Primary and Secondary 02 sensors?? - Honda Forum / Acura Forum

Johnny Tran · 11-03-2004, 11:51 AM

Can I use my secondary 02 sensor in place of my Primary? I currently am running a p-28 with a high flow cat so i dont have a secondary 02 hooked up. i think my primary 02 may have taken a shit, so can i use the secondary in its place or are they different???

Johnny Tran · 11-03-2004, 03:52 PM

ok im pretty sure you can, from what I read they are the same except for the length of the wire

jon · 11-03-2004, 04:49 PM

you might be able to, but i think they have different part#s

Johnny Tran · 11-03-2004, 05:36 PM

Quote:

Originally Posted by BFK_SI_EG

you might be able to, but i think they have different part#s

Yeah the different part numbers as far as I know are because they have different length wires. I'm 99% sure that they are interchangable.

jon · 11-03-2004, 05:40 PM

Quote:

Originally Posted by Johnny Tran

Yeah the different part numbers as far as I know are because they have different length wires. I'm 99% sure that they are interchangable.

only one way to find out

gurusan · 11-03-2004, 07:58 PM

I can't give you a definite answer...but...

I mean... an o2 sensor is an o2 sensor....they are both narrowband...so...

poo.

NationsMostWanted · 11-04-2004, 08:50 PM

in my emissions class..i believe they are different on most cars. one is to measure before the cat and one is to measure whats coming out.

so im not sure on that one for sure...but if they are different part numbers then theres a reason for it.

97CIVICoupe · 11-05-2004, 12:52 AM

Quote:

Originally Posted by asianpride559

in my emissions class..i believe they are different on most cars. one is to measure before the cat and one is to measure whats coming out.

so im not sure on that one for sure...but if they are different part numbers then theres a reason for it.

Upstream is for fuel trim, downstream is for monitoriing whether or not the catalytic converter is doing it's job.

Johnny Tran · 11-05-2004, 06:41 AM

Ok so will it work or not?? I realize that the two locations play different roles, but is it the location where the 02 is plugged into that makes the difference or is it the actual 02 sensor itself?

isnbrg9 · 11-05-2004, 12:42 PM

i would think they are not interchangeable. i checked out oxygensensors.com and they specify Primary or Secondary.

Link

NationsMostWanted · 11-05-2004, 06:49 PM

Quote:

Originally Posted by 97CIVICoupe

Upstream is for fuel trim, downstream is for monitoriing whether or not the catalytic converter is doing it's job.

so im right?

but the question is will it work. im not positive on that answer if it would work switching them

97CIVICoupe · 11-06-2004, 10:03 PM

Quote:

Originally Posted by asianpride559

so im right?

but the question is will it work. im not positive on that answer if it would work switching them

Right.. the upstream measures the amount of oxygen in your exhaust stream. It doesn't know the exact A/F ratio, but it knows whether or not the car is running rich or lean depending on the voltage it's putting out. The only oxygen sensor that will read the exact A/F ratio is a wideband O2 sensor. Anyway, the upstream can tell whether the car is running rich or lean and sends that info back to the ECU, where changes are made, controlling your fuel injectors' pulse width (how much fuel's being sprayed), in turn trying to get the mixture back to stoichiometric. And yeah, the downstream just measures oxygen levels in the exhaust after the cat to make sure the cat is actually working and reducing the amount of bad emissions coming out the tailpipe.

NationsMostWanted · 11-06-2004, 10:05 PM

Quote:

Originally Posted by 97CIVICoupe

Right.. the upstream measures the amount of oxygen in your exhaust stream. It doesn't know the exact A/F ratio, but it knows whether or not the car is running rich or lean depending on the voltage it's putting out. The only oxygen sensor that will read the exact A/F ratio is a wideband O2 sensor. Anyway, the upstream can tell whether the car is running rich or lean and sends that info back to the ECU, where changes are made, controlling your fuel injectors' pulse width (how much fuel's being sprayed), in turn trying to get the mixture back to stoichiometric. And yeah, the downstream just measures oxygen levels in the exhaust after the cat to make sure the cat is actually working and reducing the amount of bad emissions coming out the tailpipe.

yea i get what ur saying but are they interchangable thats what im wondering?johhny tran saids it not the prob but im wondering if they are the same sensor? even though they measure different things in different spots but are they the same sensor

97CIVICoupe · 11-09-2004, 09:02 AM

Quote:

Originally Posted by asianpride559

yea i get what ur saying but are they interchangable thats what im wondering?johhny tran saids it not the prob but im wondering if they are the same sensor? even though they measure different things in different spots but are they the same sensor

Yeah, an oxygen sensor is an oxygen sensor. Unless the car uses a wideband sensor (which it doesn't) then it's usually the upstream and a regular O2 sensor is used downstream.