I have a 99 Civic SI. the guy who had it before me got rid of the 2nd 02 sensor. and the car is running in LIMP mode. the cel is on, its for the 2nd 02 sendor, but i didnt know if thats why its in LIMP mode or if it would be something else.

 

bump

 

Yup, you'll be in limp mode.

 

hehe dude.I had a P2t ECU since September when i bought my 99 SI.Drove it first off with 87 gas=Detonation really bad.Past few months been running 92 only even if gas prices are really high.But any way i took the car to an exhaust shop to have them take off the silencer on a Greddy Evo2 Exhaust and they said you know you have no secondary 02 Sensor, and i was like oh really it has a straight cat on it with CEL light.So went home checked the light and of course bright as can be.So i talk to a friend he got me a chiped P06 tuned with chrome and running a CTR basemap.I tell ya not having that secondary 02 Sensor with a stock ECU made the car run like literly ****.Got the new ECU today and car runs sooo much better.Might want to get another 02 sensor or a conversion harness and new chipped ECU like i did.

 

no it will not put it into limp mode. Idk about running like crap either. Two of my cars do not have secondary o2 sensors. 96 hatch with a b16 swap with a p30 ecu, runs fine, just has the cel for the sensor. Same goes for my 98 single cam.

 

i have a header that wont let me have 2 o2's so i left the o2 on the harness just ziptied it to a not hot area on the car and it runs fine with no cel