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AFR or O2
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numberonekiwi Offline
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Post: #1
AFR or O2
From readings in this forum if Your O2/AFR sensor is in the millvolt range it is most likely a O2 sensor However Mine has 1 red 2 black and 1 white wire which is around 2.5 volts when disconnected the white wire has 5volts So would I be correct in assuming it is an AFR rather than an O2 sensor

When I disconnected it from the ECU I notice it more difficult to start and it runs at a higher RPM (however I dont notice as much odor from the exhaust pipe as I do with it connected with it disconnected I obviously have the check engine light on

With my observation of less odor from the exhaust and higher idle RPM does this mean I am using less gas or more ?

I have a Nissan Cefiro / Maxima 1994 2 litre V6
04-20-2008 05:43 PM
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mike Offline
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Post: #2
RE: AFR or O2
You'll be using more gas. When the engine doesn't get sensible data from it's afr sensor, it will then make the mix extra rich. It will avoid making the mix too lean by guessing on the rich side. Your mpg will drop quite a bit if you were to drive with it like that for a while.

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04-20-2008 06:41 PM
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numberonekiwi Offline
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Post: #3
RE: AFR or O2
mike Wrote:You'll be using more gas. When the engine doesn't get sensible data from it's afr sensor, it will then make the mix extra rich. It will avoid making the mix too lean by guessing on the rich side. Your mpg will drop quite a bit if you were to drive with it like that for a while.

That I can confirm My estimate would be about 350 ~ 400 % more gas estimate worked out by

Normal gas consumpution around 8 Km / Ltr

I had 20 Km since last fill drove 9 Km unplugged then filled up 7 liters

so 20 Km used would be about 2.5 Ltrs - 7 Ltrs = 4.5 lts for 9Km very uneconomical

Also the engine would not run past 3200 RPM (check engine light = safe mode to get home/mechanics)

More study is needed
04-21-2008 02:38 AM
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mike Offline
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Post: #4
RE: AFR or O2
Look at Tuning For Mileage. It has information on how to modify an AFR sensor's data. She'll be right mate.

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04-21-2008 03:47 AM
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numberonekiwi Offline
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Post: #5
RE: AFR or O2
I reconnected my AFR sensor last night after refilling the tank as previously said I travelled about 29 KM again and refueled this evening only took 1.25 Ltrs I could not get any more gas in the tank this is with no HHO generator just stock I am now very confused as to why I am getting 22 Km / Ltr stock will try another tank top up shortly to see what happens
04-22-2008 02:43 AM
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mike Offline
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Post: #6
RE: AFR or O2
I'm a little confused about what you're question is. But you'll definitely get poor gas mileage, with or without HHO, if you have your AFR sensor disconnected. The reason is, that when the ECU sees no sensor there, it will immediately and at once go to a very rich mix. This will cause bad gas mileage, and no amount of HHO will change that.

To increase mileage with HHO you must have a good working sensor, and then you must modify it's data so the ECU sees a richer condition than the sensor is reporting. This will cause the ECU to lean the mix down. If you modify the data too much the ECU will again think the sensor is broken and will again go super rich. So a little bit is good, but a lot is not better.

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04-22-2008 07:06 AM
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Jeephigh_11 Offline
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Post: #7
RE: AFR or O2
Mike,

I'm in the same boat as #1, I have a 2007 Jeep Patriot 2.4 L, I've had my fuel warmer/fogger on for about a year now, I did buy an EFIE or as some call it a fever buster. My voltage for the first ten seconds once I turn the key into the run position is 4.5V, assuming this is the heater voltage spike to get the sensor warmed up, then it drops to 2.6V and hovers their for a few seconds then it starts going crazy from 2.7 - 3.3 V with the car in idle or running at highway speeds. I can't get the voltage to fluxuate one way or another with the EFIE unless I'm in neutral and at idle, then I can mess with the AFR, but once I start driving again, the Voltage starts jumping. I'm rather sure the EFIE won't do the job for these types of sensors since the max voltage range is about .7.

I've tried everything, I saw the post on adjusting AFR's in your tuning guide, I don't claim to be the electronics wizard by an means, but I did go and buy a set of 10 Ohm 1 Watt resistors, and 15 Ohm 1/2 Watt resistors and placed one at a time of course on the computer input wire, thus far I'm not seeing a difference, even though Current is what were trying to manipulate, I just can't seem to get any results with controlling the spastic voltage going into the ECU, thus I have no real control over the Air/Fuel Ratio. I'm not going to complain too much, I'm getting 33.8 MPG on a 4x4 Jeep.

Any info would be great. Thanks
(This post was last modified: 04-24-2008 12:41 PM by Jeephigh_11.)
04-24-2008 12:39 PM
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mike Offline
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Post: #8
RE: AFR or O2
Yes, it sounds like you have an AFR sensor. And yes, an EFIE is not designed to work with them. I see from the other thread you're on, you've found Tuning For Mileage. Other than that, the only other handling I know for AFR sensors are the O2 extenders. You can search for them on ebay. I think they cost about $10. They just move the sensor out of the air stream a bit, and it causes them to read a bit richer. This in turn will get the computer to lean the mix a bit.

If you do the extender, watch out that you have some room to install it, and that you get the correct thread size. Also, I'd be interested in hearing your results, like before and after statistics.

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04-24-2008 07:13 PM
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colchiro Offline
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Post: #9
RE: AFR or O2
Jeep, you may need a special socket to remove your sensor too. Mine has a slot for the sensor wire to exit the socket.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
04-24-2008 07:20 PM
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Jeephigh_11 Offline
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Post: #10
RE: AFR or O2
Thanks guys, I've seen the extenders but always thought that was WAY to easy of a fix, so I never did it, but hey it's only ten bucks, that just about pays for itself in 70 miles for me. I'm going to run with a 1/2 Watt 15-Ohm resistor for a tank and see what I get, then if I can't get any positive results I'll try the extender, and your right, I'm not sure how to get a socket in there to get her out, the O2 connector is a bit to large to make it through the socket hole, let me know where you got the special socket colchiro, and I will post my results, this is the only forum on the net I've found so far that know what an EFIE, Fuel Warmer, and Hydro-Boost are, I can't even get NTK to tell me what type of O2 sensor they put in the Jeep Patriot, and they're the OEM.

This is the only site that probably even cares about the results.........
04-24-2008 07:32 PM
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