I need a set of 3 wire heated o2's and i have heard bad things about bosch so i want to get acdelco, who sells them the cheapest? I can get the 3 wire bosch for like $30 a pice or sumthin.

 

You need 4-wire O2s.

http://samtaylor.com has the AC Delco O2s for cheapest.

 

why do i need 4 wire?

 

Stock O2 sensors are four wire.

 

Aren't 93's single wire? I did hear you have to convert to the 4 wire type since that's the only way they come for the heated 02's.

 

i do have single wire.. i was just going to convert to the 3 wire cause i figured it would be easyier to wire up. I have no clue what i would do with the 4th wire.. I figured on teh 3 wire set up there was a siganl wire for the ecm, a ground, and a positive that would normally be controled by the ecm, but i was just going to wire it up another way.. if someone tells me how to run the 4 wire i will.

 

I didn't even see what year you had.

4-wire O2s are heated, so that's what the fourth wire is for. I wish I could tell you how to hook them up though...

 

Why do you think you need to switch from stock? How are 3 wire O2 sensors better?

 

On 93's you're supposed to get better O2 readings with heated O2's. I don't know why. Lots of people here with 93's run standard 02's without any problems. Wouldn't a chip reprogram be easier and solve any lean/rich problems that might occur with regular O2's?

 

I retro fitted my built 90 454SS truck with a heated (three wire) O2 sensor instead of the single wire one that came oem. I'm told the heated version will go into closed loop quicker and be more accruate if you have headers and a custom exhaust (as I do) and the sensor rides further back from the headers. I'm told that a "cold" running sensor tends to read leaner.

Lastly, the three wires are one sensor signal, second is switched power, and the third is ground.

 

I bought some AC's from Advanced for like $35, they was cheaper than the BOSH....

 

Got mine from Jason Cromer for the same price...

 

I was the first person here (to my knowledge) to try them because it looked like my stock, single wire sensors were not getting warm enough with my Hooker LT's. since they were 4-5x farther away from the engine vs stock.

I came to this conclusion after observing that my BLM values were very erratic and the car would drop out of closed loop at stoplights. Apparently now everyone is recommending heated O2's on 93's without any testing since they 'assume' it will be a problem. So basically people are trying to patch issure they're not even sure they have just because some people on the internet say so.

With stock maifolds or shorty headers I doubt this would ever be a problem.

FWIW 3 wires O2 sensors are heated, just as 4 wire ones are. I have no clue what the 4th wire in the 4 wire sensors are for and no one has been able to give me a reasonable answer. As far as I can tell they work fine without the 4th wire so I can only assume they're for some sort of diagnostic function on some vehicles.

 

I had the same problem with the car droping out of closed loop at stoplights with groty long tubes and true dual 3". And for my car open loop is a big big no no. when i drop out of closed loop the car dies it runs so rich, thanks to the wonderfuly large cam with next to no vacuum at idle. But when in closed loop it will idle fine and everything, so i am trying to get it to stay in closed loop as much as possible, and for me that mean heated o2's. Also how can i get ahold of jason cromer?

 

Stock O2's(single wire) for stock manifolds (exhaust),3 or 4 wire for headers.Previous posts have suggested that the headers don't get hot enough to send signals to the computer for the rich lean thing.My02