corvetteracer72

Hi Guys ,

I am about to start to change headers on my 85.
In another thread I was advised to change the 1 wire O2 sensor on my car with a heated O2 sensor because otherwise the car , when idling might go into close loop because of low exhaust temperature .

So here are the questions - Is it ok if the heated sensor will be ON as long as the engine runs ?

Doesn't it burns off after a while ?

Appreciate any input from you , as I am somehow concerned about a possible issue here.

Thank you .

vader86

When you put headers on, the O2 sensor will drop into the car into open loop at idle because the voltage the O2 sends to the ECM will drop below its expected range for closed loop operation, due to the lower exhaust temps inside the pipe. When that happens the ECM runs the car off preset tables and the coolant temps it reads, which ends up being rich. It just kills some of your MPG if youre idling a lot, and if a cat remains on the car then it'll plug it up with soot.

There is no harm in any way to having a heated O2 sensor in there. Its just another wire that comes on when the engine is running. The O2 is always running when the car is running already, its just being ignored.

C5 Diag

Hello my friend !!...I was trolling the C5 forum...I have an '01 and nothing going...we're all fine over there...LOL !!...all OBD2 cars '96 and later require heated O2 sensors so for your '85 it does not...I believe a zirconia O2 sensor requires around 600 degrees F. to operate properly...on mine I don't know what the exact temp at which the PCM will turn the heater circuit off but I know I will go into "closed loop"...ie...my PCM controls my fuel mixture to "stoic" pretty fast... I'd say less than 1 minute. I'm pretty sure the temp of the exhaust gases exiting your headers is above 600 degrees or close to it...I have a stock exhaust. Now I'm thinking that if your car did not have a heated O2 sensor how will you connect those 2 wires to your PCM ??...There is a transistor (driver) in the PCM that accomplishes this. I don't know where the manufacturer of your headers installs the bung where the upstream O2 sensor would go but it should be pretty close to the collector. Hope this shines some light on the subject !!...and by the way the engine stays in "open loop" when first started (cold engine...low coolant temp), W.O.T., heavy accel or decell, or if the PCM detects a fixed rich or lean signal it goes into open loop...have a great weekend !!

p.s. When I get home later I'll see what my infrared gun shows my exhaust temp as being !!

corvetteracer72

Actually my car has only one wire that goes in the ECM . I am about to buy a heated sensor retrofit kit which has a adaptor harness .
It seems pretty easy to install so I think I can do it .
I was only concerned about the fact that , usually to these sensors after the engine heats up the heater element of the sensor it's being shut off by the PCM . On my car, if I connect the heater element to ignition it will be heated all the time when the engine is on so it may burn or self distruct because of that

C5 Diag

Yes, your O2 sensor has only one wire (the sensor producing its own voltage which goes to the ECM/PCM)...I don't really know about these retrofit "kits"...I try to stay away from stuff like this...sometimes they are more trouble than they are worth down the road when you try to integrate it into factory components. I'd ask the maker of the retrofit if it will definitely work on your car. GOOD LUCK !!

vader86

No. Do not worry about this.

dizwiz24

aklim

As long as you know what year car the sensor fits, all you have to do is ask for that one. That or you keep track of the sensor part number and buy that one again.

You don't connect it to the ignition. Connect it to something worthless like the evap canister or the AIR system. Those are hot when the key is in run mode and cold when the key is out.