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EFIE Voltage Readings
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altaber@eztissue.biz Offline
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Post: #1
EFIE Voltage Readings
When I was hooking up my EFIE I stuck a needle into the grey/light blue wire to the computer and took a reading of 265 mv. I figured that I was on the correct wire and hooked the unit up. Plugged into the red and black sites on the unit I got a reading of .265 and based on your saying and info on the web site I figured that was OK for the pre set figure of .250. Ran two one gallon test on Monday evening from 8 to 10 pm and came up with 21 miles on one and 19 on the second. Did not have a chance to work with this yesterday as we were out of town all day. This morning I started up the truck and checked the red and black connections on the unit and read .265. Turned the unit up to where it read .440 and then went back to the signal from the O2 sensor and it was 40. Reading at that time from the unit was .436.
The reading from the unit (red & black) is what the computer receives, right? If that is the case should it not be above .500 to get the computer to reduce the amount of fuel?
I am ready to do some more test runs when I know for sure what I should be reading from the unit.
10-17-2007 01:26 PM
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mike Offline
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Post: #2
RE: EFIE Voltage Readings
Hi Al,

EFIE, General Information:
First of all, now that you have the EFIE installed, there is no longer any need to tap the oxygen sensor wire. You can just use the EFIE test ports. The black port always connects directly to the oxygen sensor. The red port always connects directly to the computer line. When the unit is off, the red and black are shorted out, thus making a direct connection between the oxygen sensor and the computer. When the unit is on, EFIE is adding it's voltage offset.

When you test between the black and the red test ports, you are not reading what the computer sees. You are reading the amount the EFIE is increasing the voltage that is coming from the oxygen sensor. You will find that this reading is stable, ie doesn't fluctuate around. It will rise until it reaches it's set voltage.

When you measure between the black port and your truck's frame, you're getting the voltage that the oxygen sensor is producing. When you measure from the red port to vehicle ground, you're seeing what the computer is receiving, or stated differently, you are reading the oxygen sensor's voltage plus the voltage produced by the EFIE. Both of these values should be constantly varying when the engine is running, but be in the range of .1 to .9 volt on the black port, and the red port will be the same range plus the EFIE offset voltage. However, note that the oxygen readings will not be correct until the oxygen sensor has had time to warm up. A reading of 40 millivolts from the oxygen sensor is incorrect and either means it hadn't warmed up yet, or is not functioning correctly. So these readings must be made after letting the engine run for a few minutes.

Answer to your specific questions
When you say "the reading at the unit is what the computer receives", the answer is, no. I'm assuming you mean when you test between the red and black terminals. See above. This is the voltage offset produced by the EFIE only. To see what the computer receives, measure from the red test port to ground.

The idea that the computer needs to see greater than .500 volts to get fuel savings is false. The computer needs the voltage from the oxygen sensor increased, however, is true.

The test from the light blue/grey wire to ground, will be the same as the black test port to ground. This is the oxygen sensor's voltage only. This is a constantly fluctuating voltage in the range of .1 to .9 volts, and most meters will show about .400 volts here as an average. But you're not actually reading a static voltage. You might try another meter and see what it says. An analogue meter (with a needle) would be great if you can get one, then you'll see the needle swinging around with the voltage changes from the sensor.

Something is wrong with the data you are giving me, or something is not hooked up correctly. You say you measured .265 at the grey/light blue wire (and i'm assuming the other probe was grounded, right?). Then later you say you're getting .04 volts (40 millivolts) at the oxygen sensor. Again I'm assuming you're talking about the black test port to ground. These 2 data don't add up, so I may not be understanding something.

Does this shed some light? If not, re-post, but when you report voltages, please specify where both probes are connected when making the reading. Saying the oxygen sensor wire is reading .265 doesn't help unless I know that the black probe was attached to ground.

Let me know how this goes.

