sc3boost

i have a 92 sc300 5spd, i had a some problems and i fixed them all thanks to this site but now i'm getting code 28.................................again, i know this is 02 sensor but why would it come back, and also i can only pull the code if i put the ecu into cheak mode, i just bought two new LEXUS o2 sensors for $140 each so i ve been in a bad mood lately.
i've been reading my manuel for two days now and it says that i'm soposed to have 3 02 sensors, 2 up front and one after the cat, problem is i don't have one after the cat is this normal since i have a 1992???

i'm up right now racking my brain trying to figure it out 4:40 am

mteele

iTrader: (5)

https://www.clublexus.com/forums/sho...hreadid=137385

sc3boost

so all sc300's have 3 sensors two on the manifold and one after the cat right.
but mine is a 92 and i looked under the car and it only has two, could it be missing .
i don't know if my symtoms point to the o2 sensor here they are:

bumpy idle
white smoke/fuel smell
hesitation
and it cut off on me twice in two days, then it would'nt start, then it started and cut right off again.
after about two three min it started right up.
and today it's running fine except for the bumpy idle
i have new plugs, wires, cap and rotor, my coolant level is normal.

could a missing rear o2 sensor do this

Dx3

iTrader: (13)

Hey man,

The sub O2 sensor is a code 27. When I redid my exhaust I got the code for a while, but during that time I didn't ever experience any problems.

Sorry I couldn't be of any more help,

Peace,
Jonny

sc3boost

so 28 is the code for the sensors after the cat right.
problem is i don't have one after the cat, should i just but one a put it in with a new bong???
also the 1992 model has post cat 02's right

qtb33

From what I know(which may be wrong) your 92 is OBD I so you shouldn't have a down stream O2. As you have stated you don't. Is it possible you have a ECU from a OBD II car and you now having issues? As you said it is new(to you) so the previous owner may have done this. This would cause many problems and they got rid of the car instead of dealing with them.

Although, I would think there would be more issues thant he down stream O2 sensor. I would take a look under the car carefully and see if there is even a wiring harnes for this. Something is fishy here.

Best of luck

gadgetSC

92 SC300 with California emissions has the third O2 sensor in the second cat. The rest of us in 92 only have 2. This I know for sure.




gadgetSC-t

sc3boost

maybe i do have the wrong ecu, but i would think i would have more problems.
i don't know if this will help, when i changed my exaust it had another cat after the main cat, then two resonators, how can i tell if my car has a cali ecu.
ok on the other hand if may car is OBD1 why would i get code 28, does it mean something else on the 92 models, i have the manuel for a 1992 sc300 and it has code 28 listed as the main o2 sensor, why would a obdI car give a code that a obdII would give.
so the ecu thing sounds plausable, how can i tell if my car came from cali??????????????????