Heated O2 Sensor
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Heel & Toe
Joined: Mar 2006
Posts: 23
Likes: 0
From: somerset nj
Heated O2 Sensor
I've been lurking around here for a few years absorbing all the great knowledge that is shared. I have an 89, 6-spd L98 with basic DIY mods (headers, freeflow cat + catback, AFPR, ported intake and runners, modified MAF, SLP Cold Air Intake, TPIS chip). My question deals with upgrading to heated O2 sensors. I have been researching the how's and why's and would it be beneficial to install a switch for the "heater" portion of the sensor? Once the sensor reaches the proper temp (600deg or so) and the car runs in closed loop, do I need a heat source still running to the sensor? Won't the sensor burn out quicker due to the constant heat source? From what I understand about newer cars, the heat source to the sensor is controlled by the computer and is turned on and off depending on the sensor temp. Am I crazy for wondering about this?
Thanks to all who have posted excellent info on this site. I read it twice a day and always learn something here.
Thanks to all who have posted excellent info on this site. I read it twice a day and always learn something here.
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Originally Posted by scott89
I've been lurking around here for a few years absorbing all the great knowledge that is shared. I have an 89, 6-spd L98 with basic DIY mods (headers, freeflow cat + catback, AFPR, ported intake and runners, modified MAF, SLP Cold Air Intake, TPIS chip). My question deals with upgrading to heated O2 sensors. I have been researching the how's and why's and would it be beneficial to install a switch for the "heater" portion of the sensor? Once the sensor reaches the proper temp (600deg or so) and the car runs in closed loop, do I need a heat source still running to the sensor? Won't the sensor burn out quicker due to the constant heat source? From what I understand about newer cars, the heat source to the sensor is controlled by the computer and is turned on and off depending on the sensor temp. Am I crazy for wondering about this?
Thanks to all who have posted excellent info on this site. I read it twice a day and always learn something here.
Thanks to all who have posted excellent info on this site. I read it twice a day and always learn something here.
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
The source of the heat is the exhaust.
the 600°F temp can be reached if the O2 sensor is CLOSE to the engine...so in the first portion of the exhaust pipe (as the stock one).
On Headers you have 2 choices:
Example: the hookers headers have the bung on the #7 pipe.
I'ts close enought to the heads so it will stay in closed loop because even at idle it can maintain the 600°F temp.
In this way the O2 read, is the one in the 7 pipe only...
To read a complete bank... you should relocate the the O2 sensor where al 4 pipes meets. At this point we are too far from the engine so it's possible that in Idle and cold climate the car exit from the closed loop. At this point the Heated O2 is required. The simple version of an heated O2 sensor has 3 wires. one for the signal (the same violet wire that the stock O2 sensor attache to..) the ground wire, and the wire that needs to be connected to a 12V switched source.
-Beppe-
the 600°F temp can be reached if the O2 sensor is CLOSE to the engine...so in the first portion of the exhaust pipe (as the stock one).
On Headers you have 2 choices:
Example: the hookers headers have the bung on the #7 pipe.
I'ts close enought to the heads so it will stay in closed loop because even at idle it can maintain the 600°F temp.
In this way the O2 read, is the one in the 7 pipe only...
To read a complete bank... you should relocate the the O2 sensor where al 4 pipes meets. At this point we are too far from the engine so it's possible that in Idle and cold climate the car exit from the closed loop. At this point the Heated O2 is required. The simple version of an heated O2 sensor has 3 wires. one for the signal (the same violet wire that the stock O2 sensor attache to..) the ground wire, and the wire that needs to be connected to a 12V switched source.
-Beppe-
Le Mans Master
Joined: Jul 2001
Posts: 8,183
Likes: 3
From: Santa Maria, CA
Location of the sensor in relation to the exhaust port on the heads makes a difference.
I prefer to have it sample gasses from the bank instead of one cylinder.
Looking at the 89 6 speed car from underneath, it made more sense to me to install the O2 bung on the passenger side collector. More room on that side.
This made it necessary for me to make extensions for the 3 wires. Not too bad. Here's a pic, *note the sensor on the passenger side:
I prefer to have it sample gasses from the bank instead of one cylinder.
Looking at the 89 6 speed car from underneath, it made more sense to me to install the O2 bung on the passenger side collector. More room on that side.
This made it necessary for me to make extensions for the 3 wires. Not too bad. Here's a pic, *note the sensor on the passenger side:
Last edited by pablocruise; Jun 23, 2006 at 12:11 PM.
Team Owner
Joined: Sep 2001
Posts: 62,126
Likes: 1,727
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Heated sensors allow the car to go into closed loop earlier (~450), and prevents it from dropping out of closed loop at idle. Thats the benefit. People with headers could see a big change in their MPG with it, but those without will likely see very little change if any.
You dont disconnect its 12V source during car operation. That isnt regulated by the ECM on your car, it sends signals to the ECM always but they are ignored until all parameters are met and the voltages its sending are within spec.
You dont disconnect its 12V source during car operation. That isnt regulated by the ECM on your car, it sends signals to the ECM always but they are ignored until all parameters are met and the voltages its sending are within spec.
