Car running better with O2 sensors unplugged?
#1
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I made a thread about some problems I was having before with my car. It was just not running right, the main thing I noticed was when I'd slow down or come to a stop the cars would idle very low and sound like it was going to stall. I tried a lot of different things to help the car but had no luck. I unplugged the O2 sensors just to try something else and I haven't had the problems since.
I was wondering if I should go ahead and just replace the O2 sensors or if this could mean something else.
Thanks in advance for any help.
I was wondering if I should go ahead and just replace the O2 sensors or if this could mean something else.
Thanks in advance for any help.
#12
Staging Lane
Join Date: May 2012
Location: austin, tx
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Get a decent scan tool and check to see what the 02s are doing if they are switching properly and arent getting lazy. I have actually had a engine fail after running it hard for a long period of time with the 02 unplugged it leaned out and melted a piston, it was not a gm so I am sure it is a different system but I would be careful.
#13
TECH Enthusiast
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When everything is plugged up and the car is warmed up, it'll run Closed loop. If you unplug the maf, it still runs closed (accepts input from the O2 sensors), but in speed density mode. If you unplug the O2s, it puts the bank w/ the unplugged sensor into open loop mode. So if you unplug the MAF and plug in the O2s and it runs good, that means you probably have a dirty or bad MAF. Especially if you run a K&N Filter. The oil on those things loves to fck with your MAF. Another possibility is a bad IAT Sensor.
#16
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There are no rear o2's, they have been tuned out. I still haven't had a chance to plug the fronts back in and unplug the MAF. Hopefully I'll have time to do it tonight. Is there some type of test I can do on the oxygen sensors to see if they're bad without a scan tool?
#17
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Strange thing I noticed today, I plugged the o2s back in, I sat in the car and revved it up to 2500 rpm to hold it steady there. It dropped to ~2470 and then after a couple seconds went back up to ~2500 then went back down and back up every few seconds. I've ordered a scantool that should be here in a couple days, but does anyone have any ideas?