I have an 02 civic ex boosted(OBD2 Duh) and My car was too low and I ripped the wires off for the primary 02 sensor. Well the car ran fine even without it. Im using a greddy emenage for fuel system. I took it out to the dyno last week without the sensor wired up and the fuel was reading down in to the 9:1 range and 10:1. I just replaced the Primary sensor last night. So my question is, when the primary sensor was ripped out the car would have gone into open loop, but would that cause the Stock ecu to dump more fuel on top of the tune that was set in the emenage or would the emenage just override what the ecu was telling it and only go by the emenage fuel settings? and is it true that whenever you have a CEL on OBD2 that it sends your car inot open loop no matter what the cause? thanks for the help.

 

The cause for the fuel being so rich, was that part of the map was never tuned with the emanage. It was always done by 02 sensor. Now if you WOT was that rich when it was previously tuned, maybe it has to do with fuel trims.

 

when the car was tuned I had an exdhaust leak at the end of the tunning so we couldn't get accurate readings. But I was told it was run at 11:1 but im not positive. Here is the dyno sheet.

 

could also have something to do with a weather change and missing your o2.

 

weather was about the same as when it was tuned.

 

bump for some more info