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10-17-2007 02:23 PM
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altaber@eztissue.biz Offline
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Post: #3
RE: EFIE Voltage Readings
Mike, with the truck running and hot (30 minutes idle) I get a reading between red & black of 380, between black & ground 16 to 140 with mid 90’s a lot of the time, but varying a lot, between red and ground 488. I checked the black port figure against sticking the probe into the wire nut joining the wire from sensor to the EFIE (green wire) and the white wire to the other side of the grey/light blue wire to the computer.

Should not the voltage reported to the computer be above 500 to get any reduction in fuel consumption?.



Al
10-17-2007 03:00 PM
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mike Offline
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RE: EFIE Voltage Readings
No, Al, that isn't necessarily true. It appears that your oxygen sensor puts out a lower voltage range than I'm used to. That's either because it's the correct spec and the computer expects that range of voltages, or the sensor has gone bad. My guess is that that's just the range of voltages for that sensor. But it's a bit suspicious, because I'm accustomed to seeing a range around the .400 millivolt.

It might just be the characteristics of your tester too. If you can get another volt meter, test with that, and let me know if that changes your reading. Since it's a constantly changing voltage, your meter may just be reporting the lower end of the range, whereas most meters tend to give an average voltage.

A voltage level above 500 millivolts isn't the goal here. It's merely to get a shift from what the computer expects to see, to (in this case) 380 millivolts more than that. That's all. Usually we're not measuring the voltage coming off the oxygen sensor (to ground), unless we think something is wrong with the sensor.

I think you're fine there. How are the fuel mileage tests going? Have you realized an increase? If so, how much?

Oh, and last question: Has your check engine light been on, either before your started this project, or since? If your oxygen sensor is reading way out of spec, the check engine light would be on. The computer will complain about that.

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10-17-2007 07:46 PM
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01olds Offline
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Post: #5
RE: EFIE Voltage Readings
HI.. NOT SURE WHAT COMMENTS ARE ALREADY POSTED CONSERNING THE EFIE DEVICE.....HOWEVER ..AT ANOTHER SITE I REAR WHERE ABOVE 450MV. WAS CONSIDERED RICH MIXTURE ..WHICH WOULD CAUSE THE INJECTORS TO LEAN OUT ... NOT TO THE POINT WHERE IT HARM THE ENGINE *THEREFOR BELOW 450WAS CONSIDERED LEAN AND WOULD CAUSE THE INJECTORS TO RUN RICH..OR NORMAL. SO I HAVE NOW SET MY EFIE TO ABOUT 456....I,LL GIVE THAT A TRY .. OH GOSH THIS TRIAL AND ERROW STUFF ...UGH
10-25-2007 07:34 AM
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mike Offline
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Post: #6
RE: EFIE Voltage Readings
I'm not sure I understood what you're saying precisely. But the higher the EFIE setting, the leaner your engine will run. See the articles here for more information, particularly this one.

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10-25-2007 11:05 AM
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01olds Offline
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Post: #7
RE: EFIE Voltage Readings
NOT SURE ABOUT THAT! HIGHER EFIE SETTINGS LEANER BETTER.... HAVE TO SEE HOW IT WORKS WITH THIS CAR!!.. SO I,LL TRY THESE SETTINGS SEE HOW THEY RESPOND 450mv
10-25-2007 11:52 AM
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mike Offline
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RE: EFIE Voltage Readings
That setting may well be fine. I'm not saying it's a bad setting. I'm just saying that the more you increase the efie voltage offset, the leaner the fuel mix will be.

What type of fuel saver are you using with your EFIE?

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10-25-2007 08:24 PM
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altaber@eztissue.biz Offline
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Post: #9
RE: EFIE Voltage Readings
mike Wrote:That setting may well be fine. I'm not saying it's a bad setting. I'm just saying that the more you increase the efie voltage offset, the leaner the fuel mix will be.

What type of fuel saver are you using with your EFIE?
10-26-2007 11:19 AM
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mike Offline
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Post: #10
RE: EFIE Voltage Readings
Hi Al,

Were you trying to post a question? How are your mileage tests coming?

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10-26-2007 11:33 AM
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