4 wire Oxygen sensor installed

Post by **Legacy777** » Sun Nov 30, 2003 4:47 am

nah.....as long as you used the copper anti-seize compound, you should be fine

123c · Post by **123c** » Sun Nov 30, 2003 5:14 am

Legacy777 wrote:nah.....as long as you used the copper anti-seize compound, you should be fine

Yes, I used that stuff, and I can smell it....

123c · Post by **123c** » Fri Dec 05, 2003 5:34 am

I have one tip to offer, and that is to make sure the connections are nice and tight. I checked things yesterday and I found that a few wires came loose, so I pulled it and redid the connections.

Today I noticed that the car ran horrible, and had very little power, I am trying to figure if this has anything to do with the O2 sensor???

Post by **Legacy777** » Fri Dec 05, 2003 2:49 pm

Yes.....if you use just the crimp connectors......you better crimp the living hell out of them.....or as my stereo friends used to say.... the "colombo crimp" They may not have looked the prettiest....but they weren't going anywhere.

I would probably say the O2 sensor isn't causing your car to run horribly......you sure you hooked the wires up correctly.

You may want to reset the ECU.

123c · Post by **123c** » Sat Dec 06, 2003 1:42 am

I made sure I hooked up the wires correctly on the O2 sensor, and I have already reset the ECU a few times, but I will reset it again. Today it was running a little better. I could also smell some raw gas, but I wasn't sure if it was coming from my car or not...

123c · Post by **123c** » Fri Dec 12, 2003 4:23 am

I have noticed a slightly better mileage now, but I havn't really driven enough yet, just that my needle hasn't been dropping as fast. I will post my results later. I am guessing that I am getting close to 20mpg with all city driving, this is up from the 15mpg that I have been getting...

123c · Post by **123c** » Tue Feb 24, 2004 6:16 pm

After driving my car with the 4 wire O2 sensor for 3 months, I have come to notice a very huge decrease in mileage. I am wondering if I am having problems with the splices staying together or not... On the Mercedes board that I belong too, many people have said that they have had problems with the universal O2 sensors from Walker...

Post by **Legacy777** » Tue Feb 24, 2004 11:43 pm

hmmm.....that's interesting. There anything in particular they said is wrong with the walker units?

I'll have to take a look at the readings coming from mine.

My mileage is pretty consistantly sucky around 21mpg. Try resetting your ECU and see if that changes mileage.

minoru · Post by **minoru** » Sat Mar 13, 2004 1:01 am

Is there any way to burn an oygen sensor just measuring the heater resistence? I just bought a new 3 wire Bosch O2 sensor from a part store...they said is specific for my Legacy. I was courios to see if the heater mesures 30 Ohms...i think...as they say in the Heynes book. As i put my tester on it...it showed 300....and went to 1 again...the tester was on 20 ohms unfortunatelly...I switched it too 200 ohms...and nothing...the heater seamed to be burned...or discontinue.
I just puted in yesterday...so I donno if my mpg got better. Before I was doing 15l/100Km...(sorry for not converting) I hope it will decrease to 10 or smth...I'll let you know.
But I am really courios if it is possible to burn it. I don;t think so...but I need a second opinion. Somebody who knows more electronics than me

Thx

georryan · Post by **georryan** » Sat Mar 13, 2004 7:58 am

So I went to buy a oxygen sensor and it was 127 dollars at Kragen. The one for the N/A is 50 bucks. Is there really ANY difference?? That's highway robbery if its just because mine is a turbo car.

If they are different, can I just use th same one Josh got?

Finally, were is the heater ground wire Josh? Is it near were the stock turbo O2 sensor is located?

-Ryan

ciper · Post by **ciper** » Sat Mar 13, 2004 8:01 am

DO NOT PURCHASE OXYGEN SENSOR TOOL FROM OXYGENSENSORS.COM
I snapped one in half today.

georryan: The turbo one has a shorter cord. So you are paying an extra 77 dollars for LESS wire!

