Thread: How Many o2 Sensors?

Hey all, long time no post. Everything has been going good. Still have the 02' GP GT Coupe with no issues ever since Bill did the lower intake on it. She still runs great. Just curious.....how many total oxygen sensors do you have on the 3800 Series II? I still have that pesty 0420 code popping up from time to time. I have changed what I thought were the only two sensors, one upstream and one downstream. My buddy is telling me that it has 4 oxygen sensors. I'm just curious. Hope everyone had a very happy new year! Billy

Originally Posted by Fivefingerdeathpunch

You only have 2 sensors. One before and one after the cat.

You'd only have 4 sensors if these cars had two cat converters.

Likely the converter is going away on you and thus the codes you see.

Thanks! I remember when I purchased the car, the kid had told me that he had changed the CAT with an aftermarket one. I was hoping it wasn't that but now that I have two brand new AC Delco sensors in place and still dropping this code, I bet I will have to change it out myself with a new unit.

Originally Posted by Fivefingerdeathpunch

Other option is space the rear o2 sensor out of the exhaust stream some, that way it has a less chance at tripping the code.

It's a cheap fix if it work, I'd try it if it was me.

I've heard of that. I would need to find a spacer to fit. Shouldn't be that hard. Thanks for the suggestion.

Originally Posted by Scottydoggs

Thanks Scotty! I hope all has been well with you and the family. Wishing you a great new year. Hey, would you know what MM our sensors are? I see the Non-fowlers on Amazon but they have different measurements. The one that seems to come up a lot is the 18mm one. I may have to remove one of my sensors and measure it with a caliper. Thanks for the video. I remember reading something about these spacers here on the site a while ago.

search yt, theres vids with the box and part # for them things.

Originally Posted by Scottydoggs

search yt, theres vids with the box and part # for them things.

Thanks Scott. Have a great weekend!

you too.

Spacers came in the mail finally. I'm assuming that I install it in the downstream sensor past the Cat? Already drilled it out. Just have to install and hope for the best.

yes the one near the cat back flange just past the cat.

Originally Posted by Scottydoggs

yes the one near the cat back flange just past the cat.

Thanks again Scotty! I'll let you know how it goes. Bringing it in Thursday for inspection.

A big thanks to you Scotty! Took the car in yesterday for inspection and it passed with flying colors. That non-fouler worked like a charm. No CEL whatsoever and it's been a few days since installed. Thanks again for the help. First year since owning the car that I didn't have to pay extra to get it inspected. $37 bucks and I was on my way! Have a great weekend.

Glad it worked
it amazes me that this method seemed to skip an entire generation here. It's so cheap and simple - why would anyone buy those expensive simulators lol?

Originally Posted by CrazyGuy03

Glad it worked
it amazes me that this method seemed to skip an entire generation here. It's so cheap and simple - why would anyone buy those expensive simulators lol?

I actually saw those things online to buy. I guess if I were going to delete the CAT entirely it would be worth getting one of those units.

in that case a tune would be better all around even if na........

On my 99 mits I went headers and resonator for a cat. The rear o2 is still far enough out of the exhaust stream to pass without a code

01-03 you cant get away with that so easy. it really uses the o2. pcm does that dumb cat test. then over fuels if the light comes on.

Pfffft I know that
but speaking in general, you dhp guys have it easy for the cat test delete


ya my 03 I tuned it out ONLY after Eddie took my HPT file and converted it and disabled the test and sent it back. What a great guy he is - super helpful.

ive had more then one pcm in hand to just do the cat delete and send it back for hp guys.

Well I'll take you up on that should I need to re do my bin again.
This was way before I knew you tho. Wish you were posting back then. Would have been a heck of a lot easier