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dead O2 heater

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jtjerry

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Discussion starter · #1 ·
I think I can have dead O2 heater. :rolleyes:
When engine is hot (1G T 1990) on idle as I look at logger O2 stay standing still at 0 volts. As I start driving it start making fine waves form 0.1 to 0.9. But when car is standing and idle there is no change in O2 voltage. Is that symptom dead O2 heater or that is normal ?

BTW I have MAFT and always have low trim at 120%...
thanks for answers

Jerry, Poland
 
#4 ·
Yea, the heating element is likely dead. Thats what mine did before it died, worked fine normally but if I let the car idle too long it stopped working :(

I replaced the sensor and all was well :)
 
Discussion starter · #6 ·
today I changed o2 sensor (used one too). But it work same as old: change volts from 0.1to 0.9 when off idle. When on idle it stay at one point: 0.0 volt. So looks as second used sensor have dead heater element too. Some one can check that with data logger?
On idle when engine is hot o2 stay at zero or make waves?
Jerry.
 
#8 ·
It should cycle just fine at idle and anything under 4000 rpms and 35% throttle. The heater won't cause that to happen. I know this because I haven't had the heater hooked up on my O2 for eight months now. It will run fine, it just takes a little longer for the exhaust gasses to heat the sensor.
 
#9 ·
im having the same problem and switched out to another used sensor with same results. im wondering if there is any power going to the heater in the o2 sensor? maybe we have wiring issues!

i think i shoudl check for that before i buy a new o2 sensor but im sure a new sensor wouldnt hurt
 
Discussion starter · #11 ·
Today I buy and mount new o2 sensor.
All is as before: at idle there is no change in sensor readings. Always logger show 0.01v at idle.
There is 12v for heater, ground for heater, and all wires are ok.
Maybe that sensor work with OEM restrictive exhaust systems with cats and that all small funny pipes.
I have 3 in exhaust without cats. Maybe gases flow too fast to maintain enough temp on sensor at idle.
After all: all 3 sensors I changed (stock, used one and today new) works same way.
Can someone with big exhaust and data logger check that PERSONALLY?
Looks as all effort and money I spend at that sensor was wasted :mad: :mad: :mad: and that info (sensor work at hot idle) is BS...
Jerry
 
#12 ·
no that is not the case at all, my buddy with 3inch exhaust cycles just fine at idle, i find that if i play with my maft settings i can make it richer until it cycles so maybe no cycle is a condition of lean at idle but that i can live with if its the case, i dont mind the no cycle i just wanna know why thats all
 
Discussion starter · #13 ·
AWDMike said:
no that is not the case at all, my buddy with 3inch exhaust cycles just fine at idle, i find that if i play with my maft settings i can make it richer until it cycles so maybe no cycle is a condition of lean at idle but that i can live with if its the case, i dont mind the no cycle i just wanna know why thats all
Click to expand...
that may be the point!
I have maft and my idle is lean (max compensating on low fuel trim).
I will try add some fuel at idle and see if it start cycles...
thanks for idea
Jerry
 
#15 ·
ok well i thought my o2 was dead but after replacing to today there was no change so i got to thinking...

i jacked my low dial all the way rich and it starts to cycle, trims start to come down, hmmm thats strange...

so i log the car at wot...hmm im hitting 97% duty cycle at only 16 psi with fuel pump rewire

well i narrowed it down to 2 possbile issues for our problems, dieing fuel pump or dead fpr
 
Discussion starter · #17 ·
are you sure that? so for better economy so lean that o2 do not even cycle that is good? but that do not makes poor performance or hurt engine (assme that lean is only on light conndition, at WOT AFR is good).
 
#18 ·
well i do it and i know a couple other people who also do that. Should you do it? its your car, i dont wanna be responsible if you go too lean or something. i'm just saying dont worry if you arent cycling at idle. Maybe a stock car will but i know my mas doesnt see enough air at idle to even idle well. i have to run +10% at 1k just to get it to idle well. Now if i go +50 or so they will start cycling.
 
#19 ·
AWDMike said:
ok well i thought my o2 was dead but after replacing to today there was no change so i got to thinking...

i jacked my low dial all the way rich and it starts to cycle, trims start to come down, hmmm thats strange...

so i log the car at wot...hmm im hitting 97% duty cycle at only 16 psi with fuel pump rewire

well i narrowed it down to 2 possbile issues for our problems, dieing fuel pump or dead fpr
Click to expand...
How rich did you make your car? 50% rich?
 
#20 ·
noreaga0221 said:
Bingo. If you go lean enough, you can get your o2s to not even cycle while cruising on the highway. It makes for great gas mileage.
Click to expand...
How are you making it run lean? You can take out airflow with the afc I guess but eventually the ecu is going to notice its running lean under low throttle crusing conditions and it will bump up the fuel trim to compensate and you haven't really acomplished anything unless you remove enough air to max out the ecu's fuel trim which would be a bad idea...
 
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