Howdy,


Hey, does anyone have an air/fuel guage on they're 360?

mine starts up ritch as hell. which is fine, but after a while it just bounces back and fourth like clockwork...

I'm having problems with pinging like most of you know from my other posts... lol


Would this indicate computer confusion of some sort?

 

Sounds like your running your a/f meter on your stock o2 sensor, not a new wide band sensor, correct? If so, then what you are seeing is normal. That is what is known as closed loop dither. During closed loop operations (idle and cruising rpm for example), you're in closed loop mode, and the PCM is having to constantly make adjustments to A/F based on readings it is getting from the down stream sensors, hence why it dithers back and forth from lean to rich. You want to see a dither rate of about 1 second for each dither (up or down), and the mid point of your dither should be close to the stochiometric point of 14.7:1 (the ideal air fuel ratio). If your dithering consistantly below that, then you are running too rich, and a dither consistantly above that is running to lean.

During cold start up, or when you get on the throttle, you're going into open loop mode. This is when the PCM uses its pre-programmed settings to basically lock into a set a/f ratio. Usually rich so that you can accelerate hard, or for extra fuel during startup.

 

Yessir,

It is the stock o2, its a new one but stock...

well i guess thats good that its normal... I was almost hoping it indicated a problem so that I could get a lead on where to take this investigation...

tommorow I'll floor it and see if it gets lean during some pinging...

thanks for the info