce no signal; as the sensor warms up, it will begin to produce a voltage. A lean exhaust condition--one with a high oxygen content--will produce a voltage less than 450 millivolts, and a rich exhaust condition will produce a voltage greater than 450 millivolts.

copied from "How to Tune and Modify Ford Fuel Injection" by Ben Watson

 

Thank you Dave, Great reply.