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Beginner needs help with homemade EFIE
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mrbriteside1465x2 Offline
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Question Beginner needs help with homemade EFIE
Hello, my name is Sean and I am having issues with the circuit I designed to regulate the amount of fuel my car is using. I will do my best to explain everything to you and anything you can tell me will be a great help.



First off, I have a 1994 Jeep Wrangler S 6cyl.

There is one oxygen sensor upstream (engine side) of the catalytic converter.

The engine is fuel injected.

The oxygen sensor has 4 wires. 2 white wires, 1 grey wire, and one black wire. I did testing on the black and grey wires to see which one was the signal wire, and surprisingly, the black one turned out to be it. I had assumed that the grey wire would be the signal, but when connecting the multimeter to it, i found that the grey wire was ground and the black was signal. I am attatching the device to the wires right next to the sensor.

In conjuction with the efie, I am using a homemade HHO generator as a fuel source in addition to gas.



Efie Wiring

(sorry for the lack of correct termonology, I am new to all of this and dont know specifics)

The O2 signal wire connects into the eife and into a single pole, ON-OFF-ON switch. One side of this switch goes directly to the ECU (to use the normal O2 sesor readings), and the other side of the switch goes through 2, 1.5 v AAA batteries. Then it goes to an ON-ON toggle switch. One side of the switch takes the now over 3 v charge to a potentiometer. A very small red LED is hooked up to the positive charge just before the potentiometer, and the negative side of the LED is attatched to a ground wire. After the Potentiometer, the charge goes back to the wire of the O2 sensor that takes it to the ECU. The other side of the toggle switch is the same exact thing. I did a toggle to have 2 different settings. Now the way the 4 grounds are connected, (2 potentiometers, 2 LEDs) , they all come together to one wire and this ground wire is connected to the same ground wire that the o2 sensor uses. The way the signal wires work (2 pot wires, 1 wire from the very first switch) They come together to 1 wire which connects back to the o2 sesor wire to take the charge back to the ECU.



Efie Problems

I think that the way I have my circuit wired is very wrong. When I install this system on my vehicle, I attatch a multimeter to the ground wire and to the signal wire going to the ECU to monitor the voltage. After the car is running warm, I read the settings and play around with it. When the original switch is flipped to the side that is supposed to use the orgininal o2 sensor readings, it does not do so at all, and the potentiometers still have an effect on the voltage. When the first switch is in the off position, there is still a voltage going to the computer, which is also still effected by the potentiometers. Also, i am having a very difficult time keeping the voltage of the output under .90, which is way to high to acutally use. Could all of these problems be due to the fact that i wired the ground wires all together before actually going to the o2 ground, and that i wired the signal wires together before goign to the ecu? I am very confused at this. I am very assured that there are no "stupid" mistakes like a touching wire or mismatched wire or anything like that. I just cannot figure out why it is not working for me.



I apologize if you are having trouble picturing exactly what is going on, please email me back for clarification on anything. any information you have that could help would be extremely appreciated.

Thanks A LOT,

Sean
(This post was last modified: 02-20-2009 02:14 PM by colchiro.)
02-20-2009 01:45 PM
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colchiro Offline
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RE: Beginner needs help with homemade EFIE
Hi Sean.

I would have expected the heater wires to be the same color (white-white or black-black), otherwise anything goes for the sensor wires.

The installation and adjusting will be the same as the "EFIE Installation Instructions" in my Documents link.

An oversimplified diagram would be this:

o2 sensor ---- |+|+ ----- ECU

... with the pos battery terminal toward the ecu.

To measure your offset, simple connect your black meter lead to the o2 wire and the red lead to the ecu lead. We normally would see 50mv to 450mv DC, with 100-200 mv a more normal setting.

A diagram of your efie has been posted here in the last year or so, but I can't find it. The on/off switch should connect the ecu to the o2 sensor, bypassing everything else.

Do you have a picture of your wiring you can post here? Without it, it's very difficult to troubleshoot.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
02-20-2009 02:37 PM
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AlexR Offline
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RE: Beginner needs help with homemade EFIE
(02-20-2009 01:45 PM)mrbriteside1465x2 Wrote:  First off, I have a 1994 Jeep Wrangler S 6cyl.

Sean,

My first vehicle I started mods on was a 1993 Jeep Wrangler with a 2.5 liter 4 cylinder engine.

Mine had an oddball Peugeot computer in it. Does yours have that too? You may not even know unless you talk to a mechanic knowledgeable on that vehicle.

I added deceleration fuel shut off and gained 20% to almost 30% mileage in city and country driving.

In my experience the EFIE wasn't enough to get a mileage gain, I think you'll need to do mods to the IAT and MAF also. I could be wrong though, I didn't finish everything I wanted to do as it got rear-ended and the insurance company totaled it.

Alex

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02-20-2009 03:15 PM
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mrbriteside1465x2 Offline
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RE: Beginner needs help with homemade EFIE
Hello, Here is a diagram of the wiring. it is a very simple Paint diagram, sorry about the lack of professionality.

Im wondering if the problem comes from where the ground wires and the signal wires all are soldered together before going to the computer?

Does the ground have to be connected to the ground it is connected to now? or could it be simply grounded to the body of the car or anywhere else?

Should the LED's be wired like this or a different way?

any wiring problems you see please let me know.
Thanks


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02-20-2009 06:06 PM
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colchiro Offline
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RE: Beginner needs help with homemade EFIE
I thought it was a nice picture. Wink

I think the problem is the pots are grounded and the switch doesn't completely isolate them with the unit is switched off. Looks like you have a city/highway setting. You could switch one pot so you have the maximum resistance between green and black and just use the other pot and switch both switches to turn it off/on.

Option 2 would be to have a DPDT swith for the on/off and switch the green wires at the top. ECU to center of second half and switch and pots for the other terminals.

Are you sure you're supposed to have 3 volts, and not 1.5 volts (both batteries in parallel)?

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
02-20-2009 07:26 PM
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AlexR Offline
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RE: Beginner needs help with homemade EFIE
Is the polarity reversed on your diagram also?

Alex

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02-21-2009 05:22 AM
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colchiro Offline
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RE: Beginner needs help with homemade EFIE
pos needs to go toward the ecu to add to the o2 sensor voltage. Looked ok to me.

I don't think using 3 volts to get a 200 mv increase in signal is too efficient. Rewiring to have both batteries in parallel (1.5 volts) makes more sense to me. I think the last design I saw like this had only one battery, one pot and no led's.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
02-21-2009 07:29 AM
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