CEL right after new plugs.

[Colorado KID]

Alright guys. So i've been looking around at some of the threads on the P0170 CEL and almost everyone assumes it is the O2 sensor. Here's my dilemma. I recently replaced the turbo with a FP Big T28 and a 1g Bov since the T25 went bad and i was blowing oil from the bad turbo.. After cleaning it all up, inter cooler and everything, i reinstalled everything. It ran fine except when i went WOT it lagged.. So i checked my plugs and man were they bad. Almost all of them were gapped at roughly .05.. I bought some NGK's and gapped them at .032 like my book says. It ran great for about 4 days without a CEL. No lagging on acceleration or anything. 4 days later.. CEL came on. Since i got the car, I've felt like it has been running rich. Exhaust smelt more thick compared to any other car of mine. More recently i have had black soot on the back of the car above the tail pipe. Old plugs were pretty fouled.. And some days there is a very strong gas smell outside the car after i shut it off.

Anyone believe that this is an O2 sensor still? Or could it be something else?

I don't have a data logger and i cannot afford one right now. Anyway for me to check these things fairly easy? I would assume that i would have gotten a code for the O2 sensor being bad if it was the O2.. but maybe i am wrong?

 

[eeeewidner]

Check all vacuum lines and do a boost leak test and check your exhaust before the turbo. If all is ok. Then more than likely it's the front 02 sensor...

 

[crazyquik22023]

i would say it is most likely front o2... i've had 3 eclipses 2 2g's and 1 3g that have all had this code and it was an o2 sensor everytime

 

[spyderturbo007]

Dying / dead front O2 sensors report a voltage <0.5v to the ECU. This indicates a false lean condition, which the ECU tries to compensate for by increasing the ST and LTFT's. So, yes, a rich condition does point towards a dying front O2 sensor.

Do you have access to a logger so you can check the voltage? If not, you can probe the pinout at the ECU for the front O2 with a volt meter. It should be oscillating between 0.2 - 0.8v at idle when fully warmed up.