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EFIE voltage question
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Chef Kevin Offline
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Post: #1
EFIE voltage question
I have my 2001 Taurus with 2 EFIEs. 1 I bought here from Mike, and one that looks identical from another source.

My check engine light has been on forever. So, when it was checked a while back I was told bad O2 sensor.

I already had 2 EFIEs installed so I got out my multimeter and the front O2 sensor (v6 is sideways in a taurus) reads a .284 offset (as it came from Mike). The back O2 sensor read an offset of 5.6 (I was like "what the...") so I figured it was the bad one. I went and bought the O2 sensor. Installed the new one, and then the number was.... 5.6.
The pre-EFIE reading was 13.something. I am at a loss.
Why is one reading 13. and the other reading .45 pre efie.

Shouldn't it be about the same?
I am going to have the error code cleared tomorrow and I am hoping it fixes it. But what could be causing this? This seems very odd to me.
Plus, before changing this sensor, my mieage dropped back to 24mpg. not the 32+ I had.
06-09-2008 04:27 PM
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mike Offline
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Post: #2
RE: EFIE voltage question
It sure should. I'm not sure what you're reading there, but it's not an oxygen sensor signal wire. 13 volts sounds like a power wire. Like maybe the power for the sensor's heater or some such. Find the signal wire. It will fluctuate like bad when the engine is running between .3 and .7 volts (average of .45 volts) or so.

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06-09-2008 10:48 PM
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Chef Kevin Offline
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Post: #3
RE: EFIE voltage question
that's the crazy part. I hooked up the EFIE to the same wire on both sensors. crazy....

I guess I'll keep poking around!
06-10-2008 03:03 AM
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Chef Kevin Offline
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Post: #4
RE: EFIE voltage question
ok, so I cracked open the 2 EFIEs. Mike, Yours was set perfectly.
the other, although looks just like it, is not so simple inside. Not nearly as nicely made. I found an adjustment screw and was able to get a signal from it.
It seems that it is reading on the meter at 10x the signal strength as the other o2 sensor. I made some adjustments to it and we shall see. I wish I knew this site existed b4 I bought the first EFIE. I would have 2 EFIEs from Mike if I did.

So, I looked at the other "brand x" EFIE and saw it was a 20k pot. Mike, Is yours 20k or 200K and could that be the reading difference?

thanks!!
Kevin
06-10-2008 03:58 PM
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Chef Kevin Offline
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Post: #5
RE: EFIE voltage question
one more thing.
after reading the various descriptions...
the EFIE from mike it the fixed resistor type.
the other is the adjustable kind. I had to adjust it on the inside to get any effect.
06-10-2008 04:05 PM
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mike Offline
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Post: #6
RE: EFIE voltage question
Kevin, I'm not actually following your last 2 questions.

The resistors and pots that are used don't really make any difference. That's just the design used to get the adjustable voltage offset. It's the result you want, which is the voltage offset that will be added to your oxygen sensor's signal. That voltage should be in the range of .1 to about .4 volts or so. If an EFIE can do this, then it works. The design of how it achieves this is not important. This goes for the brand X efie too.

If you're saying the other EFIE is putting out 12 volts, then you gotta get it off of there.

You'll probably want to use my documents page for more information on the subject: http://www.fuelsaver-mpg.com/documents.html

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06-11-2008 12:01 PM
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Chef Kevin Offline
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Post: #7
RE: EFIE voltage question
i turned it off when I was getting these crazy readings.
I am stumped at what to do. I read the documents you have posted, but they just aren't helping me in my situation. I think there is something just not right on my car.

I have the haynes manual out and i looked at the diagram for the sensor. My book says the black wire is the signal wire so I tapped into it. The old O2 sensor on the front of the engine is working fine and I have the EFIE on the black wire.
Of the 4 wires, it is in the lower right hand side of the connector plug.

So, on the new O2 sensor (back side of the engine) I tapped into the only black wire and it is also in the same position on the connector plug. But is gives me way higher readings.
Even with no power to the EFIE, the readings are 4.0 to 7.1 or so. I haven't seen a 13 today, but I did get one 2 days ago.
06-11-2008 12:17 PM
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Chef Kevin Offline
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Post: #8
RE: EFIE voltage question
Here is the color scheme.....

Heater 12V - White
Heater Ground - White
O2 signal - Black
O2 Signal ground - Gray
06-11-2008 01:04 PM
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mike Offline
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Post: #9
RE: EFIE voltage question
I may be confused on a point here: Are these voltages appearing when the EFIE is not installed, or turned on? If not, then take the EFIE off the circuit and measure the sensor's signal wire only.

If this voltage is coming from the sensor's signal wire, then I don't know what more I can tell you. You are not on an oxygen sensor signal wire if you're getting 13 volts. It's something else. When you find the signal wire, you'll find that it reads an average of .45 volts (compared to ground) and is constantly changing. This is of course with the engine running and the sensor connected.

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06-13-2008 06:59 PM
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Chef Kevin Offline
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Post: #10
RE: EFIE voltage question
i have no clue. i am giving up.
ripping all of it out.

I have it on the signal wire because I hooked it up to the O2 sensor when I put the new one in. it's in the wire on the sensor itself fresh out of the box.

I give up. the oil companies win. the car companies win. My car doesn't match the repair books or anything. it's a big joke.
06-15-2008 03:00 PM
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