I've got a air/fuel ratio gauge in the car and when I let off the gas the light jumps extremely rich then goes right back down.

Anyone else's do this?

Also, is it just because of the old style O2 sensor that it reads really rich when I'm on the gas? My exhaust isnt heavy at all.

 

when you're "on it" the computer goes into PE (Power enrich) mode and richens the mixture to around a 12.5 AFR.


when you are letting off the gas and it goes rich is just the few milliseconds it takes the computer to bring down the Injector pulse width to match the ammount of airflow.

all completely normal.

 

^^^Agreed. When the throttle plate closes, there is a lot more fuel than air going into the engine. Also if you are pulling the signal from the stock NB, it's probably jumping around erratically, right? If you spring for a WBo2, then the controllers will have ouputs that are programable and can send signal every .x seconds (I like .3) and makes the guage easier to read. This NB guage should only be used for referance, since they are inaccurate.

Why did you need an AFR guage? Is somebody thinking of boost?

 

Well, my cars been givin me some trouble with idle and all, we haven't been able to figure it out yet.

So I figured I'd have some fun and install a gauge and I'd also be able to easily see if I was running rich.
A turbo would be awesome, but definitly something for the future when I'm out of highschool. I'd love to have one now, but too much money/time with the car down.

Since the 02 sensor IS pretty inaccurate, I don't really think its worth much on the problem solving side. It does tell me if I'm rich/lean, but other than that....

I'd get a newer 02 sensor, but I can't get the one in there out for the life of me. It's probably the original one from 86. Shop wants $100 to put in a new 5" section of pipe with a bung on it. No way.
If I could get my hands on a welder, I can do it myself - thanks to highschool metal shop - they closed it this year, too, last one in Florida at a public school - gone.

 

Use some PBBlaster. Spay it on heavy and let soak, then usa a 7/8's box end wrench to get it out. If you are real careful not to burn yourself, do it after it warms up.