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Efie's just bought
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hydrogenpro Offline
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Post: #1
Efie's just bought
This is from my buddy who has a good question.
I read the instructions and noticed that your EFIEs can be used with AF sensors.

I bought a set of them for the sensors on both sides of my truck.
Toyota Tundra - 2 neutral wires, 1 constant 13V wire, 1 fluctuating signal wire.

My A/F sensor signal wire goes up to 12 volts, averaging anywhere from 4 - 6V and 6 - 8V depending on idle vs. various driving conditions
Supposedly, it should be at 3.3V for a neutral computer reading at 14.7:1 AFR.

Do I hook up the wires opposite of the narrow band O2 sensor directions, so that the voltage is subtracted?
If so, (I already tried it). The engine light goes on at about 4 turns clockwise as the ECU goes into 13V limp mode- no problem, I re-set it.

at 3.5 turns clockwise, I think I have a voltage reduction (hard to tell with the fluctuations). But it is still higher than 3.3V average
But I did not leave it on long because the POT gets hot and I do not know how hot they can get before overloading.
At 12V, the wattage is much higher than a 0 - 1V O2 sensor - but I have not tested it.
I preferably want to hook it up and go - not experiment or actually learn anything to make it work.

Will the POT handle the load?
From my understanding, the amps approach 0 as the volts approach 3.3V and amps get higher as volts do. I have not done an accurate amp or watt measurement.
What wattage is the trim resistor? Will the other resistors or components be affected by high loads first? what will burn out first? The answer I am hoping for is nothing will burn out and it will work perfectly on broad band sensors, but please help me get this vehicle figured out with what ever accurate info you can send my way.

In a Nutshell... Can these units work for A/F sensors (broad band) and how should they be installed?
Can you advise?

Kirk
10-01-2008 06:59 AM
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mike Offline
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Post: #2
RE: Efie's just bought
AFR sensors don't go up to 12 volts on the signal wire. You probably have the heater wire. The heater on wideband sensors doesn't get a constant 12 volts. The ECU modulates the heater power voltage to maintain a constant temperature at the sensing elements.

You haven't got the correct wire identified yet, and need to find it. When you find it it will be in either the 3.3 volts or 2.7 volts range. If you have an AFR sensor there will be 2 wires in the same range, and one of them will fluctuate slightly. That's the signal wire.

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10-01-2008 07:27 AM
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hydrogenpro Offline
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RE: Efie's just bought
mike Wrote:AFR sensors don't go up to 12 volts on the signal wire. You probably have the heater wire. The heater on wideband sensors doesn't get a constant 12 volts. The ECU modulates the heater power voltage to maintain a constant temperature at the sensing elements.

You haven't got the correct wire identified yet, and need to find it. When you find it it will be in either the 3.3 volts or 2.7 volts range. If you have an AFR sensor there will be 2 wires in the same range, and one of them will fluctuate slightly. That's the signal wire.

I'm fairly sure I hooked up to the right wire. It is not my first time tapping into electrical or tracing wires. But please read below and hopefully you will point out a fixable solution to the problem.

There are 4 wires on each sensor
2 are spliced together by the factory immed. after the sensor plug and are grounds
1 has a steady 13 volts
1 has a fluctuating voltage of 4-8 volts. Normally about 6 + - when at idle with the ac off.

I tapped into the fluctuating wire which I determined to be the signal wire.

This must be the wire and it does have a fluctuating 4-8 volts according to the voltmeter.

Any suggestions? Sorry if this gets long, but great questions and will help big time if you can answer them. thanks.
Is it a different type of sensor than an A/F?
Is it an A/F with higher than normal voltage readings? Even though I replaced the sensors with new ones and came to the same results.
Although I used 5 different voltmeters, could the reading be innacurate?
What wattage can the EFIE handle? At open loop it is 13V and undetermined amperes. But I know with A/F sensors that the amps are greater the farther from 3.3 volts it goes. I will test for the amps soon.
Normally - would this EFIE be hooked up in reverse to subtract voltage?
Lower volts means richer to the ECU which would make the ECU lean out the Air fuel ratio

theory: Possibly it is not an A/F sensor? Could there be other types of sensors made in 2005?
Possibly it is just reading rich so the volts are higher than normal?
Possibly the voltage is not being read accurately do to a factor not considered - like connecting to the chassis ground instead of completing the circuit through the ECU? Or another unknown.

I would love the problem to be because I used the wrong wire, but is probably something else - hopefully with a solution,

I'll take any ideas and theories at this point. Thanks!
10-01-2008 05:31 PM
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colchiro Offline
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RE: Efie's just bought
My Toyota has a constant 3.0 VDC and a fluctuating 3.3 VDC lead. From what I've read, this has been the case for most Toyotas since '99. What you describe complete news to me.

