obd2 ls with 1 02 sensor?

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J

joshpntbl85

New Member
a guy from my work bought a 93 civic with a 97 b18b swap. he said the idle was surging and it had a cel, so i checked to see what codes he was pulling. it was 12 (egr) and 41(primary 02).i have never owned a obd2 car so i dont know much about them but when i look under the car and there is only one 02 sensor. maybe im wrong but i thought obd2 cars use 2 sensors. but i figured the car would run horrible with a missing 02. it runs pretty good though, just a surging idle from the bad egr valve im guessing. what you guys thinking?
 
Sounds like its an obd 2 engine converted to obd 1.

All that had to be done to make it obd 1 is change the iacv, dizzy and alternator. Ya I think that's it.
 
nope, he is running a pr4 obd2 ecu. i talked to a guy that helped with the swap. he is saying that there is supposed to be a 02 sensor before and after the cat converter, but since the car doesnt have a converter, it wouldnt make any difference in how it ran, it would just make the cel stay on. doesnt sound right to me, but again, i have no experience with obd2
 
everything has been converted to obd2. everthing but the wiring of the second 02 sensor. the guys who did the swap just didnt wire it up, because they are saying it doesnt make a difference as far as air/fuel ratios and stuff because he doesnt have a cat converter on the car. just doesnt sound right though and i was wondering if anyone would second that explaination.
 
I think it would probably run better with both sensors in there. I was running without the primary sensor on my 97 Integra for a while because I was having trouble getting it out of the old exhaust manifold when I put my header on. It seemed to me that the gas mileage got worse, but maybe not, I'm no expert.

Plus that CEL is always going to be on as long as the second sensor is missing and he's still using the OBD2 ecu. You can temporarily get rid of it by resetting the car's ECU, but it will come back. I would fix it just for that reason, because if the CEL is always on then he might just assume its from the sensor when other things might be wrong too.
 
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If I were him I'd put the stock wiring harness back on or remove the jumper, convert the engine to obd1 and run it that way. OBD1 is more tuneable anyway. If I had an obd2 car I'd change it to use an obd 1 ecu.
 
yeah he said it was getting pretty bad gas mileage. i read on another site that when you put either the primary or secondary (not sure which one) in you need to use a 02 simulator because the stock cat converter is not on the car or the cel will still stay on. personally i would convert to obd1 because i tune with crome, but this isnt my car. thanks for the help yall
 
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