O2 MV's dropping
06-18-2003, 06:00 PM
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O2 MV's dropping
I looked back at a DM logged full throttle pass and noticed that at each point where I shifted the RPM drops a bit but the O2 millivolts drop substantially. They are in the lower to mid 800 range and then as the RPMs dip, the O2's drop down to about 100 or so. They then pick right back up to 800 range and do it again on the 2 to 3 shift. Is this normal? I am not getting any retard or anything and the car doesn't seem to quit pulling any.
Last edited by justme; 06-18-2003 at 06:10 PM.
06-19-2003, 07:17 AM
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Car: 2005 Subaru STI
Engine: 153ci of Turbo Power!
Transmission: 6-Speed
As long as you are not powershifting then it's normal. Once you take your foot off the gas (i.e. shifting) and the TPS% drops down then the O2 is going to follow (this comment is in relation to the circumstance that you just described).
Tim
Tim
06-19-2003, 09:48 AM
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I notice that the 200r4 in my car tends to do the same. Inbetween shifts(not letting off the gas) the AFR will drop a point or so, say from 11 to 11.5 or even 12 until the shift has been completed.
I just assumed that the load of the transmission shifting was using the extra gas?
I just assumed that the load of the transmission shifting was using the extra gas?
06-19-2003, 11:19 AM
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Car: An Ol Buick
Engine: Vsick
Transmission: Janis Tranny Yank Converter
Re: O2 MV's dropping
Originally posted by justme
I looked back at a DM logged full throttle pass and noticed that at each point where I shifted the RPM drops a bit but the O2 millivolts drop substantially. They are in the lower to mid 800 range and then as the RPMs dip, the O2's drop down to about 100 or so. They then pick right back up to 800 range and do it again on the 2 to 3 shift. Is this normal? I am not getting any retard or anything and the car doesn't seem to quit pulling any.
I looked back at a DM logged full throttle pass and noticed that at each point where I shifted the RPM drops a bit but the O2 millivolts drop substantially. They are in the lower to mid 800 range and then as the RPMs dip, the O2's drop down to about 100 or so. They then pick right back up to 800 range and do it again on the 2 to 3 shift. Is this normal? I am not getting any retard or anything and the car doesn't seem to quit pulling any.
Plus there is a huge reduction in exhaust gas as the engine drops in rpm during the change, so there is also a backpressure change, another thing the oem O2 fall prey to.
Some cars worse the others, yada yada.