OTOH, we just found out that newer Dodge vehicles seem to use a narrow band o2, but with a voltage higher than the usual 0-1 VDC, with the same 1 volt variation.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
10-01-2008 06:23 PM
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mike Offline
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RE: Efie's just bought
I've never heard of anything like that either. What is your make/model of truck? Something is way out of whack about this.

As colchiro points out, we just learned that Dodge is using a narrow band sensor that works at higher voltages. But it's the same sensor that they apply a bias to. It still works the same as any other narrow band sensor. I've never even heard of an oxygen sensor that varies that much. Ever.

Are you sure you are reading the correct range from your meter? Are you sure you're reading the wires that come from your oxygen sensor? Are you reading the wires while the engine is running and the sensor is plugged in?

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10-02-2008 08:05 AM
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hydrogenpro Offline
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RE: Efie's just bought
2005 Toyota Tundra Double cab. 4.7 liter, 8 cylinder
10-02-2008 09:54 AM
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mike Offline
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RE: Efie's just bought
Please answer my other questions. I'm not there, so can't see what you have. I suspect you have wires for another sensor. Are you tapping the wires by the sensor, so that you can see that this isn't so? Or are you depending on the wire colors to be correct in a circuit diagram? In other words, can you bet your life that you have the 4 wires that lead to that sensor?

If so, please list again the voltages on each wire, when measured against a good ground. This is while the engine is running and warmed up for a minute or 2.

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10-02-2008 12:18 PM
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colchiro Offline
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RE: Efie's just bought
I would think that's the same air-fuel sensors as I have on my 2005 Rav4.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
10-02-2008 02:20 PM
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hydrogenpro Offline
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Post: #9
RE: Efie's just bought
Please re-question any of my answers if they are not clear.
Please answer my questions and throw in any info that might give me a clue.
Thanks,

Wire colors
on truck / on sensor / volts
purple blue 0
pink white 0
yellow black 3 to 9 volts( mostly 5 to 7)
white/rd black 13.0 volts (I used 4 different voltmeters - 12.8v, 12.9v, 13.0v, 13.0v)


Q1 - Yes I tapped the signal wire by the sensor and can see all the wires and colors on both sides of the plug
Q2 - No, I'm not depending on any color codes or diagrams, just using the fluctuating voltage as the determinant. I based my wire selection by voltage readings alone, without even looking up the wire colors.

Q3 - I would bet my life that there are no other wires than those 4. bear in mind... I have even replaced the sensors with new ones, so I know what is there. I even see that the 2 ground wires are factory spliced together before they go into a harness and travel out of sight. That leaves 2 hot wires... and the white with red stripe has a solid, steady 13.0 volts. The remaining wire is fluctuating like a signal wire is supposed to, but the readings are high.

I am measuring the volts with a regular multimeter. I read online that an accurate reading cannot be obtained that way, and you need to hook into the computer. Something about a scanner PID. This was wikipedia, but was somewhat choppy in the explaination and wording.
Any idea what they were talking about?
How do you measure your A/F sensor signal wires?
Are you baffled as me yet? I've wired my share of EFIEs on regular narrow band sensors without any problems.

Could this be a different type of sensor?
Could it just be a broad range A/F but so far off the norm for some reason... even though the truck runs perfectly?

Remember, the A/F sensor signal is actually the amps. And the amps rise as the volts rise ( do not know at what exponential rate). At 3.3 volts the amps approach 0. So an EFIE in reverse should bring down both, and cause a leaner fuel mixture... if the resistors in the EFIE can handle the load. But the watts are higher when the volts get higher. How high - not sure, but enough to heat the trimmer on the EFIE past the comfort zone.
10-02-2008 03:55 PM
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colchiro Offline
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RE: Efie's just bought
Was this vehicle working ok prior to adding the efie? Mileage close to epa estimates? Even with the new o2's? Were they factory sensors?

The voltages I quoted were with the engine running for a few minutes and idling and efie off. Assuming your engine is similar to mine, I go into closed loop within 15 seconds or so after starting.

All voltages should be measured to a good ground and a voltmeter is close enough to determine the wiring. It's not good enough to troubleshoot the sensor or tell you anything else useful, which is probably what your source was referring to.

My sensor has two wires the same color for heater (blk/blk), my 3.0 VDC line is white and the variable sense wire is blue with 3.5 VDC.

The sensor does work by changing current flow, but it is very small like 20 ma.

Your blue and white wires have 0 volts on them, which I find puzzling. My experience is when you have two wires black or 2 wires white, they are usually the heaters.

I doubt you'd have a new type of sensor since you have a 2005 and I would thing we would have heard about it by now with 2009's coming out soon.

I wouldn't turn on your efie until you get this figured out, especially if it's running hot.

Rick

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10-02-2008 06:06 PM
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