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EFIE Connection
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sabre1pc Offline
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Post: #21
RE: EFIE Connection
(02-08-2012 09:18 AM)mike Wrote:  Something is wrong. It probably is the wrong wire. If it truly is the correct wire, then it sounds like a faulty sensor. Like maybe it's plugged up or something. Because that reading would be like it was seeing the richest possible mixture all the time.

Basically, it's either the wrong wire, or something is very wrong - bad sensor, or some kind of fault with the fuel injection system.

But my first guess is that its the wrong wire.

The Scanguage is not showing any other error code other than P0171 which means extra oxygen in my exhaust. The O2 sensors are brand new installed last week. This was the same issue before the sensors were replaced.
02-08-2012 11:57 AM
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mike Offline
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Post: #22
RE: EFIE Connection
Ok. Well that means that it's not the sensor. But still something is very wrong. That signal wire should be fluctuating between 0 and 1 volt. On your meter you should see values ranging from about .2 to about .9 volts and the values should be changing so fast its hard to keep track of.

The fact that you're not seeing this means something is wrong.

Measure the circuit again with the EFIE powered off. Just remove the 12V power wire. This will cause the relays to fall closed, and the sensor wire will be connected directly to the computer. Do you now see the voltage changing as I described?

If not, then are you absolutely sure you have the correct wire. It may seem obvious to you, but I can't see what you have. But if you have the correct wire, then something weird is going on, like your injectors are stuck open or something. Because that reading just isn't correct for an upstream narrow band sensor signal wire.

Also, what kind of car do you have? (make/model/year/engine size)

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02-08-2012 12:56 PM
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sabre1pc Offline
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Post: #23
RE: EFIE Connection
(02-08-2012 12:56 PM)mike Wrote:  Ok. Well that means that it's not the sensor. But still something is very wrong. That signal wire should be fluctuating between 0 and 1 volt. On your meter you should see values ranging from about .2 to about .9 volts and the values should be changing so fast its hard to keep track of.

The fact that you're not seeing this means something is wrong.

Measure the circuit again with the EFIE powered off. Just remove the 12V power wire. This will cause the relays to fall closed, and the sensor wire will be connected directly to the computer. Do you now see the voltage changing as I described?

If not, then are you absolutely sure you have the correct wire. It may seem obvious to you, but I can't see what you have. But if you have the correct wire, then something weird is going on, like your injectors are stuck open or something. Because that reading just isn't correct for an upstream narrow band sensor signal wire.

Also, what kind of car do you have? (make/model/year/engine size)

2007 Hummer h3 3.7 ltr 5 cyl.
When i had the upstream sensor connected to the 3 & 4 connectors the voltage was a steady 1.1 volts. I tried connecting the upstream to the open analog connectors and thats when the voltage on that sensors started to fluctuate between 299 mv to 1.1 volts. Does that mean the sensors is an analog and should be connected there? Will it harm the EFIE or the sensor if I test the vehicle connected this way?
   
02-08-2012 04:49 PM
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mike Offline
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Post: #24
RE: EFIE Connection
No. No harm will come to either. Both EFIEs are for narrow band sensors, and both of your sensors are narrow band. We've just found that USUALLY, digital EFIEs work better on upstream sensors and analog EFIEs work better on downstream sensors. It doesn't have anything to do with the sensors themselves, but has to do with the type of signal they'll generate due to their location (before and after the cat).

You can find out more about why that is in this article: http://www.fuelsaver-mpg.com/the-digital...w-it-works

By the way, I looked up your vehicle in Alldata and it definitely has 2 narrow band sensors, as I'm sure you've already determined.

You must have a Quad Digital EFIE, is that right? If so, it's perfectly OK to use both analog EFIEs on your 2 sensors. Usually it works better with the digital EFIE, but it appears you hooked it up correctly, and there is some incompatibility going on there. The problem we face making EFIEs is that there is really no limit to the types of things the computer can do with those sensor signals. Its pretty rare that a digital EFIE has a problem - and I'm not totally convinced that a different setting wouldn't work better - but we used to use analog EFIEs exclusively for both front and back sensors with a great deal of success. So, it's OK to do so if that is working for you.

