At one point I was running no O2 sensor and had my 5th and 6th ports being opened by the hole in the exhaust manifold where the O2 sensor would be. My car "seemed" faster with that setup. I now have an O2 sensor installed and I have my air pump assisting the ports. Lookin for any ideas. I didnt know if the car would run rich or lean without the O2 sensor. I figure it will run much richer. Thanks.

 

You won't notice any difference from running without an O2 sensor. It's only used during light-load cruise, and helps improve mileage slightly. Expect about 5% improvement in mixed-use driving. It has no effect on performance whatsoever.

 

I think it may have been that my O2 sensor hole in the exhaust helps the ports open better than the air pump. But I have noticed that at around 7000 rpms that my car wouldnt hit redline as fast. But it seems to rev quicker. (shrugs)

 

5% increase???????? is that it?

-Ben

 

My ports must not have opened up with the air pump idea. My car is faster and revs quicker with the O2 sensor out and the plumbing to the ports from the hole in the exhuast manifold.

 

you answered your own question1..

 

the air pump must not be supplying proper air flow.. pull that hunk of **** air pump out and route air to the ports via another way

 

I think you already know this, but what you've noticed has nothing to do with the O2 sensor, and everything to do with the operation of your 6PI system.

Why would you expect much more? Like I said, it's only used during light-load cruise, so it has no effect on fuel consumption any other time. When it is being used, the only way it could make a large improvement is if the engine ran very rich without it, but it doesn't.

That 5% improvement is what I measured over many hundreds of kilometers both with and without an O2 sensor, in an average mix of driving conditions.

Actually the air pump is the best way to do it. Where else do you think you'll get air pressure from?

 

Just trying to understand the aux ports, as the split air pipe that is supposed to open mine has been removed by some jerk off before i bought the car. I am trying to reconnect it so they open.

Am I supposed to put the split air pipe from my cat to the air pump? I've learned where it comes from the exuast, but im not sure where the other end goes, the fsm diagram is a bit shady as far as that end goes.

BTW, my car is an '87 n/a