Why are you getting one from kragen?

georryan · Post by **georryan** » Sat Mar 13, 2004 8:08 am

Because I usually they are a cheap auto parts store. I figured they'd get me a good price on an O2 sensor.

I'm still waiting on the price from subaruparts.com

That's the ONLY difference? Shorter cord?? What the heck? They make a shorter cord and charge me up the wazoo because my car says "sports sedan?" What a rip. Ok I'm done now.

How did you break your O2 sensor from oxygensensor.com?? Will they replace it?

edit: Oh, you broke a O2 sensor tool.... what is that by the way? Do you still think that the O2 sensors from there are good?

ciper · Post by **ciper** » Sat Mar 13, 2004 8:13 am

The 02 sensors from them are great.

The tool is something you should always try to use (though on subarus most cant fit). Its basically a socket with a section removed so the wire can pass through. Also most of them have a hexagon top so you can use a wrench to turn them (usually what you do ona subaru)

georryan · Post by **georryan** » Sat Mar 13, 2004 8:18 am

ah gotcha.

So I can use the same part number Josh did to order from them right?

Oh and were is the heater ground wire that Josh used for his sensor?

Would that be a good place for me to ground my fourth wire?

ciper · Post by **ciper** » Sat Mar 13, 2004 8:21 am

Wait, doesnt our sensor already have two wires for the heater and a single for the sensor?

georryan · Post by **georryan** » Sat Mar 13, 2004 8:23 am

I'm confused, one was for the power, one ground and one for the sensor...right?

From skimming over Josh's directions, he took a four wire sensor and connected everything to his old wiring for the old sensor and spliced in the fourth wire ( a ground wire) to the heater's ground. I was wondering were that was.

ciper · Post by **ciper** » Sat Mar 13, 2004 8:30 am

Not from the sensor point of view. From the car side yes.

The heater can be installed either way (doesnt matter) and has two wires, which are power and ground. In fact most of the time the wires for the heater ARE THE SAME COLOR, so its not easy to distinguish them. You will have to match it up with the car side wiring, and be extra careful because you could end up connecting a 12 volt line through the sensor and back into the ECU on a 1 volt input!
The sensor has one wire and is normally grounded through the exhaust with a 3 wire.

I agree with what Josh did. Offhand I cant tell you which wire is the ground.

georryan · Post by **georryan** » Sat Mar 13, 2004 8:35 am

Ok, I'm stupid. I should have just read what he posted instead of skimming. I see what he did and I see why we were confusing each other.

I was thinking for some reason that he spliced his his isolated ground wire into the heater's ground wire on it's harness somehow.

No, what he did was hook the two ground wires together. I got it now.

I'll be ordering one of these this weekend. Between that, the new plugs I got and hopefully a purchase of a diamond coil pack (depending on price) I'm hoping to have this hesitation fixed soon.

123c · Post by **123c** » Wed Dec 29, 2004 7:57 pm

Is anyone having luck with their 4-wire O2 sensor coversion? My mileage has been stuck around what it was shortly after the conversion, it really hasn't decreased or increased, but it's stuck at about 16mpg. I think I am going to go back to a 3 wire sensor, probally a Bosch, since they are the cheapest quality sensor out there...

Post by **Legacy777** » Thu Dec 30, 2004 5:32 pm

I haven't had any issues with mine. Granted I haven't tried going back to the 3-wire to see if it makes any difference.

Do the bosch ones come with the connector all assembled and such?

Let us know if your mileage gets better with the three wire.

gt tankie · Post by **gt tankie** » Tue Jun 21, 2005 7:05 am

I believe if the o2 sensor croaks the ecu runs in open loop mode which gives crap fuel mileage.
Mine, as I have found, has been dead for the last 3 years but the ecu thinks the o2 sensor is fine with no codes coming up.
I just got second hand one(bosch 3 wire oem part) and will fit tonight.
I went for a drive and unplugged it and the engine ran no different which tells me its been open loop for a while.
Ill see how it goes.
BTW if anyone wants to see inside one of these things I can tear the old one apart and take pics for you.

Gary

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