iggy1991

I've read every now and then about people converting to a 3 wire O2 sensor because they say it works better. What are the pros and cons of doing this mod and does it really work better as far as better performance or just all around.

What about giving a better reading on an air fuel ratio gauge mounted in the car and somewhere I read somethign about wiring it to the harness. I'm guessing its the bundle of wires that comes into the computer.right?

dimented24x7

iTrader: (2)

The three wire O2s everyone referes to are the heated ones. Theyre better for use in headers as they heat up faster and wont get cold and sluggish like a single wire unheated O2 can when its really cold out. IIRC, the similar O2s with four wires are like the three wire O2s but with a dedicated ground for the O2.

Fast355

iTrader: (2)

Go 3 wire because the price isn't too much more. They heat up in less than a minute versus about 5 for a standard sensor. They also last longer because deposits cannot build up on them as easily since they stay hot. All you have to do is supply a power and a ground.

iggy1991

ok so whats the interchange of parts when I'm going to a 3 wire O2. Can I use just any 3 wire O2 or does it have to come from like an 95 camaro or something.

dimented24x7

iTrader: (2)

Theres a specific part number that works the best but I dont have it on me at the moment. Maybe someone can post it?

Fast355

iTrader: (2)

Just ask for on for like a 1993-1994 astro van with the 4.3 cpi. Get the universal and you are set. Has three wires, two white and one black. The black is the signal wire for the ecm. The whites go to the heater either one can be positive or negative.

iggy1991

Well I installed the 3 wire sensor without a problem and installed my air fuel ratio gauge with not to much trouble. The only thing about it is it jumps alot. It will even go blank at certain times and give no reading at all. Is this normal?

Fast355

iTrader: (2)

Yes. It is the ecm doing its thing. It dissapears when coasting right??

iggy1991

Well it kinda goes out when I suddenly gas it and also when I get off the gas quickly. When I'm cruzin it goes between lean and ideal like the red night rider scanner. You said its the ecm doing its thing but I have it wired before the ecm so its only the O2 doing this. Is there another way to wire it up, after the ecm?

Fast355

iTrader: (2)

I say it is the ECM doing it thing because it is. The O2 sensor is providing feedback to the ECM for fuel trim. The ecm is varying the amount of fuel being injected to correspond with this. That makes the O2 sensor voltage change rapidly therefore your LEDs jump randomly. It probably dissappears on the rich side when you gas it and on the lean side when you get off it real quick. Slightly lean is OK for cruise. On mine it jumps around like crazy at all times.

iggy1991

After I read your previous post I understood what was going on and what you ment. It just didn't click right away. At cruize it jumps ideal to lean but at idle and WOT it is at the first rich bar which I guess is pretty good. I'd love to get a wide band O2 on there and see what it really is but this will have to do.
Thanks for the help.