Homer

iTrader: (1)

Got some questions about how computer quadrajets work. What is the significance of the setting on the mixture stops? If the oxygen sensor, tps, coolant temp, etc sensors provide feedback to the computer to set the proper A/F ratio, what do the mixture stops do?

It seems to me that the mixture stops provide the range of ratios the computer can pick from, and the sensors tell it which way to adjust the ratio to get the right mix. If this is the case, then why wouldn't it be advantageous to set the mixture screws the farthest apart possible to give the computer the widest range of A/F choices available? The sensors will continue to keep the A/F appropriate, won't it? Who can tell me how this computer works?

Thanks,
Homer

P.S. Under WOT, does the computer ignore the sensor and go full rich?

Momar

I dont totaly understand the primaries myself yet so I will leave that to someone else. As far as WOT, the secondarys do most of that. They are so big that the primary fuel ratio doesnt make a big difference. You can adjust this by simply changing rods and hangers.

Ben

Homer

iTrader: (1)

Yeah, I know the secondaries are completely mechanical,

This carb kind of frustrates me because adjusting it is pretty much black magic to me. I've read about how carburetion works, I have a shop manual, I've read that. The measurements and adjustments they tell you to make just don't seem to have any logic behind them. The shop manual does a fine job of explaining what to do, I just don't understand the why.

I guess that's why no one likes the computer quadrajet. You have the technogeeks with efi that can tune every aspect of their car with a computer, and the wrench turning do-it-yourselfer who and can tune every aspect of their mechanical carb with a wrench.

robertg

iTrader: (2)

i found this link over in a post @ iroczone by Nick Silver (custom x here @ tgo)

http://www.show-n-go.net/gfiles/computer.html

yes, i know it's g-body, but some of it can be applied to f-bodies as well.

might give an idea as to how the ecm works. :shrug: