I went and installed my O2 sensor today. The muffler guys wouldn't put the sensor in the manifold because they said it would definitely crack the weld eventually because of the heat. So they put it just aft of the flang before the first cat. They mounted it horizontal facing the tranny so it's easy for me to access.

I am in the works of installing a digital readout in the dash, for now I am using my multimeter in the car while I drive.

It works great, that's all I have to say. At cruise, it runs at about 750 to 850 mvolts, which is the upper end of my stoich, but still ok. I read that a lot of carbs tend to cruise at about 800.

The sensor immediately told me whats wrong with my idle. At idle, it dropped down to about 50 mv, or extremely lean. I removed the gas cap and richer solenoid connector and adjusted the carb. I kept adjusting the idle screw until it was 750 rpm's. Then I adjusted up the mixture until I got about 800mv. Then I readjusted the idle. It took about 5 cycles to dial it in.

So now the car runs like glass at 750 with a mixture of 800mvolts. Which is just on the rich side but not too much.

With the choke out, it runs about 950 to 1000 mv, or way out of stoich.

Typically, you'll want your reading to be 400mv. I am not sure if this is reasonable for 7's or carbs, considering there are two cats aft of the sensor burning up those HC's.

What I am going to do next, is take it to a smog shop and give them a few bucks to run the rpms's for me.

I'll record my emissions and O2 sensor readings for idle, 1000, 2000, 3000 and 4000 rpms. Any more will be rich anyways, I assume.

Then I'll have be able to tell what the O2 sensor should read to predict what's coming out the back. I.e, a reading of 750mvolts is say .10 CO's, providig the cats are working.

That way I can dial the car in for smog and then dial it back out again for driving. It's too bad I don't mess with jetting or I could have some fun now.

 

Sounds cool man. Im hoping to have one installed sometime in my header so I can do some stuff similar to you. I just didnt wanna do it when it was new because, well because it was new, lol . Anyway, keep us posted.

~T.J.

 

I want to do that.. but I have the street port exhuast meaning two sensors, two gauges, and $.... sounds pretty cool.

matt

 

As soon as I find a camera I'll take some pictures, I mounted my home made digital meter in the dash. I think it's cool though, all though a little bright at night.

You don't need 2 guages. Just use two $24.00 bosch universal sensors. Then get 1 guage for like 50 bucks. Then put a toggle switch to go between them. WIth labor maybe 150 bucks max.

 

Hi !
Would love to see pictures of that!
I'm going to make a ultra small LED based meter to put in my car (and maybe sell a few if it turns out really good).

//Magnus

 

I'll put some up as soon as I find my camera. The one thing that limited my placement was the regulator. You have to use a display that will work off a common ground. All the cheap 6 dollar displays all require a seperate ground. Then I had to sink from 12v to 5 volt, so I have this annoying regulator and sink sticking out from the meter. All in all, the parts cost me 22 bucks.