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EFIE for volts instead of millivolts
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Jeep Girl Offline
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Question EFIE for volts instead of millivolts
I have a 2005 Jeep Grand Cherokee with a 3.7 L V6 engine and a MagDrive water to gas system installed. The Eagle EFIE runs less than 1 volt. My O2 sensors should range between 2.5 & 3.4 volts. Is there an EFIE built for this range?
11-03-2008 12:00 PM
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mike Offline
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RE: EFIE for volts instead of millivolts
I believe you have a voltage reference being put on the "signal low" wire by the ECU. If you measure this wire to ground you should get a steady voltage there. It sounds like that will be 2.5 volts.

If you measure your signal wire with the red probe, and put the black probe on the reference wire, you should see voltage fluctuations in the range of 0 to 1 volt. Any EFIE will work with this. The reference voltage doesn't matter at all as far as the EFIE is concerned.

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11-03-2008 02:47 PM
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Jeep Girl Offline
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RE: EFIE for volts instead of millivolts
mike Wrote:I believe you have a voltage reference being put on the "signal low" wire by the ECU. If you measure this wire to ground you should get a steady voltage there. It sounds like that will be 2.5 volts.

If you measure your signal wire with the red probe, and put the black probe on the reference wire, you should see voltage fluctuations in the range of 0 to 1 volt. Any EFIE will work with this. The reference voltage doesn't matter at all as far as the EFIE is concerned.

Now I am confused. The manual says the correct operating voltage for all 4 sensors should be between 2.5 & 3.4 volts. I put on the EFIE from Eagle and the check engine light came on. It doesn't matter if I set the EFIE at 0 or 350 mv or 500 mv, the light keeps coming on after it is reset. I followed the directions when installing it, and connected it to the grey wire which is the signal wire. Should I have wired it to the return (upstream) wire instead?Crazy
11-03-2008 03:07 PM
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Jeep Girl Offline
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RE: EFIE for volts instead of millivolts
Now I am confused. The manual says the correct operating voltage for all 4 sensors should be between 2.5 & 3.4 volts. I put on the EFIE from Eagle and the check engine light came on. It doesn't matter if I set the EFIE at 0 or 350 mv or 500 mv, the light keeps coming on after it is reset. I followed the directions when installing it, and connected it to the grey wire which is the signal wire. Should I have wired it to the return (upstream) wire instead?Crazy
11-04-2008 01:26 PM
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alpha-dog Offline
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RE: EFIE for volts instead of millivolts
Jeep Girl Wrote:Now I am confused. The manual says the correct operating voltage for all 4 sensors should be between 2.5 & 3.4 volts. I put on the EFIE from Eagle and the check engine light came on. It doesn't matter if I set the EFIE at 0 or 350 mv or 500 mv, the light keeps coming on after it is reset. I followed the directions when installing it, and connected it to the grey wire which is the signal wire. Should I have wired it to the return (upstream) wire instead?Crazy

Hi Jeep Girl
I have a 2006 Dodge Ram with the same o2's that you have and I can tell you that you don't want to be on the grey wire ( pin 4 ). Instead use the black wire ( pin 3 ) and wire according to instructions.
Russ
11-04-2008 01:30 PM
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Jeep Girl Offline
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RE: EFIE for volts instead of millivolts
Dear Russ,
Thank you! At least I know know where I went wrong. Now the real nightmare begins, because those wires are in the most awkward place they could possibly put them! (unless you know a better place to find the wires than right off the O2 sensors themselves)
Jeep Girl
(This post was last modified: 11-04-2008 01:58 PM by Jeep Girl.)
11-04-2008 01:39 PM
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Jeep Girl Offline
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RE: EFIE for volts instead of millivolts
I spliced the grey wires back together again, and put the EFIEs on the black wires and set the mv to 350. My mileage went from 18 all the way up to 23 during a 15 mile drive into town! YAHOO!! Laugh
When I got back into my car the check engine light came on again. Crazy
Since the mv had risen to almost 400 I set it back down again to 350. The next trip my light came on again, so I tried 300mv. That didn't work either. Today I have it set at 220mv. I am going out in a bit and will report back again after I see if this works any better.
Jeep Girl
11-08-2008 05:26 AM
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colchiro Offline
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RE: EFIE for volts instead of millivolts
Depending on your cell's output/efficiency, you might need to go as low as 100 or 150mv. Bear in mind your results should dictate your setting, not just the presence of a CEL.

I usually suggest starting at 100-150 and work your way up in increments of 50 mv (days apart to give the ecu time to compensate) and stop when one of the following occurs:
CEL
loss of power or other driveability issue
no gain in mileage

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
11-08-2008 08:10 AM
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Jeep Girl Offline
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RE: EFIE for volts instead of millivolts
Thanks Rick. I didn't have any better luck at 220, so will go to 100 and try that. It is so frustrating to have it work for one run, than have the CEL go on when I start the car up again.
Jeep Girl
11-08-2008 11:11 AM
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colchiro Offline
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RE: EFIE for volts instead of millivolts
The next step might be to check your cell for output (liters per minute), check for leaks (brush the connections with soapy water) and report your findings along with the amperage (and plate configuration) you're using for input from users here (who are always happy to critique an install).

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
11-08-2008 11:37 AM
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