O2 Question

Dirtbuster1

Dirtbuster1

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May 13, 2008
Messages
649
Location
Georgia
Why would a heated O2 sensor cause the ECM to go into closed loop, & a nonheated O2 sensor not? The nonheated is at .5V & the heated is at .9V. The only difference is a ground. I checked the nonheated & it is getting a ground. The heated O2 is screwing with my BLM & TPS counts?
 
.9V is not a good signal, it's a very rich signal

The scale is logharithmic and only sort of liner in the center section, that's where the sensor should operate (.25 to .75V roughly)

nbsensor.jpg

How are you measuring this voltage? Keep in mind that your regular multimeter does not even react fast enough to give a proper votlage, it's a root mean square (average) of the actual sine wave like signal.

What is your BLM showing? .9V may indicate a bad sensor. You didn't by any chance do an ohm measurement across the senor to check for a ground did you? If so, chances are you ruined the sensor.
 
I was measuring the voltage with WINALDL. I did check the outside of the nonheated to see if it was going to ground. The 3 wire sensor should be 12V, O2 ECM wire, & ground I hope. There where not any instructions in the box.
 
I had the same problem, installed a heated o2 sensor and it crapped out real quick, in about a week. Installed the stock sensor and it worked fine. wbo2 with the ebl flash set up is what I did from there, lots of tuning and learning. Let me know if you're looking at tuning soon, I'll be selling my set up since I'm going a different route with my build as you know and won't be using it. Good luck!
 
hmmm this is a interesting thread. I seem to be having O2 problems (I think) after I got the car running again.

I installed a heated (ZR-1) O2 and it really seems to act funny. At idol it is usually sitting a 0.00 (using scan tool) with it going to 0.75 and then decreasing rapid from there back to 0.00. I installed a Rich / Lean gauge last week and driving it is seeing something because the gauge reads where is should however every few minutes it will drop off the scale on the low end and not even read on the gauge indicating it went back to 0.00.

I was not aware there was voltage difference in teh heated and non heated (learned something today). Maybe I should just go back with the single wire and see how it works. I put the heated O2 in because I was afraid the exhaust was not getting hot enough for the single wire to work.

Thanks for this info
Phil
 
No no no, the voltages are supposed to read the same whether they are 3 wire or one wire sensors. The only difference is that the 3 wire has power going to it. The computer would be all messed up if the sensor actually read differently. What I was saying is that my sensor read full rich as well (.9) on the laptop, indicating that it died. I then installed the stock sensor and all was well again. Sorry to confuse you if I did.
 
OH my mistake. I went back and read it again and I understand what you was saying. I must have just read it too fast the first time. :tomato:

Well back to square 1 to try and figure this damn thing out. :banghead:
 
Correct, the readings should be identical....wether heated or not....

the black wires to to the same spot, heated or not...that is the computer input....if it's a 3 wire sensor, you have two white wires and a black....the ground for the O2 crystal is the exhaust system which obviously is the same as engine ground, or better be, damnit....what you need is to make sure the bolt is in fact grounded....don't sound like it from what has been said above....

second off, the two white wires, one goes to ground, I have never seen a sensor that made any differance as to WHICH wire goes to ground in that heater....i'ts just a resistance coil to heat the damn thing up while it's in the header collector, which believe it or not will NOT RUN at 600F, unless it's on the freeway, even in freeking Florida summers....comes outta the engine at 1200f + and cools THAT fast....oh well, chemistry be weird......

so pick one and ground it up top hear the intake manifold, and then find a switched +12 to put the other heater wire to....I used the fuel pump wire....
ignition pink to HEI would work too....

the O2 sensor I used goes to a Chrysler, talk about compatibility, it's a Bosch # 13190 that is got a Auto zone.....I chose it simply because it had nice long leads on it to get that connectors up high on the firewall away from the heat.....

:clobbered::amazed:
 
mrvette said:
Correct, the readings should be identical....wether heated or not....

the black wires to to the same spot, heated or not...that is the computer input....if it's a 3 wire sensor, you have two white wires and a black....the ground for the O2 crystal is the exhaust system which obviously is the same as engine ground, or better be, damnit....what you need is to make sure the bolt is in fact grounded....don't sound like it from what has been said above....

second off, the two white wires, one goes to ground, I have never seen a sensor that made any differance as to WHICH wire goes to ground in that heater....i'ts just a resistance coil to heat the damn thing up while it's in the header collector, which believe it or not will NOT RUN at 600F, unless it's on the freeway, even in freeking Florida summers....comes outta the engine at 1200f + and cools THAT fast....oh well, chemistry be weird......

so pick one and ground it up top hear the intake manifold, and then find a switched +12 to put the other heater wire to....I used the fuel pump wire....
ignition pink to HEI would work too....

the O2 sensor I used goes to a Chrysler, talk about compatibility, it's a Bosch # 13190 that is got a Auto zone.....I chose it simply because it had nice long leads on it to get that connectors up high on the firewall away from the heat.....

:clobbered::amazed:
Click to expand...

I am already running a heated O2 (91 ZR-1) and last year with the old motor I had 0 problems. After i got the new motor in this year it is reading 0.00 most of the time unless it is under hard throttle. Even driving down the road it drops to 0.00 every few minutes. When the car is cold (open loop) it pretty much stays at 0 until the motor is atleast 150 deg. then it will start reading a little. I also notice the car is waaaay rich when cold. It smells like a 67 BB carb car.

thanks
Phil
 
Thats wierd that it would read zeros and be rich. I don't get it. I guess I might double check the wiring for high resistance on the ground or something causing off readings. Maybe a little corrosion in the splices or connectors whichever is on your setup.
 
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