02 Sensor voltage erratic
Thread Starter
Pro
Joined: Nov 2005
Posts: 536
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From: Bardstown Kentucky
02 Sensor voltage erratic
This doesn’t have to do with my vette but I thought you guys might help me out. I have a 383 with a TBI in my 94 Blazer. I am tuning it myself. I am using a Moates Autoprom for emulation, burning, and dataloging. Tunerpro is my software. Anyway, while trying to get my BLMs adjusted I notice my 02 sensor volts will go from 800mv spike down to about 40-50mv then back up. If I bring it up off idle it still does it. It seems to affect the way truck is running in that the RPMs will flutter when the voltage drops.
With the engine off, key on, I see about 80mv with spikes up to about 450mv. These spikes happen really fast. The truck has a gutted cat with no exhaust leaks that I am aware of. The sensor is only about 2 months old. I was thinking it could be because the cat was gutted or maybe a bad connection. Any suggestions would be great.
With the engine off, key on, I see about 80mv with spikes up to about 450mv. These spikes happen really fast. The truck has a gutted cat with no exhaust leaks that I am aware of. The sensor is only about 2 months old. I was thinking it could be because the cat was gutted or maybe a bad connection. Any suggestions would be great.
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
In closed loop if the 02 is working correctly it should be all over the place. If it were to be stuck at almost any voltage would be the sign of it not functioning properly.
In open loop it will be wherever it is programed setting, mine is around 450mv (haven't seen it at wot. should be around 830ish). If it were to be at 900 mv. that would be on the end of the scale (rich).
In open loop it will be wherever it is programed setting, mine is around 450mv (haven't seen it at wot. should be around 830ish). If it were to be at 900 mv. that would be on the end of the scale (rich).
Last edited by mseven; Apr 18, 2006 at 10:14 PM.
Drifting
Joined: Mar 2005
Posts: 1,923
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From: GA
The O2 sensor voltage should swing above and below 500mV constantly while in closed loop. the real question here is weather your INT is following the O2 sensor's voltage spikes and drops. If it is, then you have a fuel trim problem...if it is staying pretty steady then then I would say that the O2 sensor is just doing what it is supposed to.
Drifting
Joined: Sep 2003
Posts: 1,483
Likes: 4
From: middle TN
Originally Posted by Morley
the real question here is weather your INT is following the O2 sensor's voltage spikes and drops. If it is, then you have a fuel trim problem
no0b here, sorry...away from my glossary right now
