When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So ive been having parasitic draw killing my battery very quickly, come to find my 02 sensors are very warm to touch. So i cut the switched ignition to no avail, still hot after a few days. Why else would they be heating up? Its a 99 or 00 block, harness and pcm.
I will mention i wires everything myself, it runs otherwise except it seems to run rich. I assume this may be the issue for that also, seeing the 02s are hot but the block is cold.
The heating circuit for the o2 sensors are only supposed to be on when they are cold. They are controlled by the PCM. They’re not supposed to be on a switched circuit, they’re supposed to be on their own circuit right from the PCM - nothing else. You’ve probably overheated them and ruined them. Redo your wiring properly and buy new sensors.
Anything that turns something off and on IS a switched circuit, whether it's the PCM or manually done. In this case SOMETHING kept them on and likely burned them out as Lugnut said.
After i got G Atsmas' mssg I went and double checked a diagram i used. So my understanding is this is "ign. on, heated cuircut on" "ign. off, heated cuircut off". However your saying this should be temporarily on, could the ground be switched? Im pretty sure i grounded to chassis or block.
Black is ground and pink is hot which powers the sensors. Purple and tan are the signals coming back from the sensors. You want to look at the power distribution schematic to see if the pink is run through a relay (which I'm pretty sure it is). The relay will only send power to the sensors if it's switched by another sensor (most likely a pcm signal or a temp sensor directly).
The PCM controls almost everything by the grounds. The coils, the injectors, the heater circuits for the O2 sensors - I don't know what that diagram is but the PCM needs to monitor the heater circuits. You should be getting codes with them connected directly to chassis ground.
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.
7 Most Reliable High-Performance Engines GM Has Ever Built
Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
02 problem 