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02-09-2012 08:40 AM
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sabre1pc Offline
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Post: #25
RE: EFIE Connection
(02-09-2012 08:40 AM)mike Wrote:  No. No harm will come to either. Both EFIEs are for narrow band sensors, and both of your sensors are narrow band. We've just found that USUALLY, digital EFIEs work better on upstream sensors and analog EFIEs work better on downstream sensors. It doesn't have anything to do with the sensors themselves, but has to do with the type of signal they'll generate due to their location (before and after the cat).

You can find out more about why that is in this article: http://www.fuelsaver-mpg.com/the-digital...w-it-works

By the way, I looked up your vehicle in Alldata and it definitely has 2 narrow band sensors, as I'm sure you've already determined.

You must have a Quad Digital EFIE, is that right? If so, it's perfectly OK to use both analog EFIEs on your 2 sensors. Usually it works better with the digital EFIE, but it appears you hooked it up correctly, and there is some incompatibility going on there. The problem we face making EFIEs is that there is really no limit to the types of things the computer can do with those sensor signals. Its pretty rare that a digital EFIE has a problem - and I'm not totally convinced that a different setting wouldn't work better - but we used to use analog EFIEs exclusively for both front and back sensors with a great deal of success. So, it's OK to do so if that is working for you.
Will the Quad Digital EFIE I have work as well as any other EFIE or should I get a different model?
Should I set both lower analog EFIE's at 350mv?
(This post was last modified: 02-09-2012 12:16 PM by sabre1pc.)
02-09-2012 11:59 AM
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mike Offline
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Post: #26
RE: EFIE Connection
The downstream (analog) EFIEs are set with another pot. You'll end up with both analog EFIEs set the same. That's OK. That is usually the best way to do it.

Before digital EFIEs when we only had analog EFIEs, that was the usual set up. Both EFIEs set the same amount for upstream and downstream.

350 is pretty high. I would start out around 200 mv. See how that does. Then try higher values until you maximize your mileage gains. You can also try the old trick of raising the voltage until the engine lugs down, and then back off until it runs freely again. However, many modern cars won't do that because the computer never lets the fuel flow drop below a certain point. So the engine won't lug down.

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02-09-2012 01:45 PM
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sabre1pc Offline
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Post: #27
RE: EFIE Connection
(02-09-2012 01:45 PM)mike Wrote:  The downstream (analog) EFIEs are set with another pot. You'll end up with both analog EFIEs set the same. That's OK. That is usually the best way to do it.

Before digital EFIEs when we only had analog EFIEs, that was the usual set up. Both EFIEs set the same amount for upstream and downstream.

350 is pretty high. I would start out around 200 mv. See how that does. Then try higher values until you maximize your mileage gains. You can also try the old trick of raising the voltage until the engine lugs down, and then back off until it runs freely again. However, many modern cars won't do that because the computer never lets the fuel flow drop below a certain point. So the engine won't lug down.
I turned the pot clockwise and it did not go above 450mv. The engine did not lug down. If the pot is turned beyond the 450 mv does that lean the fuel even more?
02-09-2012 02:52 PM
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mike Offline
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Post: #28
RE: EFIE Connection
I can't answer your question unless I know if you are adjusting the upstream or the downstream EFIEs. But I can tell you this: The extremes of the adjustment ranges are never a good setting. The good settings will be somewhere closer to the middle.

Not all vehicles will lug down. That's up to the computer program for your car. Many of them have minimum fuel flows, so if you give signals that would cause the fuel to go lower than that, they won't. In these cases the engine won't lug down.

But you should re-read the online instructions. All of this is covered there in more detail.

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02-10-2012 10:48 AM
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