Wierd o2's -long

[JiP]

Well I been gettin like 9-14mpg for the past few months, checked everything you can think of everything was fine. Today I decided fuck it ill move shit back to stock and work from there only have 4 mods everything else are looks.

Also I am working on a DIS converter for 7gs, and so I had 99cent bosch plugs sparking under my laptops control in my room, nice bright sparks. Pulled my cars platnium plugs wich are about 2 months old and the sparks were really weak andpathetic. I changed the plugs to planiums 2 months ago to try and solve the low gas mileage..it didnt work. Seeing the spark power difference I decided to put the cheap bosch in the engine gapped at about .040

Put the plugs in, put my stock airbox back in place and drove a good 40 miles and thank god finaly back up to 24mpg.

However my o2 meter is reall funny, at partial throttle crusing speed the meter is just totally blank as if there were no throttle. At very low maybe 10% throttle it bounces like it should. WOT, either comes up totaly lean or blank. Wtf is that?

Mind you im still running the 60mm tb, but with my shortram and K&n o2s were perfectly normal, full throttle I was into rich side, other times it just bounced as it should in closed loop.

So wtf is goin on? Havnt plugged the datalogger in yet to see fuel trims.
Any ideas?

[ken inn]

yup. if your o2 is not bouncing around, it is in open loop, and is running off of factory set fuel maps. this is common, on my car(91 vr4), above 4k rpm, it goes open loop, the o2 gives a steady reading, but the ecu is not reading o2 input. however, at idle, or below 4k, what is happening with your car, is something is so far out of whack, that the o2 sensor cannot correct it, so the ecu gives up and goes open loop. which is usually richer than closed loop. most of the time, it is an air leak-too much air, o2 cannot richen it up enough. solve this problem, your fuel economy will improve even more.

[JiP]

I understand how o2s, closed/open loop work, though I did not know that if the ecu cant correct it it will just dump fuel, but even dumping fuel 02 sensor would still read something open or closed loop and the meter should still show something. And wouldnt that throw an error code anyway?

I am running the 60mm tb, but it doesnt make sense that the ecu would be able to correct fuel conditions for the increased airflow with a K&n but not with the stock airbox. If anything the stock airbox should be giving less air to the system thus making it easier for the ecu to control the mixture.

And I have been gettin 9mpg! with the original setup and o2s working normally...Dont know if it was the plugs or the airfitler but no o2 readings my gas mileage has gone back up to 24mpg.