PDA

View Full Version : 3 Oxygen Sensors



SmoothieV
07-02-2008, 01:49 PM
First I just wanted to thank everyone for being so helpful. These forums are a lot of times more important than the guide books themselves!

Ok, so I drive a 2004 Mazda3 sHatchback 4cyl. 2.3L. It has 3 O2 Sensors, front, middle and rear. Does this mean I need 3 EFIE's? If not, which should I be putting it on?

s_barrett
07-03-2008, 12:29 AM
i should think the the output from one could be split three ways, one for each sensor, using diodes; but would need to compensate for the 0.7 volt diode drop. not sure though.
note that these sensors really measure hydrocarbons, not oxygen, a misnomer and deliberate stumbling block introduced by the oil industry.

ELECTR0N3RD
07-03-2008, 03:16 AM
I read somewher that you can actually just wrap the o2 sensors in several layers of aluminum foil, I havent yet tried this but is it true?

h-power
07-04-2008, 04:59 PM
Most early O2 sensors were placed upstream of the catalytic converter. Later a second sensor was placed downstream of the cat to measure cat efficiency. The only O2 you need to worry about is the one that is upstream. If you have one at each exhaust manifold and feeding a single converter you will need one for each. Otherwise you just need to deal with the one.

O2 sensors work by comparing outside O2 levels against exhaust O2 levels. From this the O2 make a voltage reference that the ECU uses to determine how rich or lean the engine is running and makes the necessary adjustments to the injectors. The EFIE alters that signal to fool the ECU from thinking a too lean condition exists and making a richer mixture.

SmoothieV
07-05-2008, 09:08 AM
Gotcha, so I probably need 2 EFIE's because only the 3rd one is behind the cat?

h-power
07-05-2008, 03:09 PM
I have seen EFIE units that claim to be able to handle 2 O2 sensors in one unit. I have ordered one of these and I'm waiting to receive it.

troymacdonald
07-18-2008, 10:49 PM
I put together a much simplified O2 adjuster. how it works is by adding a minute amount of voltage to the sensor signal going to the computer. I have hooked it up to my truck. I have four sensors on the "V" style engine, two on each bank - one each before the cat and one each after. I only adjusted the ones before the cat.
To allow for reservability I used wire tap connectors on the lines from the sensor itself so I wouldn't have to cut and splice. I did a short run to the gas station to get a soda, only about 4 miles round trip. On the way back my Check Engine light came on.
Before I installed the O2 controller I bench tested the outputs and got a range from 0.00 to .24VDC, which I'm assuming would be enough to make a difference in so much as the HHO generator is concerned but not enough to stall the truck.
I did put a diode inline from each O2 sensor to keep the addtional voltage from damaging the senors themselves. What I'll have to do is find a way to test the voltage coming from the sensor and see what the reading is before the device and after the device but BEFORE the computer so I can see how much I'm actually adjusting it.
Since the Check Engine light came on I know I'm make some sort of difference. Now that the physical install is done its down to the testing phase. One thing mentioned earlier was the voltage drop across the diodes, so I might have to lower the resistance of my device to compensate.

ranger2.3
07-18-2008, 11:17 PM
You know what, I might swap in a carbureated fuel system in my truck, or just get rid of the four banger in my truck(which is fuel injected) and slap a carbureated V8 just for the sake of a simpler fuel system.