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Dodge, voltage offset bias, and the dual "grey box" EFIE
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CrazyJoey Offline
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Post: #1
Dodge, voltage offset bias, and the dual "grey box" EFIE
In the last few weeks on working on my wife's partner's 2009 Dodge Ram 1500 SLT HEMI, I have learned a couple of things:

1. I hate Dodge. Smile
2. 2.5V bias on their O2 sensor system.

Alright, so we got the new quad EFIE, and it doesn't work. So, on a suggestion from a very well informed source Smile , we went back to trying the Deluxe EFIE that's in the grey box. We used two of those boxes to treat all four O2 sensors. I have a question, (or maybe two):

1. If the O2 sensor system in this Dodge truck is showing a bias of 2.5V, should my starting point be really high, like 250mV, instead of the 200mV that's stated in the install instructions of the Deluxe EFIE?

2. Am I correct to assume that the O2's ".45" line is really .70 because of this biased condition? (.45 norm + .25V bias = .70)

I have looked on the forums for any ending results or gains from people that have Dodge/Chrysler trucks, but I couldn't find anything.

Thanks,
Joe
06-12-2009 01:28 PM
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mike Offline
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Post: #2
RE: Dodge, voltage offset bias, and the dual "grey box" EFIE
(06-12-2009 01:28 PM)CrazyJoey Wrote:  In the last few weeks on working on my wife's partner's 2009 Dodge Ram 1500 SLT HEMI, I have learned a couple of things:

1. I hate Dodge. Smile
2. 2.5V bias on their O2 sensor system.

Alright, so we got the new quad EFIE, and it doesn't work. So, on a suggestion from a very well informed source Smile , we went back to trying the Deluxe EFIE that's in the grey box. We used two of those boxes to treat all four O2 sensors. I have a question, (or maybe two):

1. If the O2 sensor system in this Dodge truck is showing a bias of 2.5V, should my starting point be really high, like 250mV, instead of the 200mV that's stated in the install instructions of the Deluxe EFIE?

2. Am I correct to assume that the O2's ".45" line is really .70 because of this biased condition? (.45 norm + .25V bias = .70)

I have looked on the forums for any ending results or gains from people that have Dodge/Chrysler trucks, but I couldn't find anything.

Thanks,
Joe

Hi Joe,

I'm very sorry for your troubles with the Dodge. We will be amending our page in the store so that people who have this reference voltage let us know, and we'll send out a modified EFIE thats just for the Dodge (like we did for you). That was our bad. Our design intention was that the EFIE would work when grounded to the signal low, but it just doesn't let enough current flow on that wire to power the EFIE fully. This was our first chance to test it on a Dodge, so, unfortunately, you were our guinea pig.

As to your questions. The older style EFIEs do not need to be grounded to the sensor's signal low. They would also not work, as they actually draw more power than the digital EFIE. However, they don't care what reference voltage is used at the sensor. They will work fine. Just install them as per the instructions (EFIE Installation Instructions).

Your math is incorrect. The startning point isn't .25V, its 2.5V. So the output of the oxygen sensor will be 2.5 to 3.5. But the thing you have to realize is that with the Analog EFIE, it just doesn't matter what the reference voltage is. It's completely invisible to the EFIE. The EFIE is going to add a voltage to that signal wire. The amount you'll want to add is about .25 volts or so. You'll adjust this as per the instructions, but don't go up as high as .4 and below .1 is too low.

Don't let the 2.5 volt reference confuse you. It is completely invisible to the old style EFIE, and can be safely ignored as a factor.

Mike

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06-12-2009 02:41 PM
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CrazyJoey Offline
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RE: Dodge, voltage offset bias, and the dual "grey box" EFIE
(06-12-2009 02:41 PM)mike Wrote:  Hi Joe,

I'm very sorry for your troubles with the Dodge. We will be amending our page in the store so that people who have this reference voltage let us know, and we'll send out a modified EFIE thats just for the Dodge (like we did for you). That was our bad. Our design intention was that the EFIE would work when grounded to the signal low, but it just doesn't let enough current flow on that wire to power the EFIE fully. This was our first chance to test it on a Dodge, so, unfortunately, you were our guinea pig.

As to your questions. The older style EFIEs do not need to be grounded to the sensor's signal low. They would also not work, as they actually draw more power than the digital EFIE. However, they don't care what reference voltage is used at the sensor. They will work fine. Just install them as per the instructions (EFIE Installation Instructions).

Your math is incorrect. The startning point isn't .25V, its 2.5V. So the output of the oxygen sensor will be 2.5 to 3.5. But the thing you have to realize is that with the Analog EFIE, it just doesn't matter what the reference voltage is. It's completely invisible to the EFIE. The EFIE is going to add a voltage to that signal wire. The amount you'll want to add is about .25 volts or so. You'll adjust this as per the instructions, but don't go up as high as .4 and below .1 is too low.

Don't let the 2.5 volt reference confuse you. It is completely invisible to the old style EFIE, and can be safely ignored as a factor.

Mike

Ah, it's okay. I appreciate your patience in me. Frankly, I'm learning automotive electrical engineering on the fly here. I'm a computer tech by day. If this was a computer, it would be super easy. Smile
06-12-2009 07:15 PM
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mike Offline
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Post: #4
RE: Dodge, voltage offset bias, and the dual "grey box" EFIE
(06-12-2009 07:15 PM)CrazyJoey Wrote:  Ah, it's okay. I appreciate your patience in me. Frankly, I'm learning automotive electrical engineering on the fly here. I'm a computer tech by day. If this was a computer, it would be super easy. Smile

Well, most of the trouble you ran into was the fact that our unit wouldn't work on that vehicle as we had planned. So that's on us. You'll find that hooking up EFIEs gets real simple after you've done a couple more. The first one is always the most confusing, even if you don't have a situation like you did where the unit wouldn't work on the vehicle.

As a note about that, we are now set up to modify the EFIEs for Dodge owners. We'll be letting them know that they must tell us if they have the 2.5V reference so we can send them a unit modified for that environment. We didn't anticipate that the small current draw of our unit would max out that 2.5V reference circuit.

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06-13-2009 01:15 PM
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