need to richen up my 3.2's fuel mixture. Discon. O2 sensor??

[don911]

I had my 87 on a dyno a couple of weeks ago. The dyno test showed that my fuel/air mixture is too lean. At around 2500 rpm, the mixture is 16%ish and goes down slowly as the rpm's increase. I'm around 14% at 6K rpms. I was told that around 12% is the target mixture. Will disconnecting the O2 sensor richen my mixture up? I was told that on a 3.2, about the only way to adjust the mixture is to install a fuel pressure regulator. Any suggestions?
Thanks,

[ChrisBennet]

Disconnecting the O2 sensor will rich things up - but only under part throttle conditions. You can richen the mixture across the range using the "fuel quality switch" on the back of your car's DME. Do a search.
-Chris
fuel quality switch

[Steve W]

If you increase your fuel pressure, as with a adjustable fuel pressure regulator, you will end up increasing the air fuel mixture everywhere, not the best idea. Bad for fuel economy, O2 sensor life, valve guide wear, and dilution of your motor oil with gasoline. If your car is running too lean, check that everything is fine mechanically with your car. If all is fine, the correct way of altering your fuel mixture is to install a aftermarket performance chip. Most chips increase the air fuel mixture at higher rpm levels for increased power. Believe me, the stock injectors and fuel pressure regulator can deliver more than enough fuel for even a lightly modified 3.2 with headers and exhaust.

Now if you need a chip, (shameless plug) I just happen to have a brand new 24 pin Autothority chip for an '87 with all its original packaging and instructions if you are interested.

[twin plugged targa]

Wooooe there!
Hold on a sec.
YOU CAN adjust your fuel mixture and make the car run lean or rich!.
DO NOT unplug your O2 sensor to do this!.
You may be able to do a search on this otherwise the other guys will direct you more acurately, but I did it will my car about a year ago and had it running fine!.
Evidently the factory set the car running slightly rich, but it can be adjusted.
Trick is ... where is the screw?
Unfortunately I sold my car a year ago!!!

But I beleive the screw is under the air mixture box? the box that is aluminum and webbed (sounds crazy I know but am trying to picture the engine bay!)
Help me out someone!!!!!
Anyway, I think you screw the screw in all the way and then factory setting is 5 rotations out and optimum is 8-10 out.
But do not quote me on that!
These guys will confirm screw turns
Common Guys!
Regards
Ben

[mskar]

The screw is on the airflow meter and is, afaik, for idle mixture adjustment only. By removing the large plastic cover on the meter, you can access a dial which sets the tension on the door, which will adjust your mixture throughout the range, not just at idle. My car (an 84 Euro graymarket conversion) had a previously removed plastic cover, which I reremoved to see what they had done. I turned the dial back to its original position (there was a worn spot) and my car has never run better, exhaust smells a bit richer but the difference is night and day especially at lower rpms. SteveW enlightened me to the purpose of the dial in a previous thread, I don't remember which way richens and which way tightens, but you can look up the thread for more info. Also, I completely agree with not making any adjustments to the airflow meter, disconnecting the o2 sensor etc unless you are sure you have everything else is working properly (plugs/wires/cap/rotor/no vacuum leaks, etc) If you're afm has not been previously opened, and everything is otherwise in tune, go with the autothority chip. My 2 cents

[don911]

Thanks for the info everyone. I'll do a search and try to find out more about the door tension switch.
Steve W. Send me an e-mail with info about your chip. I don't have SSI's so it's probably not mapped for my setup but I'd be interested in more info.
Thanks,