Why are my front o2 sensors dying??!?

[Talonious]

Well, in a previous thread I stated that my car was running very rich at idle and cruise. I would see around 13.6 at idle and sometimes as low as 12.4 while cruising.

A simple log showed my front o2 sensor was NOT cycling correctly. Ok, so I went to Advanced Auto and bought a OE fit Bosch 4-wire and it had the length and connector all their so it was a simple replacement.

Drove around for a day at 14.7 idle, 15.2 cruise. Then out of nowhere after 5-10 mins of driving I look at the wideband and it's showing 13.4 while cruising. Logged the car and of course it's not working anymore.

Replaced the sensor with warranty, Drove around for another day at perfect trims, and then out of nowhere again, my car is idling at 13.4 and idling at 1100 rpms, and crusing at 12.6...???!

I have been trying to combat this issue with this car ever since I bought it.

I have a 6-bolt/7-bolt head motor, small 16g, Punishment Intercooler, Wally 190, 1G CAS, punishment open dump o2, punishment DP, Thermal RD cat-back and everything else including motor is either stock, or rebuilt with OEM parts.

Boost leaked tested at 25psi held strong
Replaced coolant temp sensor and switch with OEM
TPS was set, while setting base timing at 5* BTDC. Biss was also set at this time.
Car idles normal at 8* timing which FSM states is normal.
Coolant temp at idle in my logs was @ 190

Before I replaced the o2 i threw a bank 1 fuel trim malfunction and an IAC malfunction.

I thought my fpr was being over-run but being that a new o2 sensor fixed my car for 20 mins that's out of question.

Whats causing my car to kill these o2 sensors?? Is my Ecu going out, or do i need a grounding strap on my exhaust that I dont have atm...

After the o2 sensor was replaced my idle was 750 rpms, and idle was at 14.7 according to the AEM Uego which is exactly 36" downstream, now my idle is back where I started at 800, jumping slowly while parked to 1100, and idle afr is 13.4/ cruise is 12.4, and my scanner shows my o2 voltage is nothing.

If anyone has any ideas, feel free!

 

[Colt4G63 also]

That's a strange one. I would go back to the basics; check both grounds to the O2 sensor, check continuity on the signal wire, and check that you're getting 12 volts with decent current to O2 sensor heater. As a quick check I usually plug a halogen bulb into the O2 sensor heater circut wires and see if it lights up brightly.

Ps. I reccomend an OE fit sensor because if you wire one of those universal jobbies wrong it's bad news, and it's impossible create a heat proof insulation around the wire splices. Tape or heat shrink tubing just isn't as good.

 

[Tanro]

O2 Sensors will either due because you are running rich, running high egt's, or a defect in the sensor.

 

[LiquidX]

I would check the wiring at the harness to be honest and see what kind of power is being sent to it. I wouldn't be too concerned about higher temps as you shouldn't be hitting the temps that would kill the sensor.

So it was a stock OEM sensor and then an OE replacement sensor that died? Has there been another one? How long of a time period after you bought the sensor has passed since it went out. If not too long I would take it back to the store and say it died on you and get a new one.

 

[BigBeans]

If anyone has any ideas, feel free!

Post a log. It might hold some clues.

O2 sensor wiring is a problem area on these cars. Take a good look at the pig tail on your harness to make sure all the connections are firm, wires are good, contact points are clean, etc.

Edit: these guys beat me to it

 

[Talonious]

Thanks for the replies, I bought the car with a dead o2 sensor apparently because the first time I logged this car I had a no 02 sensor voltage on the scanner.

I then purchased a 4-wire OE fit Bosch that clipped in very easily, I cleaned out both harness clips with duster spray and made sur there was no water in the connections. (both connectors look great.)
Drove around for a day with perfect trims, 14.7 idle, 15.2 cruise. Scanned it again with my snapon scanner and It showed my o2 voltage cycling up and down at idle from .2-.7 or something close to that.

Then that same night my wideband started showing 12.6 cruising and 13.4 idle, just like It did before I replaced anything..Took a log and there was no o2 voltage again.

Went to Advanced and got another 02 sensor, same one. That one only lasted about 20 mins of light driving. I was just doing a half throttle pull in 3rd and when I came to the light, my idle sat at 14.7, and slowly declined to 13.4..and thats the second new o2 ive put in this thing.

Heres a log of how my car was before swapping the o2, this is with the stock bad one in.

O2 Sensors will either due because you are running rich, running high egt's, or a defect in the sensor.

Well, I wasn't running rich with the new sensors 'at first'. My exhaust manfifold was not glowing after the drive. This is the second sensor in 2 days I have swapped in.

Could 'not' having the exhaust grounding strap (like these cars come stock with) do something to the o2 sensor? or what kind of issues could arise if my ECU sensor ground was blown?